INSTITUTE FOR TELECOMMUNICATION SCIENCES OF THE NATIONAL TELECOMMUNICATIONS AND INFORMATION ADMINISTRATION
ANNUAL TECHNICAL PROGRESS REPORT 1978 For the period from October 1, 1_977 through Sept. 30, 1978 U.S. DEPARTMENT OF COMMERCE
National Telecommunications and Information Administration
ADMINISTRATOR
Henry Geller
DEPUTY ADMINISTRATOR
Paul Bortz
OFFICE OF PLANNING & POLICY COORDINATION
Forrest Chisman, Director
L. Daniel O'Neill, Deputy Director
I I I I OFFICE OF THE CHIEF COUNSEL OFFICE OF OFFICE OF ADMINISTRATION OFFICE OF CONGRESSIONAL INTERNATIONAL AFFAIRS & PUBLIC AFFAIRS
Gregg Skall, Chief Counsel Cloyd Dodson, Director Veronica Ahern, Director Sharon Coffey, Director I
OFFICEI OF I I I OFFICE OF FEDERAL SYSTEMS INSTITUTE FOR OFFICE OF POLICY I TELECOMMUNICATIONS & SPECTRUM MANAGEMENT TELECOMMUNICATION SCIENCES ANALYSIS & DEVELOPMENT , APPLICATIONS Leland Johnson, Don Jansky, Associate Admin. Douglass Crombie, Associate Admin. Associate Administrator William Lucas William Fishman, William Utlaut, Dep. Associate Admin. I Associate Administrator Stan Cohn, Dep. Assoc. Admin. Dep. Assoc. Administrator I ITS ANNUAL TECHNICAL PROGRESS REPORT 1978
For the period October 1, 1977 through Sept. 30, 1978
U.S. DEPARTMENT OF COMMERCE Juanita M. Kreps, Secretary Henry Geller, Assistant Secretary for Communications and Information
FOREWORD g. In coordination with the Office of Fiscal year 19 78 saw the beginning of the Federal Systems and Spectrum Management, National Telecommunications and Informa provide advice and assistance to the tion Administration (NTIA), and a new era Administrator and the Director of Inter for the Institute for Telecommunication national Affairs in carrying out spectrum Sciences. NTIA was formed, by Presiden management related aspects of NTIA's tial Order No. 1, 19 77, by combining the international policy responsibilities and former Office of Telecommunications Policy perform such other duties related to those (from the Executive Office of the Presi responsibilities as the Administrator dent) and the Office of Telecommunications shall designate. (from the Department of Commerce). NTIA is now located in the Department of Com As a result, ITS will continue to be heav merce under the new Assistant Secretary ily involved in research and engineering for Communications and Information. for increasing the availability of the spectrum by scientific and engineering ITS is one of the Offices of the new techniques, and in overcoming natural, organization and is responsible, on behalf engineering and cost factors limiting the of the Administrator of NTIA, for the performance of telecommunication systems. telecommunications technology research pr ograms of NTIA and for providing tech We expect that more of our efforts will be nical research support to other elements in collaboration with, and support for, of NTIA as well as other agencies on a our sister offices in NTIA. These offices reimbursable basis. To perform these fun are those of Policy Analysis and Develop ctions it shall, as stated in Departmental ment, Telecommunications Application, Fed Orders: eral Systems and Spectrum Management, and International Affairs. In addition, NTIA a. Conduct and coordinate technical anal recognizes the national value of our sup yses of telecommunications and information port for other Federal Agencies and policy options. encourages such activities, particularly wh ere these can occur at the planning b. Acquire, analyze, synthesize and dis level. seminate data and perform research in gen eral on the description and prediction of The public will expect more from telecom electromagnetic wave propagation and the munications in the future. More quality, conditions which affect propagation, on more diversity of services, and more value the nature of electromagnetic noise and for the costs. It is NTIA's role, on the interference, and on methods for improving Government side, to help their expecta the use of the spectrum for telecommunica tions be fulfilled. Without research and tions purposes; prepare and issue predic its applications in economics, in legal tions of electromagnetic wave propagation issues and in telecommunications engineer conditions and warnings of disturbances in ing, these expectations will not be met. those conditions; develop methods of meas ITS welcomes the opportunity to partici urement of system performance and stand pate and to assist in the development of ards of practice for telecommunications. soundly based public telecommunications policies, and in sound telecommunication c. Conduct research and analysis of elec applications by the Federal Government. tromagnetic propagation; radio systems characteristics, and operating techniques affecting the utilization of electromag netic spectrum, in coordination with spec ialized, related research and analysis performed by other Federal agencies in their areas of responsibility.
d. Conduct research and analysis in the general field of telecommunication sci ences in support of assigned functions and in support of other Government agencies and State and local governments.
e. Provide scientific, engineering, and technical expertise, as the central Federal Government laboratories for research on transmission of radio waves. f. Coordinate or undertake, on behalf of and at the direction of the Administrator, policy programs with major scientific or technical content.
iii
TABLE OF' CONTENTS
FOREWORD iii
LIST OF FIGURES vii
LIST OF TABLES ix
INTRODUCTION 1
CHAPTER 1. EFFICIENT USE OF THE SPECTRUM 5
SECTION 1.1. SPECTRUM ENGINEERING TECHNIQUES 5
SECTION 1.2. SPECTRUM ENGINEERING FOR EFFECTIVE SPECTRUM USE 12
SECTION 1. 3. ADVANCED INSTRUMENTATION AND SPEC'l'RUM MEASUREMENTS 17
CHAPTER 2. SYSTEMS ENGINEERING AND EVALUATION 33
SECTION 2.1. COMMUNICATION SERVICES ENGINEERING 33
SECTION 2.2. SATELLITE COMMUN ICATIONS 45
SECTION 2.3. TERRESTRIAL RADIO SYSTEM PERFORMANCE 47
SECTION 2.4. SIMULATION AND STANDARDS 55
SECTION 2. 5. FIBER OPTIC CO.MMUNICA'UONS 58
CHAPTER 3. EM WAVE TRANSMISSION 65
SECTION 3. 1. WAVE TRANSMISSION CHARACTERIS'riCS 65
SECTION 3.2. CHARACTERISTICS OF 'ri:IE 'l'RANSMISSION MEDIA 65
3.2.1. Atmospheric Characteristics 67
3.2.2. Ionospheric Characteristics and Effects 75
SECTION 3.3. DEVELOPMENT AND IMPLEMENTATION OF EM WAVE TRANSMISSION MODELS 77
3.3.1. Atmospheric Transmission Models 77
3.3.2. Ionospheric Transmission Models 91
3.3.3. Terrain Models 91
SECTION 3. 4. PREDICTION OF TRANSMISSION PARAME'I'ERS AND SYSTEM PERFORMANCE 94
3.4.1. Long-Term Ionospheric Predictions 94
SECTION 3.5. APPLICATIONS 97
3.5.1. Antennas and Radiation 97
3.5.2. Transmission Through the Atmosphere: Applications 99
3.5.3. CCIR Participation llO
ANNEX I. ITS PROJECTS FOR F'Y 7 8 ll5
ANNEX II. ORGANIZATIONAL DIRECTORY ll7
ANNEX III. ALPHABETICAL LISTING OF ITS EMPLOYEES 119
ANNEX IV. ITS PUBLICATIONS FOR FISCAL YEAR 1978 121
ANNEX V. GENERAL AND HISTORICAL INFORMATION OF I'l'S 125
v
LIST OF FIGURES
FIGURE TI'I'LE PAGE
1-l Average operational range as constrained by interference for 7 varying levels of usage . l-2 Washington . The shaded areas indicate in succession where Grade 8 A service is available from 1, 2, 3, and 5 (or more) television stations . l- 3 Statistics of television coverage near Washington. 10 l-4 Measurements of minimum signal-to-noise ratio required for 13 acceptable performance of TV interfered with by FM interference (dashed lines) and FCC-recommended pro tection ratio (solid line ) . l-5 Estimates and measurements of interference potential of a spread 14 spectrum signal compared to a narrowband FM LMR interferer. l-6 The Radio Sp ectrum Me asurement System (RSMS) undergo ing antenna 18 calibration at the ITS antenna range . l-7 Major elements of the Radio Spectrum Measurement System . 19 l-8 Special de s ign precautions to insure high quality me asurements . 22 l-9 RSMS antenna array. 23 l-10 SAC Strategic Training Range for Electron ic Warfare , La Junta, 25 Colorado . l-11 The TAC/Signal Analysis System (SAS) for electronic warfare (EW) 27 test and exercise evaluation . l-12 Aircraft used for measuring CATV radiated signals . 30 l-13 ITS developed instrumentation , as installed in flight ·test 31 aircraft for acquiring data measured as part of the CATV interference evaluation project.
2-1 Data co��unications project overview . 34
2-2 Summary of selected performance parameters. 36
2-3 Access time histogram. 37
2-4 EMSS station s as part of EMSS sys tem as an example of planning 40 factors .
2-5 Interoffice signaling concepts . 43
2-6 Main interfaces in the access area . 44
2-7 Profile plot and ray trace . 48
2-8 Digital European Backbone System , Phase I. 49
2-9 Received signal level distribution for 160 km link. 50
2-10 Sample enhanced fault alarm system displays. 51
2-11 Sample fade caused by aircraft. 53
2-12 Aircraft obstruction . 54
2-13 Theoretical improvement in digital spread-spectrum receiver 57 performance provided by adaptive filter with CW interference .
2-14 Emergency medical services communications . 59
vii FIGURE 'l'ITLE PAGE
3-1 Observed and predicted bit-error probability versus round trip delay 66 fo r 1..5 GHz indoor multipath experiment.
- + 3-2 Examp les of o2·-MS Zeeman patterns for 1 and 25 lines at h = 55 km 68 (p = 42.5 Pa and T = 260.8 K; U.S. Std. Atm. 76) for two magnetic 5 field strengths, H z 3 (left half) , H = 6 (right half) x lo- T, and the unsplit line, H = 0. Zeeman patterns rr and o = a+ + o- for the 7- line at an altitude, h = 100 km.
3-3 Height profiles of constant attenuation rates (0 - 10 dB/km) for 69 clear air.
3-4 Clear air zenith attenuai:ion for 3 humidi·ty models (5, 50, 100% RH 70 at h = 0).
3-5 Orbiting standards platform illustration. 72
3-6 Ten foot receiving di sh with receiver front end at prime focus . 73
3-7 Received signal on terrestrial and earth satellite link versus 74 t�ne during a rain event. Satellite beacon signal received from COMS'.l'AR Dl beacon at 128° '\ve st longitude.
3-·8 Single engine aircraft equipped to make simultaneous measurements 76 of refractivity, temperature, and pressure.
3-9 Samp le of long delayed signal (137.5 ms ) . 78
3·.. 10 Sample information page from catalog. 80
3·-11 Canyonlands transmitter site looking along the measurement radial . 82
3-1.2 The Canyon lands site as viewed from Dead Horse Po int . The radial 83 crosses the three plateaus on the left.
3-1.3 Path profile plot for Canyonlands, Utah. '34
3-14 Me asured received signal and noise levels, Canyonlands path, 2.0 MHz . 85
3-15 Pre liminary plot of propagation loss measurements made at 86 Canyonlands, Ut:ah, site (X) and ·the predic·tions of loss from WAGNER (solid line) for 2 l'1Hz.
3-16 Path locations for the long path 15 GHz mu ltipath fading tests . 87
3-17 Transmission loss curve s, air traffic control. Sample "applications " 88 plot.
3-18 Service volume, 'rJ\CAN. Sample "applica·tions" plot . 89
3-19 A sample comparison of predictions and measured data, this one 90 being an actual facility overflight.
3-2 0 Service areas for comrnand/destruc·t t.ransm:i.t·t. ing an·tenna w.ith 92 high beam elevation angle.
3-·2 1 Pa th loss in dBU/Kw ve rsus di stance in km for a path with 95 transmit:ter in Yuma, AZ, over the Tinajas Altas mountains toward Luke AF'B.
'.l'OPOG tape areas for CONUS. 96
3··23 Interior view of ons.i·te antenna measurement van capable of 98 providing power gain versus aximuth and elevation angle over a frequency range from MF' to X-band.
3-24 Buried MF antenna power ga in relative to that of a short, 98 vertical dipole versus azirnuth--1 3 deg elevation angle.
viii FIGURE TITLE PAGE
3-25 Overall frequency usage histogram. 100
3-26 Overall take-off angle distributions. 101
3-27 Management model organization . 103
3-28 Proposed Mo j ave rectenna site. 107
3-29 An examp le of mu ltipath observed in the impulse response measured 111 over a long over-water LOS microwave path . The sequence progresses from top to bottom in time , at 100 ms intervals . The delay time scale is 10 ns/cm . The response shows a two-path propagation mode with a delay of approximately 8 to 10 ns .
3-30 A portion of the U.S. delegation to the CCIR XIV Plenary Assembly , 113 wh ich included four of the NTIA/ITS staff .
LIST OF TABLES TABLE 1-1 Number of Simultaneous Users per MHz Bandwidth when Mobile-to 7 Mobile Links are Getting Specified Operational Range
1-2 , 3, 4 11
1-5 Probability that S/I > R Given that at Least One Transmitter is on. 16 Mdbile-to-Base Transmission in Urban Areas
2-la & b 3 EMSS Candidates 39
2-2 Flowchart for System Analysis 62
2":'3 Optical Communications De s ign Flow Chart 63
3-1 Program Wagl in Comparisons 93
3-2 Categories of Habitable Structures 105
3-3 Selected Site Distances from Hoj ave Rectenna 105
3-4 Induced Functional Degradation Summary - Hoj ave Area 108
ix INTRODUCTION than that of single links; and developing usable criteria for evaluating system per Three divisions in ITS perform the techni formance versus spectrum requirements. cal work reported here. They , and their di rectors , are: Most of the directly- funded portion of Spectrum Utilization this program element is concerned with the (John P. Murray) basic issues mentioned above. A maj or Systems Technology and Standards part of the effort is in support of the ( Joseph A. Hul l) NTIA Office of Federal Systems and Spec Applied El ectromagnetic Science trum Management, wh ich manag es the Govern (Donald L. Lucas) me nt portion of the spectrum. In addi tion, work for other Federal agencies is This Division struc ture correlates closely concerned with electromagnetic compatibil wi th the primary program areas of ITS. ity analysis and radio coverage estima These program areas are : tion. Efficient Use of the Spectrum Systems Eng ineering and Evaluation Highlights of FY-78 activities include: El ectromagnetic Wave Transmission Evaluation of the spectrum efficiency These three prog ram elements are not inde of FM , AM , and SSB modul ation for pendent of each other, but have a high Personal Radio services, and of degree of interaction. For exampl e, Spread Spectrum modul ation for mobile transmission phenomena pl ay an important radios. role in determining whether radio systems wil l work in the field, as do que stions of Produc tion of TV coverage maps for mutual interference between systems or the FCC. subsystems. Variability of transmission loss through the atmosphere determines the Studie s of the sharing of the spec physical separa tion between systems shar trum by AM broadcast and radio ing the same frequency and thus affects navig ation systems. the efficiency of spectrum use. Eng ineer ing of systems to obtain the required per Development of spectrum monitoring formance demands adequa te knowledge of equipment for use in evaluating the transmission loss and distortion, as we ll effectiveness of airborne electronic as the effects of interference. counter-me asures systems.
Efficient Use of the Spectrum De tail s of the program are given in Chapter 1. The obje ctive of this program element is : Engineering and Eva luation of Sys tems To show how to substantial ly increase the permissible number of users in The objective of this program element is: congested regions of the spectrum. To provide user-oriented telecommuni The spectrum is a limited natural resource cation system performance criteria being subjected to ever-increasing and methods of performance me asure de mands. Our role is to examine and ment , and to relate these to more understand the basic scientific and engin conventional engineering parameters. eering factors wh ich affect the efficiency of spectrum util ization , and to foster and ITS has recognized that there is a signif encourage the use of technique s wh ich max icant need for adequa te means of specify imize the number of spectrum users re ceiv ing , evaluating , and me asuring the per ing satis factory performance in a given formance of telecommunic ation systems , geographical area , under interference from a user's point of view , and is at limited conditions. tempting to fil l this void. Criteria which are system independent , and which Major op portunities for improving the repre sent performance at the user 's inter efficiency with which the spectrum is used face with the system , are badly needed for inc lude the proper applic ation of band comparing alternative or competing serv width expansion; reduc tion of radiation in ices and for evaluating their benefits unwanted dire ctions from directive anten versus cos t. In addition , improved tech nas; improving the predic tability of the nique s for the measurement of performance signal strength of both wanted and unwant of multipl exed signals in the engineering ed signals; unders tanding the interactions sense , and in real time on message trunks , betwe en systems which are clos ely-spaced are badly needed to de tect incipient fail geographical ly; recognizing that interfer ure s. ITS is deve loping criteria and ence from co-channel signal s may consti me asurement me thods for both voice and tute a stronger and di fferent performance da ta transmission. limitation than natural or man-made noise; recognizing the de sirability of maximizing In addition, this prog ram element is con the joint performance of many links ra ther cerned with channe l simul ation and signal s. Scattering and mul tipath may evaluation of modem technique s, communica limit the avail able bandwidth . tions via fiber optics , and improved use of satellites for communications . ITS efforts in FY 78 continued to be directed mainly at the higher frequency Ch annel simul a tion is concerned with mak end of the spectrum . Notable achievements ing availab le , in the laboratory , simu include : lated channel s wh ich re flect accurately , in a statistical sense , the various mul ti De sign and test of buried MF and UHF plicative effects or di stortions which antenna prototype s for potential use occur on real channels , and wh ich may in the MX bal listic mis sil e system . cause a greater limitation to performance than additive noise. Such labora tory Initial evaluation of potential im channel mode ls are used to test and com pacts of the Solar Power Satellite pare real hardware under control led condi high power microwave beam on the tions much more economically than can be atmosphere and on terrestrial com done in the field. munications .
Com munications by fiber optics promises to Da ta col lection on mul tipath fading have significant impact on the transmis on long microwave paths . sion of very wideband signals, and may eventually repl ace terrestrial and submar Expl oration of the feasibility of ine coaxial cables and mm wave-guide s for recovering radio signal s in iono high data-rate transmission. spheric ducts by use of the Plattevil le high power transmitter. The satel lite activity is concerned with overcoming the regul a tory , economic , and De tail s of this program are found in technical barriers to the use of small Chapter 3. earth terminal satel lite systems .
Significant achievements in FY-78 include : ITS continued to provide support to the Continuation of support to u.s. u.s. and International ITU committees of Pos tal service in development of CCITT and CCIR. Preparation for WARC-79 el ectronic message service systems . wa s a significant part of the CCIR effort . This activity included participation in Development of a de sk-top calculator the IRAC AdHoc 144 Committee and prepara program for de sign of line-of-sight tion for the CCIR Special Preparatory microwave links . Meeting to be held late in 19 78. ITS leaders in these activities include W. F. Production of an Emergency Medical Utl aut , J. P. Murray , P. M. McManamon, c. Service Planning guide for use by M. Rush , H. T. Dough erty , and D. L. Lucas. nontechnical personnel in the pro curement of emergency telecommunica Sueeort for Other Agencies tion services. Much of the work described in this report Evaluation of the characteristics of is in support of , and reimbursed by , other single-mode optical fibers for long Federal Ag encie s. This both helps solve di stance high capacity communica technical problems of these Agencie s and tions . aids ITS in maintaining broad awareness of national te lecommunication problems. It De tail s of this program are found in al so helps to provide data for use in the Chapter 2. development of mode ls which become avail able to those requiring them and thus Electromagnetic wave Transmission helps ITS to fulfil l it s responsibilities to the public. An important part of this The objective of this program element is : effort , in each of the program areas , is assessing technical requirements; assist To provide complete , quantitative EM ing in de finition of specifications for wave transmission characteristics of telecommunica tion equipment and systems; communication channe ls for the many and evaluating their performance . This spectral regions of current interest. work helps the Ag encies in their procure ments from industry , and by limiting the ITS effort s in this area are aimed at im rang e of alternative s makes it easier for proving the probability of successful de industry to re spond to the Agencie s' ployment of radio systems de signed to op needs . erate near the state-of-the-art , insofar as propagation is concerned . De leterious As in previous years , our work in FY- 78 propagation effects form a basic limita for other Federal Agencies wa s oriented tion to the performance of radio systems . closely towards NTIA's goals. NTIA' s cri Attenuation, scattering , ducting , and teria for acceptance of work from Other refraction affect both wanted and unwanted Agencie s can be summarized as follows :
2 1. It falls within the authority of the Secretary of Commerce to undertake the work.
2. The work is relevant to na tional goals and commitments and has impact on these goals and com mitments.
3. The work cannot be readily per formed by the priva te sector (with certain exceptions such as un avoid able conflict of inter est , intolerable delays, exces sively higher costs, or unique facilities or capabilities within ITS) •
4. The work contributes to NTIA' s goals.
5. The work does not conflict with other ongoing work within NTIA.
All these criteria mus t be met.
The revised criteria will continue to ensure that the work we do for Federal Agencies will be a proper function of Government and consis tent with the mis sion of NTIA and the Department of Commerce.
Ac knowledsement
R. B. Stoner was responsible for the prep aration of the report , from ma terial pro vided by the Associate Directors - J.P. Murray , J.A. Hull , and D. L. Lucas. He wa s ably assisted by other ITS staff.
3
techniques , but even so they were arcane CHAPTER 1. EFFICIENT USE OF enough so that relatively few people used THE SPECTRUM them, and even fewer unders tood them.
Our goals in this part of the program are The radio , or electromagne tic , spectrum to develop a family of such technique s has seen dramatic growth in demand and that is based on a sound knowledge of the use since the beginning of World War II. physical characteris tics of the problem, Since that time , a great range of new the technical properties of equipment spectrum-dependent services has evolved . involved , the practical way in which that American indus try , government , and pri equipment is used , and the influence that vate citizens have put the spectrum to Mo ther Nature brings to bear. If we are work in such profusion that now satura success ful in developing such techniques , tion appears imminent and , in some cas es , they are ne cessarily complex and conse has already occurred . To prov�de for new quently difficult to use and understand . and expanded us e, two major aliernatives We are aggressively working to overcome exis t. One is to exploit new regions of these barriers to effective use by care the spectrum at progressively higher ful do cumentation and by developing frequencies. The second is to provide computer methods that are easily used and for a better understanding of the basic provide results in the user's context . physical principles upon which spectrum use depends and , complementing this Cons ervatism in many cas es equates to unders tanding , provide for more effective was ted spectrum. We address this problem means of managing spectrum use . by building techniques which incorporate a comprehensive statistical analy sis of Spectrum use by the u.s. government alone the many variables (and their complex is growing nine percent annually in those inter-actions ) which affect the results . frequency regions where equipment is By so doing , we allow the user to be as readily available . Embryonic efforts are liberal or conservative as he chooses . being made to use the even higher fre quencies above 10 GHz where equipment For over a decade , government , academic , still remains to be developed for many and industrial groups have avo cated deve applications . lopment of methods for improving the overall effectiveness of the utilization The National Telecommunications and of the spectrum (as opposed to the opti Information Administration, Ins titute for mization of the performance of individual Telecommunication Sciences (NTIA/ITS ) systems) . This concern paralleled and conducts a program of research and deve even predated similar realizations that lopment which addresses both of these ideal common use of environmental alternatives. Much of the work being resources such as air and water may not done to extend the use of the spectrum to coincide with economic maximization of an nigher frequencies is discussed in the individual user's profits . Electromagne tic Wave Transmission chapter of this report . That chapter also The developments reported here are dis provides brief mention of some of the cussed with current applications in mind . work being done to improve our under But their true value lies in their standing of propagation problems in these general character. In mo st cases , these regions of the radio spectrum that are methods can be readily adapted to meet already extensively used . many new requirements involving a broad range of telecommunications needs and In this chapter, some highlights of the services . Th e presentation of summary NTIA/ITS program directly concerned with results in graphic form (particularly as spectrum engineering are reviewed . Many maps and map overlays), the development of these spectrum engineering pro� ects of demographic results , and the design of draw heavily on experience from other interactive computer programs that make programs in ITS , including antenna design it easy to ask "what if? " questions are and measurement , channel characterization symptomatic of our continuing effort to and system performance , and the many bridge the gap between technology and the propagation related efforts. planners and policy makers .
Quantitative analy sis of the tradeoffs SECTION 1. 1 SPECTRUM ENGINEERING between equipment specifications , opera TECHNIQUES ting procedures, and Government regulations can show how to get maximum communications yield from the radio Traditionally , such techniques have been spectrum resource . This year, in the developed to evaluate a specific situa Tradeoffs for Spectrum Us e Project , tion, usually with a series of "safe" or technical trad eoffs for spectrum effi "conservative " assumptions . Conservatism ciency in a personal radio service were allowed for some simplicity in these studied in cooperation with the Personal
5 Radio Planning Group ( PRPG ) of the is tic model described in the 1977 report . Federal Communications Co mmis sion . Figure 1-l shows the average operational , Citiz en 's band radio channels are already range , OR 5 as a function of the number badly conges ted in metropolitan areas , of simultaneous interferers for the con and the number of licensed sets is ditions shown on the figure . Th e increasing several million per year. As capacity , or saturation level, of a a result , the Federal Co mmunica tions personal radio band can be determined Commis sion has been studying the possi using such a figure . Fo r example , if the bility of establishing a new Personal regulatory authority decides that the Radio Service to supplement CB . service should provide a median opera tional range of three km for mobile-to Earlier studies by PRPG had selected the mobile commmunica tions , FM modulation 220-224 MHz and 900 MHz bands as candi with 25 kHz channel spacing wil support dates for a new personal radio service . five simultaneous users per channel (four De sign parameters that might affect interferers plus the wanted signal ) at spectrum efficiency and service quality saturation . Th e SSB-AM will support only are modulation type , channel width , and two users per channe l, but it is still radiated power . Th e different propaga more spectrally efficient than 25 kHz FM tion characteris tics and ambient noise in because 25 kHz will hold five SSB-AM the two frequency bands also affect the channels and hence ten users in the same results . space .
Modulation types and channel wid ths This idea is used with more extensive considered were as follows : Double data to cons truct Table l, which shows Sideband Amplitude Modulation (DSB-AM ) the total number of users per megahertz with a channel width of 10 kHz; Single of bandwidth that each kind of modula tion Sideband AM (SSB-AM ) with a channel width will allow for different specified opera of five kH z; and Frequency Modulation tional ranges . Calcula tions were made (FM) for channel widths of 15 , 25, 50 and for FM bandwidths greater than 25 kHz, 100 kHz . Transmitter power was variable , but these bandwid ths did not allow as but mo st calcula tions assumed five W. many users/megahertz so the values are The average mobile station was assumed to no t shown. have a quarter wave whip antenna mounted on the roof of a vehicle , between one and Table l-1 shows that SSB-AM is about two meters above the ground. An average twice as spectrum efficient as the other ba se station was assumed to have a 5/8 contenders . It is important to note tha t wavelength whip or a two-element Yagi this conclusion is a function of the antenna mounted five to ten meters above required output signal-to-noise ratio . ground . Th e variation in installation .If the required ratio were much higher- heights and antenna types was accounted say 30 dB or more- -it is possible that for by assuming that the effective frequency modulation with channel wid ths radiated power had a statistical dis tri greater than 25 kHz would be more bution around these average ca ses . efficient .
A statistical propagation mo del, which A project to draw TV Coverage Maps was depended on the terrain paramete1:·.6.h was sponsored by the Federal Communica tions used . Fairly smooth terrain or suburban Co mmis sion. Its finished product was a development was represented by.6.h = 90 m, set of co mputer programs which may be and rough terrain or urban development used to draw the maps and to compute wa s represented by .t,.h = 200 m. associated statis tics under various con ditions and suppositions . Th e programs Transceivers were assumed to be dis tri employ the FCC Television Data Base , a buted uniformly but randomly over a file of 1970 population density values , metropolitan area, and users were assumed and several "environment.p.l" files that to transmit at random times (no cour provide values for propagation parama te sy ). Th e density of users was varied ters . A sample map is shown in Figure l- to find the maximum number of users per 2. It displays a small portion of the channel for a desired quality of service . United States including Washington, Philadelphia , and New York City . Th e Quality of service was assumed to be shaded areas indicate where one can given by the signal- to-noise or signal expect to find at le ast Grade A service to-interference ratio at the output of from one , three and five (or more ) the demodula tor. Th e results here are television stations on any of the 82 for an output S/I ratio of 17 dB . Then channels . the operational range ( OR ) is defined to be the range at which thi� S/I ratio was A principal feature of the final program achieved on lOOx % of the attempted is that while computing areas and popu contacts . lations of the various categories of coverage , it simultaneously computes an Calculations were made with a probabil- es timate of the probable errors of these
6 223 MHz 6h = 90 m
2 4 6 8 10 12 Ni Figure 1-1. Average operational range as constrained by interference for varying levels of usage.
Table 1-1. Number of Simultaneous Users per MHz Bandwidth when Mobile-to-Mobile Links are Getting Specified Operational Range
(Assumes equal loading of channels; 17 dB output S/I; interference
limited case; 223 MHz; 6h = 90 m. Eighty percent of users are mobile; 20 percent are base stations,)
Channel Width, kHz SSB-AM DSB-AM FM Specified oR , km .5 5 10 15 25
2 540 270 320 288
3 420 210 233 192
4 340 170 187 152
5 300 150 160 128
6 260 130 140 112
7 ..
...
...... : : .... :
......
...
Fig�re 1-2 . Washington . The shaded areas indicate in succession where Grade A service is available from 1, 2, 3, and 5 (or more) television stations .
8 quantities . This , one should note , is been developed at ITS to me asure voice not a trivial task . If for example , no intelligibility . A dis tortion me asure is one lives in a particular area then it obtained using Linear Prediction Coding does not matter how bad the es timates of (LPC), a mathematical te chnique widely received field strengths are , the known for its app lication to the ana lysis probable error of population there will and synthesis of speech . Th e feasibil ity be zero. Clearly , the probable errors of using LPC to develop an ob jective must somehow be re lated to the magnitude intelligibility measure has been of population densities. Sources of demons trated. error include not only our ignorance of radio propagation losses , but also the The obj ective of this measurement task is inexactitude of some of the sta tion to eva luate the potential of using the parameters and suspected errors in our LPC method to obtain Ar ticulation Scores environment al files . (AS) scores for different interference situations . In Figure 1-3 is the output of statistics corresponding to the map in Figure 1-2. Re ceiver performance measurements have Below each computed value is a second been made on both a narrow-band AM and FM value (fol lowed by the letter "X" ) which receiver with int erference being noise, a is the corre sponding probable error . simil ar type signal {AM or FM ), or pulsed Note that there are over two million co-channel signal . Th e AS , AI and LPC people in that region who do not receive scores will be measured and compared. Grade A service from even one television The output of the project will be pre station. sented in a letter report .
This technique has broad future app lica A study (AM Broadcast and Ra dio- location tions in all broadcast situations , with Sharing ) was undertaken at the request of FM as the mos t obvious example . Es tima the Federal Communication Commission tes of such coverage from satellites (FCC ) to provide technical da ta for alone or in combination with conventional determining the feasibility of extending broadcast facilities would be possible . the AM broadcast band from 1615 kHz to 1800 kHz , on an equal- status sharing Spectrum planning techniques rely on some basis with ra dio-location services. Th e measure of desired system performance as study was limited to cons ideration of one a key factor in determining spectrum specific narrow-band ra dio- location sharing potential . Such a performance system, the Decca Hi-Fix System, chosen measure has been very difficult to find because of its widespread use in many for voice communica tion . areas . Th e basic methodology of the study wa s to ca lculate the ratio R of the An objective evaluation of receiver geographic distances from interfering performance in terms of voice intelligi transmitter to intended-receiver and bility has long been a difficult problem. de sired transmitter to intended-receiver. In the past , both subjective and For interference from a radio- location obj ective me asurement techniques have transmit ter to a broadcast receiver , been used to assess the intelligibility calculations were performed for signal of voice communica tion systems . Th e sub to-interference ratios of 25 dB and 40 jective method involves trained speakers dB , and for two types of receivers having and listeners that dire ct ly score the diff erent pre-detection bandwidths . Th e percentage of words th at are correctly results of these calculations are shown perceived. Unfortuna te ly, subjective in Ta ble 1-2 and Table 1-3. For inter scoring methods are time consuming , ference from a broadcast transmitter to a difficult and expensive , and as a re sul t, radio-location receiver, the ca lculations are not used extensively . were based on a 1 dB reduction in effective S/N ratio at the radio- location One objective method used in the past to receiver. For this case, the study also measure voice intelligibility has been took into account the out-of-band the Articulation Index {AI ) de fined as an emis sions of the broadcast transmitters average of the signa l- to-noise ratio in (i.e. , due to harmonic and inter several audio frequency bands . Several modulation dis tortion products ). Th e automated technique s to obtain AI have re sults of these calculations are been used. The two most well-known presented in Ta ble 1-4. automatic technique s are the Speech Communication Index Meter (SCIM) and the Voice Intelligibility Analysis Set (VIAS ). Al though the AI technique is more practical than the subjective AS technique , AI is not one-to-one correlated with the subjective measure ment technique .
Recently a new ob j ective technique has
9 WASHINGTON
USING- FCC BASE 77/09/20.
LICENSED, PRIMARY STATIONS ONLY
SERVICE THRESHOLD- GRADE A (INTERFERENCE IS IGNORED) 68. 71. 74. DBU
FOR POPULATION DENSITIES 10/SQ MI 50/SQ MI 100/SQ MI 250/SQ MI NO. OF . . . . TOTALS SERVICES
. . . . 1 OR MORE 2780 POP. 378100 POP. 750700 POP. 2185000 POP. 28912000 POP. 32228000 POP. 460X 9000X 14700X 29000X 34000X 48000X 353 SQ MI 10890 SQ MI 10290 SQ MI 13070 SQ MI 18900 SQ MI 53510 SQ MI 147X 320X 240X 220X 200X 52 0X . . . . 2 OR MORE 1000 POP. 159700 POP. 371000 POP. 1488000 POP. 28455000 POP. 30475000 POP. 200X 5800X 12700X 31000X 50000X 60000X f-' 0 133 SQ MI 4560 SQ MI 5050 SQ MI 8780 SQ MI 17820 SQ MI 36340 SQ MI 108X 190X 190X 200X 190X 400X
. . . 3 OR MORE 657 POP. 69700 POP. 151800-POP. 917000 POP. 27785000 POP. 28924000 POP. 129X 4100X 8200X 24000X 64000X 69000X 90 SQ MI 1948 SQ MI 2041 SQ MI 5260 SQ MI 16340 SQ MI 25680 SQ MI 94X 139X 127X 150X 190X 320X . . . . 5 OR MORE 410 POP. 12700 POP. 36400 POP. 413000 POP. 26008000 POP. 26471000 POP. 108X 2300X 5400X 19000X 77000X 79000X 53 SQ MI 314 SQ MI 454 SQ MI 2326 SQ MI 12600 SQ MI 15740 SQ MI 69X 79X 90X 123X 190X 270X . . . . NONE 12870 POP. 493500 POP. 497500 POP. 854000 POP. 590000 POP. 2448000 POP. 460X 9000X 14700X 29000X 34000X 48000X 2080 SQ MI 15860 SQ MI 7020 SQ MI 5520 SQ MI 1490 SQ MI 31980 SQ MI 410X 490X 300X 290X 280X 820X
Figure 1-3 . Statistics of television coverage near Washington . TABLE 1-2
Carrier Output S/I = 25 dB Output S/I 40 dB Separation Input S/I R Input S/I R 1.5 kHz 25 dB 1.1 40 dB 6 -> ' 3 18. 5 . 5 33.5 3 5 8.5 .15 23.5 1 8 0 .06 15 .36 10 -4 .04 11 .22 12 -7 .03 8 .14
Receiver IF bandwidth : -3 dB 4.5 kHz -20 dB 14 kHz -40 dB 40 kHz
dist. radioloc . xmtr to broadcast rcvr R dist. broadcast xmtr to radioloc . rcvr
Broadcast transmitter power = 10 kW (carrier ) Radiolocation transmitter power = 10 W (low mode )
Table 1-3
Carrier Output S/I = 25 dB Output S/I 40 dB Separation Input S/I R Input S/I R
->3 kHz 25 dB 1.1 40 dB 6 5 19.5 . 6 34.5 3.3 8 11 .22 26 1.2 10 6.5 .13 21.5 .75 12 4 .1 19 .56
Receiver IF bandwidth : -3 dB 8 kHz -20 dB 22 kHz -40 dB 65 kHz
dist. radioloc . xmtr to broadcast rcvr R dist. broadcast xmtr to radioloc . rcvr
Broadcast transmitter power = 10 kW (carrier) Radiolocation transmitter power = 10 W (low mode)
TABLE 1-4
Ca,rrier Separation
>75 kHz <0.1 30-75 kHz 0..7 15-30 kHz 2.4 0.5-15 kHz 60 5-15 kHz 2*
*W ith 40 dB notch filter in the broadcast transmitter audio circuits at a frequency equal to the carrier separation .
_ dist. broadcast xmtr to radioloc rcvr R - dist . radioloc . xmtr to radioloc . rcvr
Broadcast transmitter power = 10 kW (carrier) Radiolocation transmitter power = 10 W (low mode)
11 A limited set of laboratory measurements SECTION 1. 2 SPECTRUM ENG INEERING FOR was made to check this conclusion. In EFFECTIVE SPECTRUM USE the tests , FM interference from a conven tional LMR FM generator was set at a recorded level and added to a TV signal In addition to the development of new received on a labora tory antenna and analytical and measurement techniques , viewed on a 19-inch portable color TV. ITS applies the results of such work to The tes t subject was then asked to ad just specific problems of concern to various the attenuator of a spread spectrum agencies . One import ant factor in signal to get a "comparable" level of planning for new developments is our interference . The sub ject could switch experience with such projects where the between the FM and SS interference as practical needs of opera tional agencies often as he desired to compare the must be recognized. interference .
Two projects sponsored by the Federal Figure l-5 shows our theoretical es timate Communications Commis sion examined the of the potential for int erference of SS potential of spread- spectrum (SS ) modula to TV as a solid line. The shaded area , tion for the land-mobile radio (LMR ) for bandwid ths greater than 2 MHz , shows service . The objective of the Spread the uncertainty or variability due to Spectrum LMR-TV Sharing proj ect was to different filtering characteris tics of TV compare the conditions under which receivers . Th e points on Figure l-5 show spread- spectrum land-mobile radio and the median value for nine observations by televis ion stations can share spectrum three observers , and the bars through the with the conditions under which conven points are the ranges of measurements tional narrow-band FM land-mobile radio with the highest and lowest points and television statios can share removed . spectrum . This can be done by comparing the protection ratios req uired against Considering the small sample and the the two types of interference . range of values shown in Figure 1-4, the measurements confirm the theoretical The dashed lines in Figure l- 4 show the es timates . This is a very useful result , measured minimum signal-to-interference because much is known about the ratios neces sary to achieve acceptable interference of conventional FM LMR to performance with interference from con TV. This available knowledge can be ventional FM land-mobile transmis sions applied to analysis of interference of with various modulations . (Details are spread- spectrum LMR signals of the same contained in the NTIA Report 78-6, "A total power , as long as the SS bandwidth Preliminary Es timate of the Effects of is les s than 2 MHz . If the bandwidth is Spread Spectrum Interference on TV, " by greater than 2 MHz , Figure 1-5 can be John R. Juroshek. ) Also shown on used to es timate the power that is to be Figure l- 4 is the FCC recommended protec compared with FM interference . tion ratio for interference to color TV. It would appear from the figure that the Th e ob j ective of the second Spread interference mechanism of interest is a Spectrum La nd-Mobile Radio Systems simple interaction between an amplitude project was to define and es tablis h the modulated picture or chrominance signal conditions under which spread- sprectrum and the interfering signal. Because the land-mobile radio (SS LMR ) systems can spectral bandwid ths of both the operate and determine the spectrum chromina nce and picture signals are of efficiency of such systems relative to the order of 2 MHz , a spread- spectrum conventional FM LMR . A service consis t signal with a lesser bandwidth would be ing of multiple independent networks, largely unfiltered in the TV receiver like the busines s land-mobile radio and , therefore , should produce service, was analyzed. The sys tems were interference similar to a conventional FM assumed to be operating in an urban land-mobile signal. (While it is true environment , transmitting voice signals that the spectral shape of an interferer with a modula tion bandwidth of 3 kHz . A can have an effect on the level of network consists of a base station with interference, this effect is generally of its associated mobiles , and the service second order compared to the power contains many net work s. ratio. ) In other words , the interference produced by a constant envelope, spread Th e analysis shows the following : spectrum signal (2 MHz bandwidth or less) should be nearly identical to that (l) Because an SS LMR network uses produced by a narrow-band FM modulated a channel 100 to 1000 times signal of eq ual power . For spectrum wider than a conventional FM spreads greater than 2 MHz , some LMR network with 25 kHz additional advant�ge can be expected spacing , there must be at least because of filtering by the video and IF 100 to 1000 times as many SS circuits.
12 0 c: 0'> (15 Q; .E 0 Frequency Offset, MHz Figure 1-4 . Measurements of minimum signal-to-noise ratio required for acceptable performance of TV inter fered with by FM interference (dashed lines) and FCC-recommended protection ratio (solid line) . 13 BW -Approximate RF Bandwidth, MHz 0 Random Sequence, TV/FM =34d8 )( Random Sequence, TV/FM =39d8 • PRN Sequence, TV/FM = 34dB :E 0 PRN Sequence, TV/FM=39dB LL -o c 0 E ;: u Q) 0. (/) -o 0 � 0. (/) c Q) Q) 3: Q) CD Q) u c � -� a 0.1 10 100 Direct Sequence Chip Rote, Mb ps Figure 1- 5. Estimates and measurements of interference potential of a spread-spectrum signal compared to a narrowband FM LMR interferer . ],4 networks operating on a channel On the other hand, suppose that all 24 for comparable spectrum networks were assigned to one SS channel. efficiency. Then U would be 10, using the definition of U in Table 1-5. The maximum process (2) An SS LMR service with multiple ing gain for the SS system would be independent networks must be 10 log (3 MHz/� kHz) = 30 dB; so R = -20. duplex; that is, the base The reliability from Table 1-5 is only stations and mobile stations about 0.51. For the spread spectrum must operate on different system to have a reliability of 0.97, we channels. Otherwise, an inter must cut U to 0.5 --a factor of 20. That fering base station will black is, in this case, conventional FM could out a wanted transmission from provide 20 times as many users with the a mobile to another base desired reliability as SS LMR in a fixed station. frequency band and geographic area. Frequency Modulation is therefore much (3) In an area near a base station more spectrum-efficient. antenna, mobiles from another network receive unacceptable An approximate analysis to be included in interference from the base the final report shows that, under station. The radius of the simplifying (but plausible) assumptions, area is proportional to the the spectrum efficiency of SS LMR ��stems separation between the base is proportional to (SS bandwidth) , station antennas. To avoid where a is between 1/3 and 1/2. This having many areas blacked out, shows that using a bigger processing gain all base station antennas must (larger bandwidth) would make the spread be located near each other so spectrum LMR system even less spectrum that they can share the efficient. blacked-out area. It is best if the base station antennas We conclude that spread-spectrum are all located on a single modulation is not as spectrum-efficient tall building or tower. as FM LMR in a land-mobile radio service containing multiple independent networks. Under these conditions, the probability of successful communication of a given The compatible SSB/HF Broadcasting study quality is given by was undertaken at the request of the Federal Communication Commission (F CC) to m-1 provide technical advice in preparing for P(communications/m,U) P(S/I 2:. R/k) the general World Ad ministrative Radio k=O Conference (WARC) to be held in 1979. In view of the extreme congestion in the HF Broadcasting bands, conversion from the where: P(A/B) means "probability of A .present double sideband (DSB) modulation given B," m is the total number of to single sideband (SSB) modulation would networks in the service, U is the total be desirable to achieve increased spec number of message hours per hour for all trum efficiency and minimize some kinds base stations, R is the required input of interference and distortion. The ITS signal-to-interference ratio, and k is was tasked to consider two approaches the number of stations transmitting at a toward this end: (1) the use of given time. The probability, P(k/U), was Compatible Single-Sideband (CSSB) computed using queueing theory, and P(S/I techniques as an intermediate step; and > R/k) was computed using the probabil (2) spectrum division between DSB and SSB istic Trade-offs Program described in modulation, with the SSB portion gradu last year's annual report. Table 1-5 ally expanding until complete conversion shows the probability of communications to SSB is achieved. as a function of U and R for large m. This table can be used to compute the Two systems of CSSB were considered, both number of SS LMR networks that could of which are based on the principle that operate successfully in an exclusive SS a single sideband signal with an LMR band. undistorted envelope can be formed from a signal with three components as follows: As an example, assume that we have 3 MHz of bandwidth for the service and want to provide an output S/I = 10 dB with E probability 0.97. Suppose that the s sin 2rrft +asin2rr (f+F)t average network has five mobiles, and they transmit for an average of five + (a2/4s) sin2rr(f+2F)t minutes per hour. At the normal FM LMR channel spacing of 25 kHz, 24 networks would each have their own exclusive channel with perfect reliability under the assumptions of Table 1-5. 15 Tab le 1-5. Probabi lity that S/I � R Given that at Least One Tran smitter is on. Mobi le-to-Base Tran smission in Urban Areas R .25 . 5 1 2 3 4 5 10 20 -30 .995 .991 .9 81 .959 .937 .910 .8 86 .7 84 .64 -27 .993 .987 .973 .941 .90 8 .874 .843 .711 .55 -24 .990 .9 81 .961 .916 .871 .827 .7 86 .633 .46 -21 .987 .973 .945 .886 .814 .773 .723 .544 .37 -1 8 .9 82 .964 .926 .849 .776 .710 .652 .456 .29 -15 .976 .951 .902 .805 .717 .640 .574 .372 .21 -12 .96 8 .937 .875 .75 8 .654 .567 .496 .294 .15 - 9 .960 .921 .845 .705 .5 87 .492 .417 .223 .11 - 6 .950 .902 .810 .64 8 .517 .421 .342 .164 I-' "' - 3 .940 .883 .776 .592 .452 .350 .276 .118 0 .930 .864 .741 .537 .390 .2 88 .21 8 .0 82 Notes : Assumes that the probabi lity that S/I � R is one if exact ly one tran smitter is on. All ba se s near the center of a circle with radius 30 km. Mobi le s are randomly located in the circle. Tab le wa s computed for radio frequency of 150 MHz, base antenna height = 200 m, n mobile anten a height = 1.5 m; but should be correct within a few percent for frequencies between 100 and 1000 MHz; ba se antenna height s from 50 to 400 m, and mobile antenna height s from 1 to 3 m. U = (N.Q,/60) m, where N is ave rage numbe r of tran smission s per hour by an individua l tran smitte r, 9., is the average length of a tran smission in minute s, and m is the total numbe r of transmitte rs. m Value s in table assume that U /m ! << 1. Thi s is true if m > 3U. where SECTION 1. 3 ADVANCED INSTRUMENTATION AND f RF carrier frequency SPECTRUM MEASUREMENTS F modulation signal frequency a = modulation depth � = a function chosen according to Needs for more realistic estimates of how the desired implementation, the spectrum is really used generate re O A standard set of measurements now includes a survey of usage in the fol lowing federal government commun ication bands: 30-50 MHz, 138-150 MHz, 162-174 MHz, 225-400 MHz, and 406-420 MHz . Radar bands are also part of the standard set 17 Figure 1-6 . The Radio Spectrum Measurement System (RSMS ) undergoing antenna calibration at the ITS antenna range . 18 15 Antennas and Noise Diodes RF /VIDEO BLOCK DIAGRAM 0.03·12 GHz of RSMS VAN �OMHzCAL! * Not Under Computer Control = ...... =z ==..... COMMUNICATION * N�""' �� TEST RECEIVER COMMUNICATION MEASUREMENT RECEIVER 0.5·12 GHz "'l"---� �J DETECTOR LOG VIDEO RF TUNER AMPLIFIER 10 MHz 0-18 GHz VIDEO BANDWIDTH * PRF FILTER _ __ WIDE__i BAND IF UNIT 0.01 -300 kHz 3MHz SSB, AM, FM PULSE TRAIN LOG AMP land 3M Hz BANDWIDTH IF DETECTORS SEPARATOR BANDWIDTHS in 1 ,3,10 STEPS LOG AMP TRANSIENT 0 ------� DIGITIZER ------8 BITS, 10 nS 2000 BYTE MEMORY G ating Contro1 1---·--- -- __..:::.. ___4___ __,______.....J Digital Data L to Computer DIAGNOSTIC CRT Digital Data -----.to Computer Figure 1-7 . Major elements of the Radio Spectrum Measurement System . 19 of measurements, includ ing the 1030-1090 identifying any unknown signals. MHz, 121�-1400 MHz , 2700-3700 MHz , 5250- 5925 MHz , and 8.5-10.5 GH z bands. Many Each year has seen some new measurement or all of the preceding bands have been hardware and software added to the RSMS measured in six large metropolitan areas for the purposes of mak ing better, across the United States . Measurements faster , more accurate measurements . Th is have been repeated in two of the areas , year improvements were made in two areas , giving a first look at the growth of apparently finishing a long chain of usage over a four-year period. In the evolutionary developments . Th ese areas- past year, measurements have been made in antenna system and communication band ten cities in the eastern half of the measurements--will be discussed in the U.S. , including extensive measurements at following paragraphs. Eglin AFB , Florida; Atlanta , Georgia; Norfolk, Virginia; and Washington, D. C. LMR Measurement Te chniques In addition to the standard usage mea Usage survey s are made in several surements , the RSMS has often been called land-mob ile radio (LMR ) and similar upon to help solve particular·�roblems . communication bands . In these The following examples will serve to bands, signals are usually narrow illustrate some of the system 's special band voice and the assignments are capabilities. We expect that the RSMS made according to a formal band will continue to respond to requests for channelization plan, with each special assi stance , especially when the channel separated from adjacent capabilities of the RSMS can be applied channels by a fixed amount, typi with a marked advantage over less cally 25 kHz. In theory, a usage elaborate systems . measurement is very simple--one merely has to tune to a frequency and measure how much of the time a The emission spectra of many dif signal is there . In practice , it ferent types of radars have been may be fairly difficult to make such measured as part of an effort to a measurement efficiently while determine trade-offs between assuring that the measured data is various techniques of spectrum accurate. Th e problems come mainly conservation in the radar bands. from the interaction of occasional These measurements have taken the large signals with the non-ideal RSMS to many parts of the u.s. to characteristics of pract ical observe prototype radars , crowded measurement system hardware . radar environments, and many older radars in various states of Large signals will cause the hard maintenance. ware to generate spurious responses , called intermodulation products , at The RSMS was used in a study of frequencies related to the sum and factors causing possible system different frequencies of various malfunctions in the very crowded harmonics of the strong signals . In 1030-1090 MHz air traffic control addition, noise on the measurement beacon (IFF) band . Fo r this work system local oscillator will show up the RSMS was tied to a large FAA as a band of signals adjacent to any computer which processed air strong signal. Th ese spurious route data frQm beacon signals, responses will be measured by the while the RSMS simultaneously system as though they were real measured the signal environment . signals in the environment. By correlating the signal Software processing of the measured environment with computer data to separate the spurious sig processing malfunctions , the RSMS nals from the real signals is often was able to provide some data on extremely difficult, since the the causes of some malfunctions , measured data on the large signal as well as to help estimate the population is usually not adequate amount of improvement with to reliably calculate quantitative various fixes . amplitudes for the spurious responses . NASA asked for help in locating the cause of occasional inter Al though we attempted to remove ference to reception of deep spurious signals from recorded data space signals at its Goldstone with software processing in some of communication site. Automatic our early LMR measurements , our surveillance programs were philosophy has shifted strongly devised for the RSMS and operated toward real-time screening and on a 24-hour/day basis for five analysis of the data. The cost of weeks. Th ese programs included taking massive amounts of data with many features like automatic computer-controlled systems is so direction finding to assist in small that it is often practical to 20 merely throw away the data if there these periods is simply ignored. is reason to suspect that it may be Because strong signals might occur contaminated with spurious responses on frequencies that ate not measured Accordingly, the RSMS measurement or at times when other frequencies techniques now include several in the band are being measured, one precautionary tests which are cannot depend on the regular mea continually operated on a real-t ime surement system to provide reliable basis to determine whether data peak signal power data. We use a might be contaminated by spurious separate RF wideband detector , which responses. Fo rtunately, the most looks at the entire RF bandpass all important test is a simp le one , the time , assuring that no strong since the po ssibility of spurious signals will be missed. To simplify responses is directly related to the measurement software ; the peak peak power incident on the active value of a signal during a five components of the receiver. second scan is held in a peak detector and me asured only at the Figure 1-8 shows many of the pre end of a scan. If a strong signal cautions which are taken to insure is seen, all of the data for that measurement qual i ty. Th ese scan is deleted. precautions fall into three main areas : 1. High performance Th is combination of hardware and measurement equipment , des igned to software has allowed us to gather have few spurious responses; 2. uncontaminated data at many sites choice of a measurement environment which would have been unsuitable for to avo id most strong signals; 3. measurements with a less capable tests which discard possibly wrong system. In a recent series of LMR data if 1. or 2. is not sufficient. measurements , for example, almost One should note that all three of 25% of the data was deleted because these precautions are inter-r elated of strong signals, but we believe compromi ses. Fo r example if one that the data which was retained is could build ideal measurement completely free of spurious respon recievers (#1) , it would not be ses and accurately represents the necessary to worry about #2 or #3. signal environment. Similarly, with a sufficiently benign measurement environment (#2), Antenna Systems it wo uld not be necessary to employ #1 or# 3.. In the real world, none A second area of improvement is the of the precautions can be made to RSMS antenna system, wh ich has been work sufficiently well to do the job modified to allow considerably mo�e by itself, and all mu st be used in effective direction-of-arrival combination. measurements on unknown signals (Figure 1-9). Th e RSMS was designed Careful selection of a measurement originally with 1-12 GHz cavity site , avoiding local transmitters, backed- spiral (CBS) antennas and is the first step in assuring a .1 5-4 GHz conical helix antennas in relatively easy measurement environ sets of four (see Figure 1-6). ment. Good RF bandpass filters Since these antennas typically have eliminate out-of-band strong signals 70-90° beamwidth, the set of four and notch filters can be used to could be aimed with 90° between each eliminate a few strong, relatively antenna to give fairly complete ° continuous , in-band signals. Th e coverage for 360 . Two sets of four high performance measurement were used to get right-hand and equipment is a subsystem designed left-hand circular polarization. and built by ITS with capabilities These antennas have served well in in selected LMR bands below 500 MHz our earlier measurements and gave a (labeled "communications measurement very primitive direction-of-arrival receiver" in Figure 1-7). Th is capability (by noting which antenna specialized system makes accurate received the signal best). measurements over an ins tantaneous 110 dB dynamic range (-115 dBm to -5 The RSMS also had a roof-mounted El dBm ) with an 18 kHz rectangular Az pedestal carrying a 36", 1-12 GHz bandw idth that is down more than 80 dish antenna suitable for more dB 25 kHz away. Even in this state precise direction-finding , as well of-the-art system, signals larger as to isolate a signal for mo re than about -40 dBm can cause detailed analysis. The dish was intermod responses above system very useful , but clumsy, turn ing no ise, which would masquerade as only at one very slow rate (1° - real signals. second ) and turning only + 2006 before needing to be stopped and For the occasional signals stronger reversed. In addition , its pos ition than -40 dBm, data measured during on the roof of the RSMS was often 21 Antenna site chosen with care , away from local transmitters , but near electricity , telephone , roads, with good coverage . Bandpass filters remove all signals outside band of interest , minimizing number of strong signals . Op tional Notch filters used inside bandpass Notch to eliminate a few local signals , Filters if necessary. I 1 �rearnp Wide-dynamic-range preamplifier in creases system sensitivity with min ima l decrease in overload levels. Power-splitter provides signal for RF overload detector., IL.O. generated with accurate& fre qu ency low side bands + 20 Local High level mixer and dBm Osc illa tor__±__2_Q_d.Em.£> L.O. reduce spurious responses. j RFBroadband. 18 detector kHz80 BW crystal25 filter is more RF measures than dB down kHz away , re total ducing adj acent channel response. overload signal in Detector RF band "-.(f),. 10-450pass �1Hz) 110 dB 110 dB range log amplifier al Holds max Log lows simultaneous measurement of imum signal Amp large and small signals. leve l until end of scan �----(�5�s�e�c��-----�'� Samples maximum signal at end of each scan to determine if data is good . 40 ADC make s measurements on each channel , which are processed to eliminate impul sive noise . Computer Controls system, analyzing data in real time after determining that data contains no spurious responses . 1-8. Figure Special design precautions to insure high quality measurements . 22 1-9. RSMS Figure antenna array . 23 below the height of nearby build Th e RSMS ee chno logy has led to the deve ings , trees , etc. , wh ich blocked its lopment of a series of related instrumen view in several directions . Many tation systems . One such development is signals disappeared before th is slow the Ai r Fo rce Multiple Re ceiver System and uncertain direction-finding pro ( AN/MSR-T 1) • cess could be made to give an answer. Th is program, under the Air Fo rce Systems Co mmand , involves the development , Recent modificat ions to the RSMS acquisition, integration , and test ing of antenna system use the cavity a first article pre-production multiple backed-spiral antennas for receiver system, des ignated the ins tantaneous direction-finding of AN/MSR-T l. Th e system is being acquired moderate precision , supplemented by to meet the electronic warfare (EW) a fast-moving dish antenna at the training and testing requirements of the top of the tower . Us ing the CBS Ai r Fo rce . The purpose of the AN/MSR-T l antennas to find approximate is to provide measurements for evaluating direction-of-arrival , the operator the operational performance of ground can rapidly find a more exact based threat radar systems and the bearing using the dish antenna . A response of au tomatic and manual airborne PIN-diode sw itch allows the system electronic co unter-measure (ECM) systems . to rapidly measure the signal on each of the four CBS antennas in a The EW training exercises are conducted set. System software controls the at Air Fo rce ranges equ ipped with mu lti switch according to operator ple threat systems , which are directed on selected parameters , gathering peak aircraft that come within operating and average signal ampli tude range. Th e radar threats emit simulta measured at each of the four neous signals at different frequencies in antennas . For example, measuring the range 0. 5 to 18 GHz . Th e aircraft, for 10 ms on each antenna before equipped with multiple ECM emitters , sw itching to the next and continuing responds to each threat emission with a switching for five seconds would signal containing noise or complex modu reliably measure a radar with a lat ion waveforms designed to five-second rotation period and any inhibit/degrade/deceive the target PRF more than 100 pulses/second . acquisition/track ing capability of the The relative amplitude is compared threat radar receiver . Du e to cost limi to known receiving antenna patterns , tations , the threat radars do not include and a direction-of-arrival is receivers which co uld be used to measure immed iately calculated. Al though and evaluate the airborne ECM responses; the bearing is typically accurate to therefore, the AN/MSR-T l is utilized to ° only 10 , this is often sufficient determine the operational capability of to identify the source of a signal, the ECM systems and provide maintenance and the process is very rapid. An personnel with reliable and sufficient identical procedure could be data to identify malfunctioning implemented with the conical helix equipment. antennas to extend the fast direction-finding- capability down to Th e program was started in February 1976. 150 MHz . However, the antenna The mu ltiple receiver design was com patterns are not as uniform on these pleted in May 1977 after extensive test antennas , and considerably larger ing of new technologies for receivers directional errors wo uld be expected (wideband 0.5-18 GHz tuners with 500 MHz to occur. IF bandwidths) and signal processors (500 MHz bandwidth Bragg cell optical techni When greater accuracy is needed , the ques with 1 MHz frequency resolution) 1-12 GHz dish antenna can be used . which were considered essential The new antenna pos itioner allows requirements for the first article pre the dish to be placed at the top of production of AM/M SR-T l. Procurement was the antenna tower , where it is more initiated and delivery of all hardware free from local obstruction. Th e was completed in July 1978. Integration dish can be rotated at up to + 20° was completed in August 1978, and exten per second with a digital reado ut sive testing is now underway at the accurately showing po inting direc USAF/SAC Strategic Tr aining Range (STR) tion. A rotary joint and slip rings in La Junta, Co lorado. Figure 1-10 is allow continous rotation, as well as an aerial photograph of the SAC/STR site noise diode calibration through the showing the various ground-based threat rotary joint . Though not yet systems and AN/MSR-T l in their implemented , it is planned to allow operational locations . the po inting direction to be read into the computer system via an IEEE The operational frequency range of the 488 bus, allowing direct plots of AN/MSR-T l is 0. 5-18 GHz . The system signal ampl itude vs . direction-of co nsists of four 0. 5-18 GHz tuners (one arrival . with a 500 MHz IF bandwidth and three 24 "' U1 Figure 1-10. SAC Strategic Training Range for Electronic Warfare , La Junta, Colorado . with a 20 MHz IF bandwidth ), a spectrum Al though the TAC/SAS design is similar to analyzer receiver (3 MHz bandwidth), the AN/MSR-Tl, it will be deployed for appropr iate demodulations signal proces different appl ications in EW test and sing units (Instantaneous Fo urier exercise evaluation . Its primary appl i Transform optical processor , microproces cation is the evaluation of ECM emissions sors , compu ters , special function from airborne fighter platforms when hardwired units ) and data/d i splay/s torage stimulted by widely-spaced (several units . Al l hardware is configured in a kilomters) ground-based acquisition and self-propelled veh icle with non track ing radars . directional and directional antennas mounted on the vehicle roof . Th e az imuth The system is fully automated and is and elevation pos ition of the directional designed to cover the frequency range 500 antennas are compu ter-controlled using KHz to 18 GHz and cons ists of antennas, slaved tracking commands from a local receiv�rs , compu ters , signal processors , threat IFF target tracking system. data display/ s torage units , and support equipment . It is housed in a self Th e system is fully automated and con contained, self-propelled vehicle with tains extensive software for command and internal power sources for remote opera control of all units and measurement/ tion (Figure 1-11 ) . Th e antenna system analys is routines . The ECM equipped includes an electro-optical television aircraft, upon entry into the range tracker system to provide automatic designated airspace , are subjected to tracking of a target aircraft at a range various realistic threats which are to be of 20-25 nautical miles . The receiver countered by specific signals that are sub-system contains two receiver sets. generated to jam or deceive the threat On e is a wideband tuner covering the receiver and operator . Since the threats range 500 MHz to 18 GHz with a 500 MHz IF do not have receivers , the AN/MSR-T l is bandwidth , and the second is a spectrum employed to receive and analyze the air analyzer receiver covering the range 50 borne response . Th e ECM signals are KHz to 18 GHz . The wideband tuner works evaluated by precise measurements of the with an IFT optical processor that has a time of response, frequency of response, 500 MHz instantaneous bandwidth and fre and all signal characteristics . The quency resolution of 1 MHz . Its purpose threat emissions and their effective is to scan or mo nitor all frequency bands countermeasure signals are classified, of interest to detect onset times of but involve pulsed waveform patterns transmissions which are to be measured. which produce range gate pull-off and A read-out is obtained indicating velocity gate pull-off target deception activity and frequency for hand-off to techniques as well as barrage and spot the spectrum analyzer receiver for no ise jamm ing modes . Airborne ECM sys detailed signal processing of the tems are either manual or automatic detected emissions . depending on the aircraft conf iguration. Data are output to the aircrafts home Procurement of all hardware items has base for aircrew training proficiency been completed and integration is under rat ings and identification of malfunc way . So ftware routines for command and tioning airborne ECM equipment . control are essentially complete, and special software measurement routines for Air Fo rce acceptance testing began in -TAC applications are in process . Th e September 1978 and is to be followed by a system is to be compiled by October 1978. six-month Air Fo rce user (SAC and TAC ) Acceptance tests are planned during Operational Test and Evaluation (OT&E ) No vember 1978 with deployment to the period . The purpose of the extensive Ne llis EW range complex scheduled in user OT&E is to identify design problems De cember 1978. and final ize specifications for the pro duction of similar units. Emphas is is to Transpor tabl� Au toma ted Electromagnetic be placed on trade-off of capabilities to Measuremen� Sys tem (TAEMS ) reduce complexity and cost in production units and still meet the essential use requirements . TAEMS is a system being developed for the U.S. Army Communications Systems Ag ency A related program is the Ai r Fo rce Signal to be used by the Communications El ec Analys is Sys tem. Th is program, under the tronics Engineering Installation Ag ency Tactical Air Command , 'l'a ctical Fighter CEEIA for field measurements to provide a Weapons Center Ra nge Group (TFWCRG) , reliable data base for EMC analysis. Ne llis AFB , Nevada, is to provide an Th is includes measurements of radio interim electronic warfare (EW) Signal spectrum usage for the management and Analysis System (SAS ) capability until engineering of military communication production units of the AN/MSR-Tl become systems and for the evalution of electro available in the 1982 time frame . The magne tic energy levels at various interim SAS design is based upon portions worldwide sites . Th e emphasis in FY78 of the AN/MSR-T l. has been the operational enhancement of the system including the development of a 26 Figure 1-11. The TAC/Signal Analysis System (SAS ) for electronic warfare (EW) test and exercise evaluation . 27 remote extension which allows the opera to-use systems that still provide digital tion of the down converter/antenna records of the obs ervations and perhaps subsys tem some 300 feet from the TAEMS . some de gree of automatic control . One such project requires the development of There are two four-wheel-drive special a Manportable EMC Measurement Sys tem. purpose vans that make up one system. This program is in its third ye�r under One van is the Data Acquisition Van (DAV ) sponsorship of the u.s. Army , Communica which houses the computer-cont rol led EMC tions and Electronics En gineering measur ement system. Th e other van is the Ins ta llation Ag ency (CEEIA) . Maintenance and Ca libra tion Van (MCV ) which houses maintenance , ca libration , During this year , the microprocessor and other ancil liary equipment . Another development system was upgraded to FY78 project in the area of application include a CRT terminal , a high-speed line enhancements was to develop the required printer , and a one-half inch magnetic computer grid interface and operating tape recorder . Th ese improvements allow software to permit automa ted operation of much easier , faster , and more accurate the equipment in the MCV and DAV. Al ong prog ram development . The industry stan with this effort wa s the development of a dard half-inch magnetic tape also will voltage tuned tracking filter and allow compatibility of da ta between . saturation detector to augment the ba s1c various data analysis systems (computers ) TAEMS capabilities with respect to pre such as the CDC 6000. selection and mixer saturation be low 500 MHz . Current work is being undertaken to improve the field units by providing Work has also started on a pe rformance shock mounted ruggediz ed ch assis . Th e verification test set for the automated development system is being improved with receiver system. Th e test set is to be the addition of a 1977 ANSI Standard used to validate key prformance para Fortran compiler . meters and to periodica lly ca libr ate the system. Ba sed on previously es tablished Th e Automa ted Field Intensity Measurement verification limits , a routine wil l also System Project is a further effort to be configured to indica te to the operator provide small, modest-cost spectrum of the sys tem when any of these key ins trumentation. Th e system wil l be used performance parameters are out of to make ordinance and personnel hazards specification and when corrective measurements . Th e field intensity ca l ibra tion or maintenance needs to be receivers used by the system are initia ted. automatically ca librated. Th e operator then specifies frequency scan width , Th e data obtained from verification receiver bandwidth , detector , etc. to the measurements wil l be a valuable record of system control ler. Th e controller sets system performance and can be compared to the specified parameters , collects the subsequent tests to dis cover trends in measured da ta, stores it on magnetic overall performance . tape , and computes statis tics of the collected da ta . Th e system has be en Key system performance parameters to be designed to operate unattended for long checked are: time periods (24 hours , one week , etc. ), depending upon how often data are to be 1. Tuning accuracy col lected. Th e ma jor contribution from 2. Selectivity this project is the development of appli 3. Tune/measure time cation software which could be utilized 4. Sensitivity by other agencies having similar 5. Frequency respons e ordinance hazards me asurement 6. Re l ative amplitude accur acy requirements . 7. Intermodulation accuracy 8. Isolation The U.S. Army Combat De velopment Engi 9. Absolute power ca l ibration neering Command (USACDEC) at Fort Hunter Liggett , Ca lifornia , is increasingly Performance verification test routines dependent upon radiating telecommuni will be cons tructed to verify the perfor cations systems to locate and monitor the mance of various subsystems as we ll as locations of participants in mock the overall system. Th ese subsystems military exercis es . Th e primary system include such units as the multimode currently in us e is the Range Measurement detector , wideband IF section , power System (RMS ), which utilizes a large me ter and source control . number of interrogators and beacons to locate the participants . When an The instrumentation discus sed so far has interroga tor malfunctions and begins been large and sophisticated, both in transmitting a continuous tone or when a design and operation . A compe lling need local or remote source interferes with exis ts for automation and new technology the RMS operation , the position da ta can in spectrum measurements at the other end be lost. of the scale - small, lightweight, easy- 28 To avoid costly losses due to interfer tained to one of the folowing groupings : ence , a Spectrum Mo nitoring Unit is being designed and built which meets the 1) tutorial follow ing requirements : 2) applications 3) interference rejection a) capable of observing radio 4) spread spectrum system studies signals over the air at 5) multipath propagation frequenc ies betwen 30 MHz and 6) direct sequence/f requency- 18 GHz with emphasis on the RMS hopp ing/ch irp techniques frequencies near 918 MHz; 7) modulation/demodulation 8) synchronization/tracking b) capable of direction-finding 9) codes for spread spectrum. for rapidly and accurately locating interfering sources , On e task of the present project is to especially those around 918 make measurements of the interference MHz ; effects of spread spectrum signals on narrow-band FM . Th e spread spectrum c) capable of full operation with signals are generated by passive surface minimal training by field acoustic-wave devices and by active personnel ; pseudorandom noise generators . On e concern is whether spread spectrum system d) capable of remo te area opera can share frequency bands with the tion in a four-wheel drive channelized FM system. vehicle by a single operator/ driver; and On e of the most comprehensive instrumen tation development and measurement e) capable of self-calibration and projects deals with assessment of the digitally-controlled operation . Interference Potential Between CATV and Ai r Tr affic Co ntrol Systems operating-in The Spectrum Monitor ing Unit will utilize the 108-136 MHz bands. a microprocessor-control led spectrum analyzer with directional, omnidirec Le akage from a coaxial cable system tional, and steerable antennas to detect carrying CATV signals at frequencies used and locate signals or interference . for air navigation and control poses an Because the communications and displays interference potential studied by ITS for are remoted from the operational area of the FCC . A series of flight tests were the vehicle to the driver's pos ition, one performed to measure the signal levels person will be able to drive the vehicle radiating from operating CATV systems to plus direction find and locate an aircraft ins trumented to probe the interfering source . airspace for RF signals above the CATV systems . The Spectrum Monitoring Unit will upgrade the USACDEC spectrum management capabili Figure 1-12 shows an FAA aircraft used in ties for making spectrum occupancy the measurements and Figure 1-13 shows surveys , for improving spectrum utiliza the ITS instrumentation mo unted in the tion, and for insuring that local aircraft for the measurements. equipments are operating within specifi cations and allocations for frequency , The signals at 108. 05 MHz or 118.0 MHz bandwidth , etc. were introduced at the head end of the CATV system while the aircraft flew a Along with the development of new instru grid pattern over the CATV system and mentation , NTIA/ITS appl ies this recorded the RF signal leakage with a equipment in the measurement of various very sensitive , narrow-b and receiver . At spectrum properties . A series of labora the same time , FCC ground crews measured tory measurements were made iQ support of the leakage at ground-level over a grid a number of other projects , most particu pattern along the CATV system. larly one to define Spread Spectrum Interference Characteristics. Th is project has been a joint program in cooperation with the FAA , several CATV The purpose of this project has been to operating companies , and the FCC . Ground study spread-spectrum techniques to measurements were made by the FCC Field determine if they can be efficiently and Op erations Bureau . Th e FAA Na tional effectively applied to communications , Aeronautical Facilities Experiment Center specifically land-mobile radio; spread prov ided flight test aircraft and other spectrum has its origins in radar, navi support. gation, radio location, and deep space communications . An NTIA Special The measurement results will be used by Publication entitl�d, "Spread Spectrum: the FAA , the CATV industry , and the FCC . An Annotated Bibli6graphy" , NTIA SP 78-l, was published to alert interested readers about spread-spectrum reports which per- 29 w 0 Figure 1-12 . Aircraft used for measuring CATV radiated signals. Figure 1-13. ITS developed instrumentation , as installed in flight test aircraft for acquiring data measured as part of ' the CATV interference evaluation proj ect . CHAPTER 2. SYSTEMS ENGINERING Project outputs are also being coordinated AND EVALUATION with the Amertcan National Standards Institute , which is involved in the The objective of this program subelement development of industry standards for is to provide telecommunication system data communication performance ; with the definition, designs , and consulting ser National Bureau of Standards , which is vices to meet users ' requirements through responsible for the Federal Information me asurements , analyses , and evaluations Processing Standards (FIPS ) program; and and to develop and dis seminate performance with the Federal communications Commis criteria . The resultant performance sion , which is considering the establish criteria and measurement methods are ment of performance standards for common used by Federal agencies in planning , carrier services under its Quality and designing , specifying , procuring , leasing , Reliability Inquiry (Docket 18920) . and operating telecommunication systems . The project elements described below Figure 2-1 illustrates the overall generally deal with existing or proposed organization of the Data Communications telecommunication systems and/or sub project . Maj or project outputs will systems . Section 2.1 addresses work consist of three related Federal Standards : relating to communication services engineering. Section 2.2 presents Federal Standard 1033 - defines projects oriented toward satellite user-oriented , universally applicable communications . section 2.3 summarizes performance parameters for specifying the terrestrial radio system performance data communication system perfor efforts . Section 2.4 deals with radio mance . channel simulation and radio system performance standards , and Section 2.5 Federal Standard "l033A" - will presents related work in fiber optical define standard mea surement methods communications . to be used in conjunction with the standard parameter s in assessing SECTION 2.1. COMMUNICATION SERVICES delivered performance . ENGINEERING Federal Standard "l033B" - will Some of the systems technology projects define standard performance classes relate to established or planned communi and requirements for interconnection cation services . The services are of dissimilar networks . either offered or leased by mission agencies , and the engineering described The Data Communications project is here relates to the evaluation , perfor comprised of three ma jor project activi mance criteria , or new technology re ties : Technology Applications (consist quired for efficient, cost-effective ing of three consecutive phases ), Statis procurement , offering , or establishing tical Analysis , and ARPA Network measure these services . Five projects are ments . The Technology Applications described ; namely : Data Communications , activity serves as a focal point for Electronic Mes sage Services , Access Area development of each standard . Final Digital Switching Systems , AM Stereo results of Technology Applications Phase Broadcasting , and Maritime Administration l have been presented in a 2-volume NTIA Assistance. Report (Seitz and McManamon , 1978; Kimmett and Seitz , 1978) . Interim Data Communications . There is a growing results of this activity have also been need within the Federal Government for presented in two articles published uniform means of specifying and measuring earlier in FY 78 (Seitz and McManamon , the performance of data communication 1977a; Seitz and McManamon , 1977b) . systems from the point of view of the digital services delivered to the end The second major Data Communications user . NTIA 's Data Communications project project activity, Statistical Analysis , has been undertaken to meet that need is aimed at developing confidence limits through the development of Federal and sample size requirements to stand Standards specifying universally applic ardize measurement of the selected able , user-oriented performance param performance parameters. Prior work in eters and measurement methods . The this area has addressed the measurement project is being conducted in cooperation of bit error probability , and has produced with the Federal Telecommunication definitive new methods of assessing the Standards Committee (FTSC) , an interde statistical precision of such measurements . partmental standards group organized by FY 78 efforts have extended these results the National Communication System under to the block-oriented accuracy parame the auspices of the General Services ters (Crow , 1978) ; and have laid the Administration (GSA) . After approval , foundation for the development of confi the standards developed under the project dence limits for the time delay param will be promulgated by GSA , and will be eters. mandatory for use by all Federal agencies in specifying the end-to-end performance of data communication systems and services . 33 NTIA /ITS (Program Management) FTSC FCC, ANSI (Program Objectives) (Related Work) FS 1033 STANDARD PARAMETERS I - - -- �------� I FS '1033A' I l STANDARD MEASUREMENT METHODS \ 1 L ______------� I T FTSC ------FCC, ANSI I ""' i / I , ..--- � / --J" I I I TECHNOLOGY \ I "------{ APPLICATIONS f-.-----/ \ (PHASE 3) J Legend "'---.. / - Completed Work ---- __.. / -- Work in Progress I Future Work ______��- 1 1 FS '10338' I INTERCONNECTION PERFORMANCE STANDARDS I L ______j. 2-1. Figure Data communications project overview . 34 The third major Data Communications Figure 2-3 is a histogram of individual proj ect activity , ARPA Network Measure access time values measured on the ARPA ments, has been undertaken to substantiate network (Payne, 1978) . The ab scissa the theoretical results of the first two represents total access time in seconds , activ ities by means of actual network and the ordinate indicates the total performance measurements . Values for number of access attempts encountering five of the selected performance parameters each particular delay . Each measured were measured during this fiscal year value represents the total elapsed time (Payne, 1978) . between operator typing of a CONNECT TO request (initiating the transaction) and Figure 2-2 illustrates the specific transfer of the first byte of information parameters selected for inclusion in from user storage to the Network Control proposed Federal Standard 1033 . The Program (initiating user information parameters are organized in a matrix transfer) . This histogram is typical of form, to associate each parameter with a the results being produced in the ARPA corresponding communication function and network measurements activity ; collec user concern (or "performance criterion") ; tively, these results are demonstrating as an example, the parameter Access Time that the performance parameters specified expresses performance of the access in proposed Federal Standard 10.33 can be function relative to the user 's concern measured in a complex , multi-user tel e with ef ficiency or "speed ." processing network. A total of 26 parameters are specified The real importance of the Data Communi in the standard , including 19 "primary" cations project lies in its substantial parameters, 3 "secondary " parameters, cost savings potential . An independent and 4 "ancillary" parameters. The National Research Council committee formed primary parameters provide a detailed to advise the Office of Telecommunications description of performance by focusing on program priorities has estimated that a on a relatively short observation 20% reduction in total Federal data com period; as an example, the parameter munications costs could be realized Block Transfer Time expresses the end through the promulgation of an efficient to-end delay expected during the transfer method of selecting the right system or of an individual user information block. service for a given user need - a poten The secondary parameters provide a more tial savings in excess of $400 million per macroscopic view of performance, closely year by the mid 1980 's. The Federal associated with the traditional concept Standards being developed under this of availability ; as an example, the project will provide the essence of such a parameter service Time Between Outages method . is essentially a sampled measure of the availability parameter Mean Time Between USPS Electronic Message Service System. Failures . The ancillary parameters During FY '78 the ITS has continued with provide a quantitative means of expres on-going tasks , completed work star ted sing the influence of user performance during the past fiscal year and under delay on the primary parameter values ; taken new efforts in the development of as an example, the ancillary parameter an Electronic Message Service System User Access Time Fraction expresses the (EMSS) for the U.S. Postal Service average proportion of total Access Time (USPS) • This project now constitutes that is attr ibutable to user access Phase VI of the NTIA/ITS continuing delay . support of technical studies for the USPS . The effort continues to provide To eliminate the possibility of misinter technical support, analysis , documenta pretation , each selected parameter is tion , and review for the EMSS Definition defined in two ways : and Evaluation (D&E) program . l. Axiomatically , by reference to The ITS support again provides l) anal a "pie" diagram or .sample ysis reviews and recommendations concern space representing the possible ing reports and documents developed by a outcomes of an individual USPS contractor and 2) technical consul "trial performance" of the tation to the USPS regarding telecommuni associated communication cations problems . Attendance and partic i function . pation at reviews and briefings contin 2. Hathematically, by reference to ues as part of ITS support to the USPS . parameter definition flowcharts and equations . In tasking initiated during a previous ITS/USPS agreement , three final Er1S S The parameter def inition flowcharts and candidates were selected from fifty-two equations provide a detailed procedure for system alternatives that had been identi calculating performance parameter values , fied. Twenty-eight of these candidates given a measured sample population of were developed by the ITS in cooperation performance trials . with the USPS . The three candidates will be studied in more detail using a network costing and parametric analysis 35 PERFORMANCE CRITERION FUNCTION I EFFICIENCY I ACCURACY RELIABILITY / • ACCESS DENIAL USER ACCESS TIME ACCESS · ACCESS TIME · INCORRECT ACCESS PROBABILITY I I PROBABILITY FRACTION BIT MISDELIVERY PROBABILITY • · BIT LOSS BIT TRANSFER · · BIT ERROR PROBABILITY BIT TRANSFER TIME PROBABILITY I I • EXTRA BIT PROBABILITY BLOCK MISDELIVERY PROBABILITY , • . BLOCK LOSS BLOCK TRANSFER . BLOCK TRANSFER TIME BLOCK ERROR PROBABILITY PROBABILITY '• EXTRA BLOCK PROBABILITY I I w I I 0'1 . BIT TRANSFER RATE MESSAGE TRANSFER • BIT RATE EFFICIENCY I • BLOCK TRANSFER RATE • BLOCK RATE EFFICIENCY DISENGAGEMENT I.DISENGAGEMENT TIME Pr imary Parameters Secondary Paramet,ers ,',' ,, Ancillary Parameters 2-2. Figure Summary of selected performance parameters . 30 --.------ 25 20 (f) I- a.. ::E LU I- I- <{ 15 (f) (f) LU u u <{ w -.J 10 5 - - - · ·'"'"'"'"'"'"' : : :-:- - -: ':"' · · · · -·- ·-·. -:-:- -:,:-:- · ·.-.-.,.,.,.:-,· -·-·.·.·.·.· · · ·.·.·.·.·.·-:-:- : -· · · · · ·.-:- : · · · · · · · ·.·. o r::::-: : : ;:-. .; ;:: ; -· 1 1 ·.-.-., I 1 � r l 6.6 6.8 7.0 7,2 7.4 7,6 8.4 ACCESS TIME IN SECONDS FREQUENCY HISTOGRAM 2-3. Figure Access time histogram. computer model. Eventual selection of a over $2 billion. One might pause in final EMSS candidate will be based in considering this candidate . However , part on these analyses . the issue of public service enters the picture here . The number of stations The character istics of the three candi increased from 25 to 1500 . These sta dates that were selected are summarized tions offer a vari ety of services such in Table 2-la and 2-lb . Start , inter as customer service and faster speed of mediate , and mature levels of development me ssage delivery . The EMSS then becomes are shown for candidates A and B, while a trade-off between costs (hidden and only the mature level is shown for apparent) and customer service and candidate C. Three of over 90 input convenience. parameters to the parametric analysis computer model are shown across the top Other work concerned i·tself with an of the tables while the other headings accuracy-cost study of the EMSS wh ich are for some of the results of the mu st begin with the message as it leaves analysis . The three input parameters the sender and ends with the message as are Annual Volume (Billions ), Number of it reaches the recipient. Sources of Stations , and Number of Public Terminals inaccuracy for digital data such as (Table 2-la) . Average Letter Size telecommunications and magnetic media , (Bits) and Size of EMS Staff (Table 2-la) as well as paper media were taken into are computed in the course of the account . The sources included message algorithm . Stations are defined as error at input, output , and a s the message facilities which provide for customer proceeded through the system . Ac curacy , access as well as input , output, and cost equations and a computer program processing capability . Stations may that implements cost-accuracy trade-offs have different input and output conver are reported in OT Technical Memorandum sion capability for magnetic and paper 78-248, "Accuracy-Cost Study for the media, and telecommunications . USPS Electronic Message Service System" by M.J. Miles . Public terminals are defined as owned or leased by the USPS and are intended for Another contribution was the resolution access to the EMSS by the general public. of message size conversion factors used They are distributed for easy access in in the EMSS parametric analysis computer post office lobbies , public buildings , model. The number of bits per me ssage shopping centers , and so forth . However , is determined by factors such as the public terminals would only have an message origination and destination input message capability using facsimile (e .g. , business-government, household), and address entry by keyboard . The message function (e . g. , transaction , service would be limited compared to correspondence) , address , and alphanumeric EMSS stations . and graphic characteristics . The annual message volume along with the Under current contracts with the USPS , number of EMSS stations and public the ITS is involved in 1) Development of terminals show the growth of EMSS for EMSS Planning Factors and 2) EMSS Network Start, Intermediate , and Mature candidates . Planning Support. These are described A time frame for this growth is the here . subj ec·t of future work . The development of EMSS planning factors Two of the important results are Cost/ involves systems and service planning as 1000 Messages and Cost/Megabit, both follows . do llar figures (Table 2-lb) . In parenthe 1) Development of System Planning ses in those columns we also show the Factors . Necessary plans , telecommunication costs which are a planning factors , and support fraction of the message cost. The data for the EMSS study are message cost computed in candidate A is being provided . Assistance is 2.5¢ per me ssage , while the cost of being given to the USPS in the transmitting that message is approximately development of a system plan 0.4 ¢. Note that in candidate A. message that will lead to a work size increases dramatically (more than statement for the EMSS at doubles}, the number of stations and inception of capabili·ty (IOC ) . public terminals that serve the customer An example of systems planning also increase, but the cost per message factors involved are the remains constant during intermediate and interfaces existing between mature phases. EMSS stations , existing USPS stations , and USPS customers The message cost in candidate B ranges (Figure 2-4) . A viable EMSS from 1.5¢ to double that as message requires that these interfaces volume goes from 6.5 billion to 35 are compatible . Another billion pieces . The telecommunication planning factor implied in costs increase from �. 23¢ to .46¢ per this figure is the terrestrial me ssage . Also the investment costs satellite or hybrid networks start at $194 million and escalate to 3.8 Table 2-1a . 3 EMSS CANDIDATES ANNUAL AVERAGE NUMBER SIZE NUMBER VOLUME LETTER OF OF OF PUBLIC CANDIDATE (BILLIONS ) SIZE (BITS ) STATIONS EMSS STAFF TERMINALS A - START 9.9 31 ,950 76 4,021 917 A - INTER- MEDIATE 19 .8 31 ,960 150 9,177 1,986 A - MATURE 41.6 66 ,820 360 19 ,816 3,480 B - START 6.5 29 ,360 25 1,062 0 B - :tNTER- MEDIATE 17 .6 21·, 900 360 5,666 795 B - MATURE 35.0 54 ,500 1,500 22 , 901 2,427 C - MATURE 24 .1 35, 750 99 4,142 7,100 Table 2-1b . 3 EMSS CANDIDATES COST/1000 TOTAL TOTAL PRODUCTIVITY ME SSAGES COST/MEGABIT INVESTMENT OPERATING COSTS MILLION MESSAGES CANDIDATE (DOLLARS ) (DOLLARS ) ($ MILLIONS ) ($ MILLIONS PER PERSON-YEAR A - START .25 (4) 0.78 (0.12) 665 180 2.46 A - INTER- MEDIATE 26 (3.35) 0.82 (0,10) 1,375 381 2.16 A - MATURE 26 (3.52) 0.38 (0.05) 2,615 801 2.10 B - START 15 (2.36) 0.49 (0 .08) 194 77 6.12 B - INTER- MEDIATE 26 (3.07) 1.20 (0 .14) 1,335 333 3.11 B - MATURE 29 (4.62) 0.52 (0 .09) 2,260 787 1.53 C - MATURE 21 (6.96) 0.59 (0.19) 1,580 348 5.82 39 SYSTEM EMSS,- --- - INTERFACE / ------...... / ', I \ I \ USPS I I I STA I EMS S SYSTEM USPS STA I USPS I : I \ e e STA • • / \. \ ' •, ·��·�./��==�� COMBtNED ', .._----.... -- --- .... SEPARATE USPS EMSS USPS EMSS STATIONSl STATIl ONS Figure 2-4 . EMSS stations as part of EMSS system as an example of planning factors . 40 required between EMSS stations . That is purpose of this task area another proj ect area for the ITS . is to develop planning 2) Development of Service Planning factors for EMSS trunk Factors . Extensive definition and local communication of services to be provided to networks . Work has been the public by EMSS is u.s. started to investigate a taking place . The definition two-level hierarchy TDMA includes applications (e.g. , FDMA satellite network billings, general messages) , using the 4/6 GHz and media characteristics for 12/14 GHz bands . This input and output , speed of work will be achieved message delivery , customer through a tradeoff study access to EMSS facilities , to be developed in this message quality , enveloping , task that permits a quan cu tomer billing, EMSS pricing , � titative evaluation and pr1ces of services competitive choice of the four combi to the EMSS , and customer costs nations of mu ltiple access to use the EMSS . and frequency bands . c) The EMSS network planning support entails Remote Siting Assessment for the 4/6 GHz Bands . the following tasks . The purpose of this study 1) Computer Program and Data Base is to develop planning Adaptation . In this task the factors for the location ITS is undertaking a modifi and remote siting of EMSS cation of a contractor-deve l earth stations in the 4/6 oped network costing and GHZ frequency bands . A parametric analysis computer review is to be made of model for the EMSS , Implemen existing and planned tation will be on the Boulder terrestrial microwave Laboratories CDC 6600 . Involved are the update of the network locations , satellite costing data base as tariffs earth station locations , change for common carriers and frequencies , modulation , domestic satellites , update of and interference coordi nation distances for the equipment costs in the program same 75 cities as (a) file , adaptation of the network above , to determine costing model to calculate preferred frequency bands costs and channel miles for a for an EMSS satellite minimum distance network, network . fully interconnected networks , and modification of the computer model to reflect recent require Access Area Digital Swi tching System ments . (AADSS) . The U.S. Army Communications Systems Agency (USACSA) Monmouth , 2) Development of Local/Trunk at Ft . continued its sponsorship of ITS Network Planning Factors . �J , work on military local and access area This task is divided into the communications . Previously reported ITS technical areas described efforts have dealt with parametric below . distr ibution system studies for the near a l Attenuation Assessment of future . The substance of this background 12/14 GHz Bands . This study was reported earlier in OT Report work is near completion 76-95. with a report entitled "Earth-Satellite Links in In 1977 the program was extended to the U , S , A, '' by E , ,J , include Access Area Digital Switching , a Dutton . In this report task that has continued through FY 78 attenuation modeling Initially, and to some extent even no , predictions for earth � there appeared to be considerable uncer s�ace links are compared tainty about the criteria to be used in w1th data £rom the com assessing switching hubs for military munications Technology bases and access areas . various features Satellite (CTS ) and from ' so e service-oriented , some technically- radiometric measurements , � or1ented , and yet others identified as Then predictions are made performance critera, were described in a at 12 .2 and 14.5 GH z October , 1977 Special Report to the tor 75 possible U,S.A, sponsor , entitled "Preliminary Evaluation based earth stations Hub Alternatives for Access Area pointing to several Of Digital Switching ," The same Special potential geostationary Re�ort also r viewed currently available satellite locations . . � sw1tch1ng equ1pment , including stored bl TDMA-FDMA Tradeoff and program PABX 's, store-and-forward me ssage Hierarchy Satellite and packet switches , as well as real Network Study . The time message switching systems . The 41 review paid particular attention to CCITT 's X.25 (or its equivalent , SNAP ) seven implementation alternatives based have been considered and assessed in on PABX technology . The more promising light of AADSS unique requirements . options were singled out for later scrutiny . AM Stereophonic Broadcasting . on July 6, 1977 , the Federal Communications Division NTIA Report 78-2 , "Access Area Switching released a Noticy of Inquiry (No . 9) and Signaling : Concepts , Issues , and regarding AM sterophonic broadcasting as Alternatives " reflects two topics of a result of two petitions requesting wo rk . First , it describes and analyzes adoption of rules to permit stereophonic an attractive example of a stored broadcasting by AM broadcast stations . program-controlled digital switch . Endowed with interchangeable , analog/ Eventually , five competitive systems digital , line/trunk cards , as well as were proposed, respectively by Belar , with remotable concentration modules , Harris, Kahn , Magnavox , and Motorola . the prototype switch shows many advantages The ITS study focused on aspects which for the future access area . were not thought likely to be adequately treated by others , i.e. , the sponsors of The second half of Report 78-2 deals the various systems or the National AM with signaling functions and methods Stereophonic Radio Committee (NAMSRC) . that are currently in common use for the remote control of circuit switches . In particular , ITS conducted analysis of Figure 2-5 shows some of the interoffice spectral occupancy , effect on coverage signaling concepts . Part (a) depicts range (both monophonic and stereophonic ), conventional associated signaling , where and distortion as a result of restricted individual signaling units are assigned receiver pre-detection bandwidth and as to individual trunks . Part (b) illus a result of the effects of skywave and trates a more recent , and more economical ground wave interference (fading) under development , called common-channel nighttime propagation conditions . associated signaling . Here a signaling Spectral occupancy is of importance as line parallels a group of trunks . All it influences the possibility of achiev signaling lines end in one or two ing maximum spectrum utilization of the signaling terminals , thus reducing available broadcast band . Adoption of signaling hardware and cost. Part (c) stereophonic h� broadcasting would of Figure 2-5 shows the nonassociated stimu late the production of M1 receivers version of common channel interoffice with synthesized tuning and more widespread signaling (CCIS) , This final version inclusion of , for example , adj acent appears to be the signaling system of channel whistle suppression filters , the future for North American telephony , which would de facto preclude any future change of channel spacing . Coverage With the advent of integrated data/voice range (i .e. , monophonic and stereophonic systems , control signaling and network S/N ratios as compared to straight management involves a complex interplay monophonic transmission) and distortion between all the network elements (termi resulting from restricted receiver pre nals , links , mode switches, and separate detection bandwidths are , of course, of autonomous subnetworks ), New advanced importance in providing the best consumer signaling techniques and mu lti-level service and are also of major importance protocols are being developed to exercise to the broadcaster . Finally , perfor- automatic remote control of processes mance under conditions of nighttime that in turn control the traffic flows . propagation is of importance to many New service features and system functions rural listeners who after sundown may be involve large commitments in software fully dependent on skywave reception . and associated hardware development . The results of the ITS studies were sub ITS work during the summer of 1978 was mitted to the FCC in Initial Comments on concerned with such advanced signaling Docket No . 21313 in January 1978, and in aspects . Figure 2-6 illustrates the further Reply Comments in March 1978. more significant AADSS system interfaces . At the time of writing , a decision had These interfaces have a variety of no t yet been taken by the FCC . transparency requirements for control signaling in the foreseen , 1980-1990, MARAD Assistance. Since 1973 , ITS has analog-to-digital transition period . prov�ded a range of technical services to the U,S, Maritime Administration This ITS work on advanced signaling is (MARADl , including test facilities and summarized in a draft report, "Control as sistance , technical representation in Signaling in the Military Switching connection with advanced communications Environment ." As of August 1978, the proj ects , communication systems studies , draft was still in review . It is sched and inputs to the CCIR. Some of the uled to be available in October , 1978. specific efforts in FY78 are described Various data communication protocols , in Lhe ;f;ollowing paragraphs . such as the bit oriented SDLC , the byte ll ITS provided the technical oriented DDCMP , the character oriented input , and was the u.s. Spokesman , BISYNC , plus such packet protocols as at the CCIR Study Group (Mobile 42 Signaling Equipment Trunks �-' �� - -x1 - - fx - (a) Con ventional Associated Signals Trunks (b) Common Channel Associated Signaling Signaling Network ( c l Common Channel Nonassociated Signaling 2-5. Figure Interoffice signaling concepts . 43 ""' ""' TACTICAL NETWORKS ( TRI-TAC ) 2-6. Figure Main interfaces in the access area. Services ) Final Meeting in January by identifying and consolidating public 1978 on Digital Selective Calling service sector needs . (SELCALL) and Direct Printing for the mob ile maritime services . The objecti�es for FY 78 were : These efforts culminated in the revised Recommendations 493-1 a. through studies and participation '(SELCALL) and 476-2 (Direct Printing ) in WARC 79 preparations concerning which were approved by the XIVth future needs and uses of the 12 GHz Plenary Assembly of the CCIR in frequency allocation , assist in the June 1978 . In addition , ITS provided resolution of regulatory , technical, technical consulting to several and economic barriers to the use of manufacturers relating to Recommen small earth stations in cooperation dation 476-2 . with NASA , other Fede.cal agencies , and U.S. industry ; 2) ITS , as technical representative b. monitor the progress of NASA , PSSC , for MarAd , par�icipates in the work and other agencies in developing of the Radio Technical Commission public service sector satellite for Marine Service (RTCM) , Subcom communication requirements to mittee for Automated VHF Maritime determine the possible need for a Mobile Telephone Systems (SC-71) pilot program of high-powered and has been a U.S. member to the direct satellite communication CCIR Interim Working Party 8/5 on systems with associated small earth the same subject . Some of the stations ; and results of the work accomplished c. complete the analysis of technical during FY78 is published in NTIA barriers limiting the earth station Technical Report 78-4, "Interfacing antenna size requirements in the the Automated Maritime Mobile interference-free situation . Telephone System with the u.s. Public Switched Telephone Network'' . A study was conducted which addressed This report details the unique some of the past, current, and planned difficulties in the u.s. marine activities relating to the U.S. domestic communications field , such as the satellite communications services , both heterogeneous makeup of communi fixed-satellite services and broadcast cations ' providers (i.e. , telephone ing-satellite services. Since there is company owned and independent coast not yet a domestic U.S. broadcasting stations ), regulatory restrictions , satellite service , the primary emphasis insufficient spectrum resources , was on the fixed-satellite service. The and economic considerations . r t results of this study are reported in further discusses some of the NTIA Report 78-9 . characteristics of the U,S, tele phone network as it affects the The development of the u.s. domestic automation of maritime mobile satellite common-carrier systems was public correspondence services and traced and the current status was pre presents concepts for interfac ing sented . The general technical character the radio portion of such services istics of the current-generation communi with the public telephone network . cation satellites were included . SECTION 2.2. SATELLITE COMMUNICATIONS The technical design of these satellite communication systems requires the use The main effort in the satellite communi of relatively large earth station anten cations program area during FY 78 has nas . Typical minimum earth station been on the direct funded project which antenna diameter for transmitting is in was initiated in FY 77. On this project, the range of 10 to 15 meters . While for the regulatory , economic , and technologi a receive-only TV application , the earth cal barriers to the development of small station antenna diameter is typically antenna earth-station systems have been 4,5 to 10 meters , depending on geograph studied. work has continued at a low ical location and the required TV pic level on satellite communication related ture quality , work sponsored by other Federal Agencies . For example, the GOES ground terminal An important aspect in considering the Equipment Certification has continued . potential for growth of small antenna earth-station systems is the regulatory Direct Satellite Communications , The and frequency allocation climate in long-term objective of the Direct Satel which such systems can develop . The lite Communications project is to con frequency band having the greatest tribute toward the goal of increasing potential for accommodating small-antenna the likelihood of satisfactory systems earth- station systems is the 12/14 GHz performance as affected by natural , band . However , if thi s band develops engineering , and economic factors and to Ca s it appears to be developing) in the accelerate the use of direct communi same manner as the 4/6 GHz band has cation satellites by lowering barriers developed , the small-antenna , earth to the use of small earth stations and s tation system development will be 45 foreclosed in the 12/14 GHz band also . of its sharing by a number of users mu st The future growth potential for satel be assumed and the effects on the mini lite conununication systems is one of the mum antenna dimens ion determined . very important problems that needs serious consideration during preparation In order that more direct users can be for the 1979 WARC . accommodated in satellite conununications , it is essential that one can estimate Some tariff information on the cost of costs associated with both earth station private-line service offered by terres and satellites for various services . tr ial and satellite conunon carriers was The results of this study are expected studied . The capital equipment invest to be useful for such cost estimation . ment requirements for satellite com mun ications is not dependent on the Preparation in the United States for the distance between the earth locations 1979 General Wo rld Administrative Radio being served . However, the tariff rates Conference (1979 GWARC ) has been in on file with the FCC are distance progress since early 1975. These prepar dependent. This distance-dependence of ations are being conducted by two entities : the tariff rates appears to be based on (1) the Interdepartment Radio Advisory a competitive pricing strategy , rather Committee (IRAC ) Ad Hoc Committee 144 than on the cost of providing the service . for the Government sector and (2) the Federal Communications Conunission (FCC) , The study for determining minimum dimen by internal planning and solicitation of sions of earth-station antennas , carried public comment through the not.ice-of over from FY 77, wa s completed for inquiry , for the non-Government sector . various cases of single carrier per The ITS studied some technical and transponder . The results of this study economic aspects related to the fixed were reported in OT Report 78-145. satellite and broadcasting-satellite services operating in the frequency Covered in this study are FM TV , FDM"·FM ·range from 2.5 GHz to 14.5 GHz . These telephony , multiplexed PCM-PSK telephony , services operate in portions of this and PSK digital-data transmission . Any segment of the spectrum designated for other type of signal can be added without non-Government use in the United States . difficulty if the need exists for the signal . This study focused on the technical and economic issues associated with spectrum Although we have tried to determine and orbit-use planning for broadcasting actual values of minimum antenna dia satellite and fixed-satellite services meters for given types of signals , we in the 2.5 to 2.69 GHz frequency band have not been able to eliminate all and in the frequency bands between 11 .7 uncertainties in this study . For the to 14 .5 GHz . The key questions addressed reception of a TV signal , we have are : determined a range of values for the minimum antenna diameter . For telephony o How should flexibility for the 1982 signals and digital-data signals , we Broadcasting-Satellite Regional have calculated sample values that Administrative Radio Conference correspond to assumed sizes of the (RARC ) for Region 2 be developed system and assumed values of the satel and taken into account in planning lite EIRP , If more specific values of for the 1979 GWARC ? these system parameters are known , we can narrow the uncertainties . o What new spectrum resources should be planned for the broadcasting Actual values of minimum antenna diameter satellite and fixed-satellite are of the order of l m for the recep services in the 11 .7 to 14 .5 GHz tion of FM-TV broadcasts in most places bands? in the contiguous 48 states of the United states , if the broadcasts are o How can small earth terminals be done in the 12-GHz band in accordance accommodated? with the 1977 WARC decision . For multi plexed telephony carrying 60 telephone o How can hybrid satellites introduce channels or less, the minimum antenna greater flexibility in planning for diameter is about 5 m or less , if the the 1979 GWARC and 1982 RARC? satellite EIRP 's of 30 dBW and 40 dBW are available for the 4-GHz and 12-GHz o Why do orbit-division and spectrum bands , respectively . The same is true division policies developed in for digital-data-signal transmission of preparation for the 1977 WARC-BS 3 Mb/s or less. Except for the FM-TV need reexamination prior to the case , however , the RF bandwidth is only 1979 GWARC ? a small fraction of the nominal 36-MHz or 40-MH z bandwidth of commercial o What planning could be done to en satellite transponqers. If a currently courage utilization of the 2.5 to available commercial-satellite trans 2.69 GHz band? ponder is to be used , effective methods 46 o How can high EIRP (ef fective iso ·top computer sys tem which will permit tropic radiated power ), multiple the line-of-sight microwave system beam satellites be accommodated engineer to evaluate many design con below 15 GHz? figurations with immediate feedback in terms of system performance and cost These and other questions were reviewed , trade-offs . The concept �f this engi and recommendations for planning were neering model is based in a large part given to the extent possible. on the information and methodology contained in MIL-HDBK-416 , which was The results of this study were submitted prepared by ITS under an Air Force to the FCC in an informal report and contract . The handbook was written will be published as an NTIA Special several years ago ; consequently , empha Report . sis was placed on analog systems (FM/FDM ) with little information on digital Proposed changes of the ITU Table of systems . With the passage of time , many Frequency Allocations , based on the of the original models used to predict above comments , were submitted to the path-loss var iability and other factors IRAC Ad Hoc Committee 144-I for consider affecting performance have been improved . ation for inclusion in the u.s. proposals Much emphasis on this program (spon for the 1979 GWARC . sored by USACC EED-PED) is placed on adding needed models and updating ones Late in FY 77 a contract was negotiated which have been improved . with TransCommunications Corporation , Greenwich, Connecticut , for a study on Seven programs have been developed . the current status of the domestic satel These programs make key calculations in lite communications industry . This study the design of line-of-sight microwave includes development of an information systems . The mode ls have the following data base on domestic satellite , earth ranges : bit rates up to 50 Mbits/sec , terminal systems . This data base includes carrier frequencies from 1 to 40 GHz , a listing of earth terminals , equipment and path distances up to 150 km . The technical characteristics , type of use programs calculate , tabulate , and plot application , and their interface to ter information about earth geometry , path restrial systems . The contractor final profiles and ray paths , median basic report wa s completed this fiscal year . transmission loss , path-loss variability , equipment gain , link performance , and Certification of GOES Data Collection system performance . Models were chosen Platform Radios . The GOES satellites are based on their wideness of acceptance in earth-synchronous orbit for the pur and the size and type of data base pose of monitoring the earth environ substantiating the model . In order that ment. A part of the monitoring is accom the design engineer might have immediate plished by relaying information from access to the calculated results of remote data collection platforms on the changing various design parameters , the earth . programs are written for use in an interactive mode by people with no The ITS has an on-going program for certi experience in programming . fication of the data collection platform radios . During FY 78, performance tests An examp le of one of the outputs of by three manufacturers were witnessed by Program No . 2 (Path Profiles and Ray the ITS certification officer . Results Paths ) is shown in Figure 2-7 . of the te sts were submitted to NOAA/NESS . EFAS/PEP II Program . This program SECTION 2.3 . TERRESTRIAL RADIO addresses the technical performance SXSTEM PERFORMANCE characteristics of the Digital European Backbone (DEB) communication system This activity is directed toward the de shown in Figure 2-8 . The DEB program is sign , ev aluation , acceptance, operation , directed at the conversion of wideband and upgrade of existing or proposed sys analog systems to secure digital tele tems operated by the Federal Government . communication systems . As a portion of The proj ects generally result in recom the change-over and upgrade , many links mendations for system design and/or up are being reengineered . Of particular grading as requested by the other Federal concern is a 160 km link that is being agencies . Five tasks are reported , changed to operate at 8 GH z. A portion namely : Automated Digital Systems Engi of this program was to collect the path neering Model , EFAS/PEP II Program, Air variability data to substantiate the craft Interference Effects , Lightning engineering predictions . Protection Evaluation of Spanish Terri torial Command Network {_T CN ) , and Non Data were collected during the period tactical Radio Networks . between October 19.77 and January 1978 . The European fall is. punctuated with · Automated Digital System Engineering extensive stationary high pressure zones Model . The purpose of this proj ect is that cause stable stratification of the to develop programs to be used in a desk atmosphere and thus encourage excessive 47 DISTANCE Cmiles) 0. 00 12.43 24. 86 37. 29 49. 72 62. 15 1000 3280 � lc;titude long i tudo Elevation (rn) � �·- -·- · k"" 4/3 ---- LKF 49 18'04"N 7 50 '47"E 602. 0 k o 4/3 FEL 50 14'33"N 8 29' 49"E 688. 8 ---- 900 k· 4/3 2952 Path length "" 114. 55 krn k"' 2/3 25 Ap�""il 78 Project No. 9103504 ORW 0. 60 Frounu 1 Zorro 800 at 8. 32 GHz 2624 700 2296 00 · L 600 " 1968 � m +> +> " (!) m m E ·"- / 4- � 500 !/ 1640 � � " / _j . ·"- / _j (f) (f) ::<: ..'- / ::<: 400 � 1312 .,. "'- w w 00 / / .. > '\ • I > 0 !\ 0 I. . ' \ CD � CD 300 \,I / < r\ � 1 984 < "· A ' ·� z \ z 0 J ) 0 t � I- 200 J 656 I- < < > �� \ > w w _j ' _j w 100 J 328 w 20 \J\/40 /60 80 100 120 DISTANCE (k ilometers) Link Profile from FELDBERG to LANGERKOPF Figure 2-7 . Profile plot and ray trace. GERMA NY AUSTRIA ...... _ .,.--...... �, Cima Gallina '}"' -� \ _ ...... __...... ----..... � ITALY Adriatic Sea Mt. Cimone Mediterranean Sea Figure 2-8. Digital European Backbone System , Phase I. 49 I I I I jiillilI " II I I I I ( ( I I I I"" )'"' J ' ' - f -4933 Lower Ant. -SB ...... E a:::a -o...... -( -69 Q) > (I) __, ....-( 0 &r78 (f)..... -oQ) > ...... Q) � 0::: -BlJ I , I I LJ I I fillI I I I I 1, II 10 53 91J 99 99. 9� 99.99 99. 999 Percent of Time Level is Exceeded ZUG - HST R. S. L. 14 Oct. 1977 - 20 Oct. 1977 Figure 2-9. Received signal level distribution for 160 km link . 50 t·lo Equi PMent Site t:i n:=. l.. .!s · �� Major Minor Maj or Minor ParaMet�r * ·�· 1·,·' Hl··i \:1 o. J. h ln··�E·n H n d 0 ::: ·r f-k• f·� ·� :::. '='- t ** ZUG zugsp i,.ze ** CIM riMa Gallina *� PAG p� gane .. la ** t·1 CA l'h C·:· !TIO. ** tHC t·1 t C i i"'Oi·"; E· "·* t·1 ::; ri nt ::; .;;· ·- t·o. -:t--t· CLC' Colt o. no · t·i TE 1·1t. \l �·; ;d•J. *·�� 1•/ Ch \·1 i c .::·nz(i. ** CEC C�.. ;t ·;;;i o. ** A \·1 0 AI..J i 1J. n1:1 ** FZM Friolzh eiM Ent. •:· r COf';f';o.nd : HST - Hohenst.adt S i i. E· -M I NOP- D:srouP HST-2: CL0-2 212. i21-i .?2 -STATUS-Towe r Lisht Disable 2 i :::: .· Ci ·'i·Z�2 -STATUS-R�ct ifier Sha rins Load �? 1 -·· ��1 :::1. 22 - :;:;r t'l T u ::>-· " o. n :;. i on . 04��2 E : : r-:· : 1 . - ::; T : T E· t. 2L:� �:: T i.J: ; --F H 3 s. 21 ::� (1 ·!:22 -STATUS-Gene rat or NuMber On 21::: D·L� 2 -STATUS-Towe r Lisht On 21 ;2. '(lq;:� ;::: -STATUS-Fuel PUMP NuMber 2 On 2 l 2 ··o.j. .2.� M0175. 1-ZUG-M I NOR- StandbY Mux Fault 212 ('1 42:2 -STATUS-Receiver A Se l ect 212•04� :�-� .. . -STATUS-T ransceiver 8 Disab le 212. . 042:�: t·l0 �i5 ·::> .2-'·/ HtH'1I IIOP- E: HIT Fo.i lur.:· -M I NOP- ExPans ion 212·'0422 9 . e 212.. .. 0�+��:2 .: =:�:i�n::�:=��:�:�:�:;:�: �- .....e ;: � i, � �:�. b 1" 212./(i :l .?.:�� Figure 2-10. Sample enhanced fault alarm system displays . 51 microwave multipath fading . The effects 15 - 20 MHz passband of a microwave of thi s phenomenon are illustrated in digital receiver . Stated another way , Figure 2-9 , detailing the distribution of the received spectrum contains some the received signal level . slope in response that could potentially cause distortion in the received data . Another effort undertaken with the new Little has been done however to correlate communication sys tem is the inclusion of this phenomena with system performance . an extensive alarm and status remoting system. ITS is preparing a multi Lightning Protection Evaluation of minicomputer system that is intended to Spanish Territorial Command Network (TCN) . control and po ll the remote sites to This project had as its objective the preser.t system conditions in a form most analysis of sp ecific problem areas impact useful to the operator as well as to ing the performance of the Spanish Terri record all system changes for later torial Command Network (TCN ) • analysis. Two of the displays to be used in the system are shown in Figure The Territorial Command Network (TCN ) is 2-10. a complex network which utilizes line-of sight , diffraction , and tropospheric Another task to be undertaken is the scatter microwave radio links to provide collection of information from other voice, teletype , and high-speed data com parameter s not associated with the alarm munications between Army and Navy instal system . Among these will be detailed lations throughout the mainland of Spain received signal-level data , power system and the islands of Mallorca and Menorca. reliability , and subscriber channel block The specific problem areas to be inve sti error rate and ava ilability . gated by ITS related to the adequacy of protection against lightning strikes , Aircraft Interference Effects . Conver various electrical transients , and longer sion to digital transmission has renewed term power fluctuations . the concerns about what effects aircraft obstruction of microwave links have on After a review of the TCN specifications user quality . This is of particular CU , s, Army Communications Electronics concern where it is necessary to install Engineering Installation Agency , SCCC- a telecommunication system that crosses 73003) , it was necessary for ITS to mea runways and taxiways where the frequency sure the ground resistance of several of obstruction may be great. selected sites , to inspect several sites for conformance to the specification , and A limited measurement program was under to measure power fluctuations . taken to determine if a condition existed that could cause excessive error rates There are 40 fixed sites in the TCN , with on digital systems . Measurements were most of the sites being in the categories made at Atlanta and Chicago International of tactical, terminal , active repeater , Airports where 8 GHz links that crossed and passive repeater . Tactical sites are runways were already established . located on mountain tops and have a high Received signal level measurements were vulnerability to lightning strikes , made along with monitoring baseband lightning induced transients , and signifi noise on the oper ating system . A paral cant voltage fluctuations since they are lel measurement was made using ITS at the end of the commercial power developed equipment to determine the distr ibution system , continuous im.pulse response of the transmission medium. A group of 6 TCN sites were selected for detailed study after consultation with Measurement results indicate that, during the TCN Deputy Project Manager in Spain . takeoff and landing , aircraft can be the Each of the selected sites was visited cause of signal level fades to 20 dB , but and a measurement taken of the ground the baseband noise did not increase resistance of the site grounding system significantly . r1odern system margin is and , where practical, a tyPical measure sufficient to cope with such fades . A ment of earth resistivity for each site typical fade is shown in Figure 2�11 was taken . Discussions were held with and an obstructing aircraft in Figure site personnel regarding lightning- or 2-12 , In Figure 2-12 , the transmitting transient-induced equipment failures . antenna is identified by the arrow . Observations were made concerning air terminal (lightning rod) installation , The impulse response measurements at down conductor (B"rounding conductor) type , Atlanta did not reveal any delayed and routing, and whether or not these J?Ulses that 'I'Ould indicate excessive conformed to good engineering practice multipath nor any pulse distortion which as well as the specific codes covering would imJ?lY frequency-selective fading . these types of installat ions . Record However , slight dis tortion from taxiing ings were taken at each site of the aircraft at Chicago was observed . The 220/380 3 -phase power for periods of 1 to implication of this detected distortion 3 days . These recordings were taken with is reflected in the possibility of a a commercial power-line disturbance distorted frequency response within the 52 ·. ••. =����=,1 ,· , ...1, • •••• d '.. ,,, . ffiUrtn� .. ITD�' . . • .; • • 'Iii11 , _, , • .. t •. :i:+l� . . *• t+-tr+ •. l�i• t.slL'+:ht 1 r . •• :::� w;:+ I ! ! I ' 'i ::' 1H J · 1J ,-t·.' ' .·.···A ·: �� U1 1 lei• JC' 1 �I;'• '! w . ! ·. .• .,., · ' ·- 'J I , ' ,., • JW "j. 1 _ • , ·• - J. _ .! ;;;.h ladI ,, , •t 11, 1 J -;!-i ·c·; -· TI:i · •F/:': ' '' , : , .L � I ]'1: ;iJll!0:!r:.:3 _ • '• ,! •:; f .. · sl •: I ' .• : ... , •Cf ' '�. '"lct •' · ·•;c ;; : '• ''+ · · j_+·· --: ' Ht I' I . ·i ; i"t i' iT ; ,;.1 � T" _,+.i.� ; f:ill\f j] ·' ' : rrr" i',-; • r :t _ _,.,, . 'L i ] ! ' , . - ""... . ' ,, ,, ;; ' \'1/C\i.ll !• i•'·, '·•••··Tic ��; Th, .• + ! T L {:..,.: ''rt i� ' "'' •·'tilil !;��· -ij, )' I ;-· " i \',"" ,, T:,, JJI �.�, ' ' •. ... . ·'·IF· '" o7f ' . -'- -i·I.i.!..:.t ! . �·_ tt+ :'i[::- J: I . ·'·- -1---,--' .' �' . . I 1- '' , J"lV . l . I.. .. s.�1:�::� : . �::,.�% ��.t�r-.1 f,.. - + I , ··::: •m; '·' , ·' "" . : :1f 111 � iiT·:�: ·:. �·· I lit'*�4sde;,,' " ' : :· : ' ,' 'l:.f: '" ''" ,.,. ',, ''" ....� : ''\,: ;, IC b :]i����:hl'+Fii-q ,, , • l'!i ''d:{ •. •.. if9 r . , , , , , ' Lbil , +'· I I1 "'"· , 1 , ''";··+' ill"' .. R I ���� :m::.Jn:m.::r:r.'�· :: ::· , ·:. : ., : :::;r:., ii I' , ,,,. " t"B. j.. . e. c . eli ." ""' J I ·-'---- I Figure 2-11. Sample fade caused by aircraft. N ,...; I N 54 analyzer that recorded slow average volt and operating and maintenance personnel . age (10 second moving average ), Sag/Surge The obj ective of these interviews was to (transients having a duration from 1 cycle collect data in the following areas : to 10 seconds ), impulses (spikes having 1. Configuration of the network a duration between 0.5 and 800 micro 2. Equipment used seconds) , and frequency variations (mea 3. Operational procedures and sured over a 1 second sampling period) . requirements 4. Service objective and scope A report was submitted detailing the mea 5. Coverage required and exper- surements taken, the conclusions reached , ienced and the recommendations made for improv 6. Internet requirements ing the system reliability . 7. Grade of servlce 8 . Maintenance procedures . Non-tactical Radio Survey . The United States Army , as well as other branches The responses and data collected in of the military services , uses �on these interviews have been compiled into tactical radios for a great variety of a final report for the project sponsor . communication services on their posts The results will be used in developing and bases . These uses range from the plans and techniques for new integrated networks common to each post that serve communication networks on Army posts in the security and military police systems the future . To further assist in this to the highly specialized need to endeavor , the project also included a communicate from the floor to an overhead survey of the non-tactical radio equip crane operator in a large assembly ment commercially available today and in facility and the control necessary on a the near future . gunnery range . SECTION 2.4. SIMULATION AND STANDARDS The radio networks vary significantly in size and complexity . Most of the systems Simulation and standards (including hand operate in the VHF frequency range , books and glossaries) are combined in this using FM (16F3) voice modulation . A few program element . Simulation provides a operate in the UHF band , however , generally realistic and repeatable method for eval for applications where the higher uating and comparing the performance of frequencies provide improved perfor- different subsystem elements (e.g. modems ) mance . on an obj ective basis . Three tasks are described ; namely : MEECN Simulation , As a result of an earlier study performed Radio System Glossary Update , -and Et1S by a special committee , the u.s. Army Technical Planning Guide . Communications Command (ACOM ) at Fort Huachuca, �z , planned for an in-depth MEECN Simulation . The objectives of th is survey of the applications , service project are : concepts , and procurement procedures ll To perform synchronization tests on used by the Army in this non-tactical the u.s. Air Force 616A and U.S. Navy communications field. The Institute for Verdin VLF-LF digital radio communi Telecommunication Sciences (ITS ) con cation systems . ducted this survey under the guidance 2) To develop and evaluate an experimental and sponsorship of the Army . In order adaptive filter that can be used in to provide a good statistical sample digital spread-spectrum receivers to that would be representative of the suppress interference (unwanted sig entire Army , a total of eight instal nals) . lations in the u.s. were selected for the survey . Two locations in each of The 616A and Verdin are sophisticated sys the following classifications were tems that incorporate several modulation selected : techniques with a number of compatible modes of operation that are used in the 1. Headquarters Minimum Essential Emergency Communication 2. Training Bases Network (MEECN ) of the Department of Depots 3. Defense . Near the end of FY 77, labora 4. Proving Grounds . tory tests were performed on the 616A and Verdin systems under ideal channel con A team of two ITS engineers visited each ditions to determine the intra-system and of these installations . The local ACOM inter-system synchronization character detachment served as hosts and coordi istics . The results of the synchroniza nators for the visiting team . Interview tion tests are described in a classified sessions were scheduled and conducted report that was prepared dur ing the first with cognizant personnel for each network quarter of FY 78 (Watterson , C.C. , 616A operating at the particular base . The and Verdin Back-to-Back Compatibility latter were identified by the local ACOM Tests , Sets 1-3 (U) , OT Tech . Memo . 78- staff, and from frequency assignment 246C , January 1�78, pp . 1-75 (Secret) records furnished by the Army . These Dept . of Commerce, Boulder , CO survey interviews were conducted with u.s. 803031 . those in a management role , individual users, dispatchers (where appropriate), 55 The design and construction of an experi receiving-system performance provided by mental adaptive filter for the suppres the adaptive filter with CW and FSK sion of unwanted-signal interference in interference . The tests confirmed expec spread-spectrum receivers was under tations that dynamic nonlinear operation taken and completed two years ago , in FY of the adaptive filter can provide 76. Laboratory experiments on the adapt greater improvement than quasi-static ive filter , planned for FY 77, were post linear operation . A classified NTIA poned because of other project commi t Report entitled , "An Adaptive Receiver ments . During the last three quarters of Filter for Interference Suppress ion in FY 78, the experimental work with the Digital Spread-Spectrum Radio Systems " (U) adaptive filter was resumed and essen is being prepared on the design and char tially completed . acteristics of the adaptive filter and the improvement observed in the 616A The performance of any digital receiving receiver performance . The report will system with respect to interference can be printed early in FY 79. generally be improved by incorporating a suitable filter that automatically adapts FED�STD�l037, Vocabulary on Telecommuni or adj usts its response, according to the cations , This is the first Federal characteristics of the interference, to Standard to provide a mutually agreed increase the signal-to-interference ratio . upon telecommunication vocabulary for Adaptive filters can be particularly use by both the DoD and non-military ef fective in spread- spectrum receivers, Federal communities . The terms and where the performance improvement they definitions in this standard are compat provide is an addition to , and in some ible with usage in Federal systems cases much greater than , the usual chip performance standards currently under processing gain . The improvement in review and will form the nucleus of a receiver performance that an adaptive commonly unders tood language for future filter can provide depends on the ratio standards within the FED-STD-1000 series . of the bandwidth of the modulation on the This standard is also to be adopted by interference to the bandwidth of the the DoD to replace MIL-STD-188-120, spread-spectrum signal . With CW inter Military Communication Standard : Terms ference, the bandwidth ratio is zero , and and Definitions , which formed the initial the improvement is ideally infinite . For data base for this FED-STD . Thus , other types of interference , the improve FED-sTD-1037 will also provide the ment decreases as the bandwidth ratio definitive language for subsequent increases , with relatively little or no revisions of and additions to the improvement remaining when the bandwidth MIL-STD-188 series of systems perfor ratio approaches one . To obtain the best mance standards . Continuous updating of performance, a practical adaptive filter the glossary is anticipated in order to must utilize digital processing . For keep abreast of new technology develop small bandwidth radios , the improvement ments and applications. This reference in receiver performance is consequently list of terms and definitions will not limited by quantizing noise . It was shown only provide a common terminology for that the theoretical improvement in the writin� and interpreting commun ications signal-to- interference power ratio in a standards, specifications , and contracts , digital spread-spectrum receiver with CW but will also aid in designing , develop interference when limited by quantizing ing , operating , and maintaining of oper noise ;Ls a. tional systems . This work ha.s been funded by the National Communications system {_NCS ) I coordinated where b is the number of bits/sample in v;La the Standa.r ds Branch of the U.S. the analog-to-digital conversion , ' is Army Commun;Lcat;i::ons-Electronics Engineer c the reciprocal of the chip rate , and f ;Ln<;J Installation Agency (USACC/CEE1A) • s is the sampling rate . The equation is Utilizing the computer-stored text of illustrated in Figure 2-13 . J11L.,.STD.,..l88-120 as the initial data base , ITS has employed an existing word-proces The experimental adaptive filter was based sing(text-editing computer software pro on a relatively simple delay-line model. gram to add more than 700 new terms and Basically , it is a filter which is auto definitions to the initial 1300-term matically tuned to maximize the signal-to data base, These new entries represent interference ratio at its output . During inputs from the non-DoD Federal Govern FY 78, comprehensive bench tests were per ment 1 coordina.ted through the NCS . The formed on the adaptive filter under simu resultant enlarged draft was distributed , lated-signal and interference conditions in early 1!178, to 75 reviewers, within to determine the optimum values of a DoD and non�:mi1itary Federal Agencies , number of adjustable parameters . Follow ;or critical comment , All reviewer com ing the completion of the bench measure ments were considered and resolved during ments, the adaptive filter was incorpor two 2 -week resolution committee meetings ated in the 616A receiving system , and a of a Federal Telecommunications standards set of channel-simu lator experiments were Comm;Lttee (}'TSCt subcommittee , in which made to determine the improvement in ITS was a particiJ?ant, in July and August, 56 I� - c Cl) E Cl) > 0 '- 0.. E 1-1 Cl) (.) c 0 '-E 0 '+- " Q) Q_ 5 10 20 50 100 200 Relative Sampling Frequency, Tc f5 Figure 2-13. Theoretical improvement in digital spread- spectrum receiver performance provided by adaptive filter with CW interference. 57 1978 . ITS is currently correcting the SECTION 2.5. FIBER OPTIC COMMUNICATIONS computer-stored draft to reflect these extensive modi fications , and will have ITS has had an active role in the rapidly photocomposed text ready for publication growing field of fiber optics communica in early FY 79. tions . This role has included such activities as publishing a fiber optics Technical Planning Guide for Emergency handbook , organizing and chairing an Ad Medical Services (EMS) . The Emergency Hoc Optical Communications Task Force , Medical Services Act of 1973 (Amended providing consulting services in fiber 1976) has made provisions for the estab optics to the Department of Defense, lishment of emergency medical service developing a data base for an optical systems in some 300 regions of the u.s. communications glossary , and sending a The concept is to provide border-to Chief U.S. Delegate to the International border emergency medical services to Electrotechnical Commission Subcommittee reduce morbidity and trauma for all on Fiber Optics. These activities are citizens . These systems cooperate with discussed in detail below . the National Highway Safety Act (1966) provisions which were designed to provide Optical Communications Task Force . In similar services for highway accidents. Fiscal Year 1975, an Ad Hoc Optical Communications Task Force (OCTF ) was A simple, practical communications planning formed . The creation of the Task Force guide has been prepared at the request of was inspired by the OT mission to "assist the Interagency EMS Comm unications working the Department of Commerce in fostering , Group , Chaired by NTIA . The guide is serving , and promoting the nation 's intended to provide the basic information economic development and technological needed by a non-technical planner (.e.g. advancement by improving man 's comprehen hospital administrator or registered nurse) sion of telecommunication science and by who has responsibility as part of a re assuring effective use and growth of the gional EMS council or committee for plan nation 's telecommunication resources ." ning, procuring and evaluating appropriate The Task Force work is carried on today communication equipment and facilities to under NTIA 's mission of serving as a support a regional EMS system. national focus for Federal policy and decision-making in those areas vital to The guide has been prepared from materials the new Age of Information . recommended by the DHEW EMS Regional Con sultant Team and from recommendations ITS has assumed a role as a catalyst in received at the three DHEW Tri-regional assisting other Government agencies to Workshops of 1977. Guidance was also more rapidly develop and apply advancing given by the Interagency Working Group . communication technologies such as the emerging fiber optics communication For the purposes of this guide , the func technology . The OCTF was developed to tion of the communications system are provide a forum for government and citizen access, dispatch and medical industry technical workers, potential supervision during patient care and sta users , and policy makers to explore the bilization at the scene (providing medical applications , advantages ,and potential supervision for paramedic personnel) , and problems in adopting and using optical continued medical supervision during trans communication technologies . port and delivery of patients to an emer gency receiving room at an appropriate The Task Force work has been well received hospital. A diagram showing the communi with the meetings well attended by cation system is shown in Figure 2-14 . representatives from industry , univer sities , and government. Frequently , the The guide stresses the need for defining Task Force participants have benefited the EMS system and the required communi from the introduction of topics earlier cation paths and surveying , understanding than they would have been introduced in and securing cooperation from related a formal societal meeting . One such public safety communication resources topic introduced in this year 's meeting (_e.g. police , fire , civil defense. , .) of of the Applications and User 's Working the region prior to the design and pro Group was the topic of using fiber curement of an EMS communication system. optics communications in the hospital The rudiments of system planning , procure environment . Medical care costs in the ment , and evaluation are presented . Alter U.S. exceed $180 Billion annually , and native system approaches are discussed . hospital costs are about 40% of this The guide is not intended to replace the total . Cost effectiveness to promote consulting services needed for system quality health care in hospitals is planning , but is intended to make the in understandably a large concern . The terface between planner , consultants and wide variety of communications , data suppliers (manufacturers) more effective . processing , and wideband telemetry needs in a hospital makes it an important arena for the introduction of broadband communication services. Fiber optical 58 C ITIZEN DI SPATC H a C OORDI AMBULANCE NATE w z T-467 ....J. w +I R-462 z 0 ___ _ I @L-- T-463 a... R-468 DISPATCH or COORDINATION 1--_.J CENTER I T- 4'62 I R-467 __ __ U1 Doc 1..0 r0R w z i\ _J '- ----, \ w z 0 I a... HOSPITAL STAT ION T- 458 R-463 MEDICAL SUITCASE Figure 2-14. Emergency medical services communications. cables could be quite beneficial in are increased from A ; 0.85�m to A ; 1.2 providing the necessary bandwidth , or A ; 1.3�m. Since both dispers ion and electromagnetic compatibility , smaller attenuation characteristics improve at size, and non-electrical interfaces with A > l�m, there is a strong reason for patients . development of sources , detectors, and optical fibers for optimi zation at these The mo st recent meeting emphasized the longer wavelengths . An added benefit is rapid progress of fiber optics into the slightly larger dimension of compo applications . Fiber optics has moved nents which should affect strength and from the pro of-of-technology stage to reliability . Sources and detectors system-definition and economic-evalu still re quire major improvements in ation stages . The next several years efficiency and speed to match component have been forecast as years of rapid capabilities at the present wavelengths commercialization . Problems foreseen of interest. Progress along these lines have shifted from the problems of feasi has been encouraging . bility to problems of reliability and to difficulties associated with the deve lop International Electrotechnical Commis ment of performance criteria and stand sion Subcommittee on Fiber Optics . A ards . member of the NTIA/ITS technical staff was appointed as the Chief U.S. Delegate As Chairman of the Applications and to the meeting of the International User 's Working Group , the ITS represen Electrotechnical Commi ssion (IEC) , tative assists the com mittee in acquirlng , Subcommittee on Fibre Optics . The IEC analyzing , synthesizing , and disseminating deals with components and telecommuni fiber optics information concerning the cation systems in contrast to the CCITT , efficient use of the nation 's telecommuni which is a treaty-related telecommuni cation resources . Summary Reports of cations committee ; i.e. , the CCITT is the meetings are prepared and supplied to sponsored by the State Department and attendees . deals with telecommunications; the IEC is sponsored by industry and deals with Dispers ion Characteristics for Optical telecommunication hardware and systems . Fibers at Longer Wavelengths . A series The flow of goods to domestic and non of studies were made to determine the domestic markets is influenced directly upper limits on bit rate for fiber by the U.S. position in the IEC . A optical sys tems . The constant push strong u.s. market position can best be toward higher transmission rates and acquired by working within the fra mework longer path lengths for fiber optical of the IEC , The subcommittee met in cable has required close attention to Florence in June , 1978 . those fiber structures and material properties which relate to lower attenu The u.s. introduced two key proposals in ation , greater coupling efficiency of an attempt to get an early start on the light into a fiber , and lower dispersion standardization of terminal devices for properties . As attenuation has steadily optical sys tems . The proposal that been dr iven to lower values , 2 or 3 dB(km , succeeded in gaining initial approval attention has recently turned to those was the one which would elevate the properties of the optical waveguide fiber optics work to full Committee which define the ultimate limit of the status . It is as yet a subcommittee data-handling capabilities of the fibers under the aegis of the Committee on or the dispersion characteristics of the Cables , Wires , and Waveguides for Tele optical guide . A series of theoretical communication Equip ment. If accepted at s tudies was made at ITS offering methods all levels of the IEC , the proposal for determining optimum refractive index would allow the new com mittee to deter profiles for multimode and monomode mine which terminal components (now fibers . Also , a method was obtained for forming sub-assemblies of fiber systems) finding the optimum operating wavelength would be subj ect to stand�rdization . for monomode graded-index fibers. These studies have been prepared for various The commercial availability of modules publications and for presentation at acting as interfac es between the elec several technical meetings. A brief tronic and the optical wo rlds has made review of the more significant results the standardization of these modules a is presented as follows . high priority item, Optical waveguide attenuation due to Fiber Optics Communications Glossary . Raleigh scattering reduces rapidly as Fiber optics communications (FOC) tech wavelengths increase . Scattering losses nology has evolved extremely rapidly , at A ; 1.3�m is less than 20% of the and Government procurement of systems scattering losses at A ; 0.85�m. Taking for operational deployment is on the into account the material , waveguiding , ;increase. ·Numerous standards wo rking and modal properties of an optical groups , in both government and the waveguide , it can be shown that pulse private s ector , are actively engaged in spread can be minimized for a variety of creation of per formance standards cover glass materials as operating wavelengths ing components and systems . Decades of 60 experience in other telecommunications The handbook is entitled "Design Hand areas have empirically demonstrated that book for Optical Fiber Systems ". It is the absence of a standardized vocabulary written primarily for the communications common to closely related standards engineer t�at has had little or no prior inevitably results in ambiguities among experience with fiber-optic technology . such standards. These ambituities may Fundamental , (yet practical) design and result not only in confusion for the performance data are presented for all systems designers and users, but also in of the components required of a trans increased and unnecessary costs to the mission system . The design procedures Government as the result of inadequately are also presented in a systematic defined procurement specifications . fashion , pointing out those to be fol MIL-STD-188-120, Military Communication lowed for both a power limited design System Standard : Terms and Deflnitlons and a dispersion limited design . These and FED-STD-1037, Vocabulary for Tele procedures are summarized in the accom communications , both coordlnated by ITS , panying tables as an example . The have been directed toward alleviating actual design process is iterative in these problems in a broad spectrum of nature (between the two regimes) . This telecommunications areas . FOC terms and aspect is illustrated in three appen definitions have not as yet been in dices to the handbook , where actual cluded in these standards . design examples are presented . Many technical terms , unique to this new The handbook will be published by the telecommunications field , have been u.s. Army , and should be available introduced from the discliplines of sometime early in FY 79. optics and physics , are new to practical communications , and are used with various meanings by manufacturers, researchers, and procurement agencies . In recognition of this problem and the need to at least begin standardization of language dur ing early formulation of performance standards , ITS has compiled a preliminary vocabulary data base during FY 78. This limited effort has been conducted , using DoC funds , with the goal of producing , within FY 79, an Addendum to FED-STD·d037. The plan is to prepare a computer-stored draft of the initial data base , to facilitate revision , and to circulate this draft among key wo rkers in the field , includ ing chairmen of all performance stand- ards working groups for review and additional inputs . A revised and en larged draft will then be submitted to a subcommittee of the Federal Telecommuni cations Standards Committee lFTSC} for final review prior to publication as a Federal Standard . Fiber Optics Handbook . During FY 77, a design handbook for optical fiber com munication systems was prepared by ITS for the u.s. Army , Communication Elec tronics Engineering Installation Agency (CEEIA) , Fort Huachuca, Arizona . The draft of this handbook was delivered to the sponsor for review and revision at the end of FY 77 . During FY 78, this handbook was revised , and completed for publication . The emphasis in the handbook is toward the microwave engineer and system; i.e. , it presents the design aspects of a fiberoptic transmission channel that might be used to replace an existing microwave link , or be considered as an alternative to a new link. The inter face requirements with existing communi cations equipment is discussed . 61 Table 2-2. Flowchart for System Analysis POWER LIMITED OPERATION P --- L L L L ---- REQ'D P d c s f m s '-...... � ...... l ...... Bit Rate ( R) ...... Compare ...... BER ...... 0"\ ...... N � L MU ODE DISTANCE T �i;� ��� D��p LIMITS t DISPERSION LIMITED OPERATION t T = PULSE WIDTH L = SPLICING LOSS s p = REQ 'D POWER INTO DETECTOR L = FIBER LOSS d f L = CONNECTOR AND COUPLING LOSS p = SOURCE POWER c s L = DEGRADATION MARGIN m Table 2-3. Optical Communications Design Flow Chart 1 2 3 Establish total bit-rate and If multip lexing is envisioned , Determine detector power required link length requirements . define channel bit rate . for each channel for required BER and for detector specified. SA Calculate anticipated repeater spacing based on fiber and splicing loss and on power r-+ coupled into the waveguide . This t-- • step also determines source 6 characteristics . 4 Determine the allowable total dispersion from range-bit-rate C) Choose acceptable value of w product which guarantees operation fiber attenuation , based on r- SB H cost and spacing considerations . at the repeater spacing already determined (Box 5) . Calculate required power into fiber at transmitter in order to accomplish desired repeater 4 spacing with due regard to all I-- losses. This step also specifies source characteristics. �7 8 Choose waveguide and operating If repeater spacing (Box 5) and *Descriptive supplement wavelength appropriate to the allowable dispersion (Box 6) are to this Flow Chart is acceptable value of attenuation incompatible for choices made in given on the next two (Box 4) and total dispersion Box 7 , return to Box 4 and modify pages . (Box 6) . selection . CHAPTER 3. EM WAVE TRANSMISSION in engineering tools . Predictions of transmission characteristics and system The ground, the atmosphere , and the iono performance are discussed in Section 3.4. sphere degrade radio waves in varying de Section 3.5 reports on applications of the grees, depending on circumstances. It is knowledge and tools to specific problems the purpose of the EM Wave Transmission of other government agencies , such as mine Program to study these effects and pro and forest service communications . vide models to the system designer that will aid him in providing more cost effec SECTION 3.1. WAVE TRANSMISSION tive and spectrum efficient designs. The CHARACTERISTICS phenomena which cause these detrimental effects on radio and optical systems are , Experimental determinations of the effect in general , frequency dependent; therefore , of the transmission media on electromag specific studies and tests are required netic wave transmission are reported in for specific frequency ranges and appli this section , in particular those effects cations. produced by the atmosphere . Some of the phenomena which effect radio Broadband Transmission in the 10-100 GHz signals and are studied in this program Range . The obj ective or-this ma jor in are : house project is to develop a complete and quantitative description of the trans 1. Attenuation by atmospheric mission properties of the atmosphere at gases, hydrometeors (rain, snow , hail , frequencies between 10 and 100 GHz . This clouds , etc . ), or ionization. description will be used to improve design models and provide engineering standards 2. Scattering by hydrometeors or for the effects of the transmission pro irregularities in the refractive index of perties on performance of wideband , high the lower atmo sphere or ionosphere . data-rate systems . Progress made on the experimental phase is reported below . 3. Refraction , ducting, and multi path , resulting from atmospheric or iono Frequency Extension Research . Simulta spheric layers. neous measurements of signal variability were made at 9.6, 28 .� , and 57.6 GHz over 4. Dispersion , resulting from fre paths of 200 and 740 m. Although the quency dependent properties of the atmo 57 .6 GHz signal showed some correlation sphere , ionosphere , and earth . with ambient temperature as would be ex pected , in general , the lower frequency 5. Scintillation of amplitude , signals showed greater variability. Digi phase, polarization, and angle of arriv tal data were transmitted at a 1 Gb/s rate al , resulting from turbulence and irregu using 30.3 or 59.1 GHz as the carrier . In lar structure in the atmosphere and iono both cases , bit-error rates were consis sphere. tently less than 1 in 108 except for times (such as intense rain) where the receiver 6. Reflection, scattering, multi synchronization became erratic . path, and lower atmosphere perturbations resulting from terrain and man-made A model for the effect of multipath on bit structures . error rate was developed which gives good agreement with direct measurements of this The effect upon any specific system of effect (Figure 3-1) . A paper entitled the above phenomena is not only highly "Experimental and Theoretical Assessment frequency dependent , but is also depend of Mu ltipath Effects on QPSK," describing ent upon the type of service required for this development is scheduled for publica the specific application . tion in IEEE Transactions on Communications, October, 1978. Instrumentation for obtain One driving force behind the EM wave trans ing correlgrams (us ing a 1 Gb/s QPSK mo mission program is the need for more spec dem) was developed . This will permit re trum space . Therefore , this progr�m pro solving multipath signal components to vides models, techniques, and information less than 1 ns and calculating channel to aid the system designer and frequency transfer charac teristics over a band of manager in their decisions for better spec about 1 GHz. trum use . A paper on deep signal fading (> 20 dB ) Experimental or theoretical determinations entitled "Fading at 9.6 GHz on an Experi of radio wave transmission characteristics , mental Simulated Aircraft-to-Ground Path, " or the channel transfer function , are re by H. B. Janes and M. C. Thompson was ported in Section 3.1. Measurements of published in IEEE AP , September , 1 978 . transmission media properties and analyses of collections of such data are inc luded SECTION 3.2. CHARACTERISTICS OF THE in Section 3.2. Section 3.3 describes the TRANSMISSION MEDIA development and testing of models which incorporate the transmission information This section is concerned with the study 65 .··· . .. � . 2 � � � :: - � . • ·�··�·· ·· " · . . ��x 10 � : )l; /\.! X� � : � : !3' � : • • :: :>QXX '!- : � #X �. � X:: )\1( "·X-,: ··?< X ." X X · •)< X X X • .• 181 ,-p< X . >. . a... •. • ?Ill' ·-- X' . • : jJ · - � ... .. i< � : · ·.: - ...c -41I . 0 10 ·�0o =�· ...c .;. 0 � :"o- 1 /6 87/ 77 Data lo.- o � X• •• X a_ �- 1/11/77 Data /N0 = lo.- Es 13 dB 6¥! - 0 l lo.- o- R=0.4 lo.- Cal culated 0'1 0'1 w L_ CT= 60 cm - Freq.= 1.5 GHz (]) 0-8� 1 s 1 t Multipath nd 2 Bit Overlaps ""- I -101 I I I I � I 1 1 o I I �� 0 0.4 0.8 1.2 1 . 6 2 .0 Normal ized ro und trip reflector separation, 2d /CT Figure 3-1. Observed and predicted bit�error probability versus round trip delay for 1.5 GHz indoor multipath experiment . " of transmission media to help those who needed in the assessment of atmospheric design , construct , or use telecommunica shielding capabilities . In the window tion systems to better understand the ranges (30-50 , 70-110 , 125-150 GHz) , mo le characteristics of the media and their cular attenuation is mainly due to water effects on radio signals. We first dis vapor and confined to the first five kilo cuss the nonion ized atmosphere and then meters . the ionosphere . A tractable propagation model for the air 3.2.1. Atmospheric Characteristics ma ss emp loys a spherically stratified atmo sphere ("onion-shell" model of thin quasi An extensive measurement series on the homogenious layers) to be amenable to com oxygen microwave spectrum in air has been puter calculations of five integrals : cu completed . Out of 228 spectroscopic para mu lative attenuation (i.e. , transmittance ), meters , the most significant 132 have been radio range , curved path length , and noise measured with accuracies in the 0.5 to 3 temperature due to upwelling and down percent range . we lling radiation . These integrals are evaluated by numerical integration . Re The improved spectroscopic data base char sults of this kind were published in AGARD acterizing the EHF properties of air was CP 238, 44/1-18 (1978) . Figure 3-4 shows integrated into a radio path modeling the excellent agreement of the computer scheme that predicts various propagation simu lation with reported values for clear behaviors. air zenith attenuation . Atmospheric Medium Characterization and Orbiting Standards Platform (OSP) Prelim Modeling of EHF Propagation in Air . -rE marl� In the continuing cooperative is possible to predict the behavior of an program by the Communications Satellite EHF (frequencies up to 300 GHz ) radio wave Corporation (COMSAT) , NASA 's Goddard Space transversing an assumed clear , inhomoge Flight Center (NASA/GSFC ) , the National neous , nonturbulent atmosphere at various Bureau of Standards (NBS ) and NTIA' s slant path angles 8. Mo lecular absorption Institute for Telecommunication Sciences spectra of ma jor (o , H 0) and minor (e.g. , (NTIA/ITS ), a preliminary definition of 2 2 o , CO, N 0) air constiEuents cause fre the OSP has been accomplished . Briefly , 3 2 quency dependent signal attenuation , phase the proposed Orbiting Standards Platform delay , ray bending , and medium noise. The (OSP ) is the equivalent of a combined interaction between radiation and air is field-strength meter and signal generator expressed through a complex refractivity to be placed in orbit to meet the need for N, which is a function of frequency v, a readily accessible, relatively economi total pressure p, partial water vapor cal , calibration facility for earth sta pressure p , temperature T, earth magnet tions , large aperture antennas , and satel ic field s�rength H (o -zeeman effect) , lites . 2 and trace gas number densities . The N calculation takes into account 36 o lines , A preliminary description of this OSP was 2 6 H o lines plus a nonresonant specErum, distributed with a questionnaire to a sam 2 and , if needed , includes trace gas spectra pling of the private , commercial , and (> 100 o , 2 CO , 64 N o lines), which are government organizations that might con 3 2 generally weak . stitute an OSP user community . The re sponses to this OSP survey verified the The oxygen microwave lines split into assumption that the manufacturers and many components under the influence of operators of satellite system elements, the earth 's magnetic field . The compo scientific research organizations , and the nents are spread max . + 2 MHz around the radio wave regulatory agencies would , in unperturbed line centers , which become fact , consti tute an OSP user community. noticeable at altitudes , h > 40 km (see Further , this sampling suggests the com Figure 3-2) . A consequence of the Zeeman munity is strongly supportive (89% of the splitting is an anisotropic , polarization respondees) of the OSP concept and has dependent, complex refractivity N. Radio specific needs for the proposed OSP capa path modeling in the frequency bands bilities . Further , the user community v = 50 to 70 and 118 .8 + 0.1 GHz requires identified specific scientific studies the correct refractivity N(v, H, h) of that should be carried out by an OSP . They air for the height range , h 40 to 110 km . also identified the need to fit the OSP A straightforward , consistent , calculation into the present frequency allocation sched scheme was developed . ule on a noninterfering basis (OT Tech . Memorandum 78-249, February 1978) . Assuming a distribution of the gas vari ables for neutral air as a function of The OSP definition to date includes the height and the radio path geometry (ground specification of transmitting and receiving to-ground , aircraft, satellite , etc . link ) antennas of calibrated selectable gains provides the basis for calculating the and polarization , generated signals with various propagation effects . Figure 3-3 known stable amplitude and phase character gives an example of height contours for istics , calibrated circuits for the anal constant attenuation rates as, for example , ysis of received signals, and is highly 67 ,- a0= 0. 109 1+(56265 MHz) 0.10 Some as 1-, .XE except a0= ...... 1.0 0.424 CD "0 c -0 0 :J .& 0.5 0 -I -2 0 2 Frequency Deviation, MHz I I I 100 - 1- h= km (57164 MHz) 76 US. Std. Atm. H = 6 · I0-5 T (0.032 195.1 1- Po, K) .XE - '-5- CD :g. - c - .Q - - 0 . :J - -a} � - u v y -I 0 2 Frequency Deviation, MHz - Figure 3-2 . Examples of 02 -MS Zeeman patterns for 1 and 25+ lines at h = 55 km (p = 42.5 Pa and T = 260.8 K; U.S. Std . Atm . 76) for two magnetic field strengths , H = 3 (left half) , H = 6 (right half) x lo-5 T, and the unsplit line , H = 0. Zeeman patterns TI - and a = a+ + a- for the 7 line at an altitude , h = 100 km . 68 us_ \ \' Std. Atm. 76 I + ' \ I (02 H20 ) I \' ' ·\. I / "" \ dB/km _,/ / ->:::E /' �, \ ....__·-- oooo _.,.- ' .!:: / +- ""' .!:: _.....-/ 0'> "(L) � m I 1.0 ·� 001 01 0 20 150 Frequency (GHz) Figure 3-3. Height profiles of constant attenuation rates (0 - 10 dB/krn) for clear air. ,: ' r 21+ 2r 02 r CD "'0 <( � E .><: 0 1'0 I 0 C:: .Q -._] - 0 0 ::> c +- "" I ,.,�/__.\\ I _,- /"" '"""\ A{IOO%)Response)- A{5%) {H20- 0.1 20 50 100 150 Frequency (GHz) Figure 3-4 . Clear air zenith attenuation for 3 humidity models (5, 50, 100% RH at h = 0) . ... redundant self-calibrating and self 28 GHz signals will be coherent since they monitoring [Proc . Symposium On Antenna are derived from the same fundamental Applications , September 1978) . The OSP source . would traverse the geostationary orbit and be capable of measuring up- and down The 19 and 28 GHz beacon transmissions link earth station signals, internally from COMSTAR beacons Dl , 02 , and 03 are verifying the measurements, and telemeter be ing analyzed to learn the useful channel ing the results , Figure 3-5 . Parameters bandwidth at microwave and millimeter-wave wh ich are to be measured are primarily carrier frequencies . Government , commer related to the radiators of the communica cial , and scientific interest in transmi s tions system and include effective isotro sion through the atmosphere at frequencies pic radiated power (EIRP) , gain-to above 10 GHz derives from the potential temperature ratio (G/T) , gain , pattern , for employing this portion of the spectrum cross polarization , transmission path pro for satellite communications and the pro perties , and sidelobe structure , the lat mi se for frequency extension . Figure 3-6 ter including both amplitude and polariza shows the 10 foot receiving dish with the tion characteristics. receiver front-end at the prime focus used in the experiment . Figure 3-7 shows the A companion earth station serves to per one major source of signal Impairment ; form approximately the same function with i.e. , a rain event on the performance of up- and down-link satellite signals and an earth-satellite communications link . also to provide means for periodic re The correlation between received signal calibration of OSP . It should be empha strength and rain rate provides information sized that OSP does not act as a relay on the temporal variability of attenuation . station in the sense of a commun ications satellite (which receives , amplifies , and In most satellite communication systems , re-transmits a signal containing certain the signal received by an earth terminal information) , but rather is a remote stan is redistributed to various terminals on dards laboratory which receives or gener the earth . A terrestrial link operating ates a signal and telemeters relevant data at 28.8 GHz has its transmitting antennas about that signal . Processing would be located about 30 m from the 10 foot dish done by a designated government agency used in the 19/28 GHz COMSTAR satellite such as NBS or by the user himself , as beacon experiment . This terrestrial link appropriate. provides information on amplitude and de lay distortion signal impairments caused Satellite Propagation Observations at � by the same meteorlogical events , and near -----and 28 GHz . Future domestic satellite ly the same frequency , that effect the communication systems carrying high den- earth-satellite link . Figure 3-7 also sity traffic will use frequencies up to shows the received signal strength on the 30 GH z because of the presently greater 28.8 GHz carrier used in the terrestrial bandwidth available and because these fre link for the same rain event observed on quencies are not currently being heavily the 28.5 GHz carrier on the earth-satellite used . link . Beacons at 19 and 28 GHz on several domes Depolari zation and Frequency Re-use . Fre tic geostationary satellites have been quency re-use by introducing dual orthogo launched . The objectives of this ITS pro nal linear polarizations or opposite-sense gram are to monitor these beacons and circular polarization has the potential for collect attenuation and phase information. nearly doubling the available assignments The data will help to determine minimum in the radio spectrum . This raises the power and other performance margins needed possibility of an increased number of as for future satellite communication systems signments , such as additional TV stations operating up to 30 GHz . within a given geographical region . That could have a strong economical and social Colorado is an excellent location for data impact in the U. S. collection from the 19 and 28 GHz satellite signals since currently there is no other Of course , a full doubling of the avail site planned west of the Mississippi , and able assignments by frequency re-use could the Colorado site should provide optimum not be accomplished because there can be reliability from elevation angle considera technical advantages of one polarization tions. over another in some frequency bands . Further , in some frequency bands , there The satellite beacon transmissions will are propagation mechanisms which change a originate from three satellites, each with transmitted signal 's polarization . This a 19 and 28 GHz beacon . The 19.04 GH z bea depolarization can arise from the scatter con signal will be switched between two ing , reflection , and diffraction of radio orthogonal linearly polarized (i.e. , verti waves by : irregular terrain , rainfall , cal and horizontal) antennas at a 1 kHz clouds , and fog as we ll as the ionized rate . The 28.56 GHz signal will be trans layers , turbulence , and refractivity stra mitted continuously from a linearly polar tification of the atmosphere . The basic ized antenna (vertical only) . The 19 and requirement for assessing the impact of 71 SBS-8 ATS -3, SMS-1 50 LES-8-====-=���������=--===-=-=-=--=== ANIK 'CANA 0 ) CAN ) ADVANCED WESTAR===------CDUSMTE DOMESCH(uTsIC� WESTAR I US DOMEST IC COMSTAR 202 WESTAR CBSS COMSTAR II201 US DOMESTIC US DOMESTIC 40 COMSTAR-C SM S (NOAA ) I US DOMESTIC �• . I US DOMESTIC SATCOM I GOES- I ror ATS-1 / w - __.J BRAZILSAT 30 lCl . z: FLEET SATCOM US DOMEST IC cl:: TORS BRAZILSAT z: BRAZ ILSAT SATCOM -C.-- , 0 AN I LES-9 K.--- I 1- US DOMEST IC <:l:: TORS ------. > LES-6 SATC 20 w _____j INTELSAT I � �� =l __.J s w --.) INTELSAT I US S ���� 1 N S�� '. ���� i��---- INTELSAT IV� �� \ ��� I ) INTELSAT 10 0 350 330 310 290 270 250 230 210 190 170 150 EAST LONG !TUDE GEO-STAT I ONARY SATELLITE LOCAT IONS AS SEEN FROM BOULDER PRESENT PLANNED • o Figure 3-5 . Orbiting standards platform illustration . Cll ::l 0 0 -H \.0 I M 73 3/6 /78 1730 HR 1815 1900 1945 2030 36 -. Ra in Rain Event mm /hr 0 .....___. '-- I I v-----_,.._ JV ! ,.-...... c-=J ..__ I r--''====1 -18 I � Te rrestrial link Ka 28.8 GHz �F------(dBm) _ -30 -106 Earth -..] � Satellite link COPOL ( dBm) 28.56 GHz -118 -134 Earth Satellite link XPOL (dBm) 28.56GH� 146 Figure 3-7 . Received signal on tertestrial and earth satellite link versus time during a rain event . Satellite beacon signal received from COMSTAR Dl beacon at 1280 west longitude . depolarization upon frequency assignments appears to .�e extending the techniques is our ability to predict both the amount (that were successfully applied to terrain) of depolarization and its likelihood of to the atmospheric situation . occurrence . Calibration of Water Vapor Measurements . The likelihood of occurrence is directly During June 1978, an ITS model 7 refracto related to the occurrence of: terrain meter system was operated in support of irregularity , rainfall, clouds , turbulence, lidar measurements of atmospheric water and stratification . Descriptors of terrain vapor . Simultaneous measurements of re are widely available, at least for the fractivity , temperature, and pressure were U. S. , and this project 's efforts have ad recorded on magnetic tape in flight. From vanced the prediction of rainfall attenua these data , water vapor profiles will be tion due to rainfall (E . J. Dutton and calculated to provide calibration of the H. T. Dougherty , "Estimates of the Atmo lidar instrumentation . Twelve flight peri spheric Transfer Function at SHF and EHF," ods were conducted near Langley Field , NTIA Report 78-8, 1978; H. T. Dougherty Virginia , to altitudes up to about 4000 and E. J. Dutton , "Estimating Year-to-Year meters using a single engine aircraft Variability of Rainfall for Microwave (Figure 3-8) . Applications ," IEEE Trans . Comm. , August , 1978; E. J. Dutton and H. T. Dougherty , Microwave Intervisibility Propagation Los s - "Year-to-Year Variability of Rainfall for Measurements. An experimental program rs Microwave Applications in the U. S. A. ," being planned to examine feasibility of a submitted to IEEE Trans . Comm. ) and of millimeter wave system for determining in stratification (H . T. Dougherty and B. A. tervisibility of players in simulated com Hart , "Tropospheric Stratification and bat exercises . Frequencies in the 10 to Anomalous Propagation ," AGARD Symposium 40 GHz band will be used to observe vari Proceedings on Aspects of Electromagnetic ability and predictability of path loss Scattering in Radio Communications , for distances from tens of meters to sev Cambridge , MA, October 3-7, 1977; and eral kilometers , over different types of H. T. Dougherty and B. A. Hart , "Recent terrain , and as a function of position Progress in Duct Propagation Predictions ," below optical line of sight . Mobile ter submitted to IEEE Trans . Ant . and Prop . minals will be used , first in Colorado and 1978) . later at Ft . Hunter-Liggett , California . The prediction of the amount of depolari 3.2.2. Ionospheric Characteristics zation is directly related to both observed and Effects depolarization data and depolarization theory. Almost all of the observed depo Recqvery of Ionospheric Ducted Signals larization data due to terrain effects was from an Artificially Induced Scatterer . obtained in the 1930's and 1940 's when the An artificially induced scatterer at iono question of polarization (vertical , hori spheric heights can be generated by the zontal , or both ) for TV broadcast was being very high-powered HF transmitter at settled . This is now clearly in need of Platteville, Colorado . Rome Air Develop summarization and correlation with theory, ment Center (ETEI) , Hanscom AFB is sponsor and will be the subject of continuing pro ing a program to reactivate the ionospheric ject efforts . Most of the depolarization modification program and to perform a data due to atmospheric conditions (rain series of experiments to determine if iono fall, clouds , turbulence, stratification) spherically ducted signals can be reliably is limited to forward and back scatter reflected from the field-aligned scatters (8 = oo or 180°) . Faraday rotation data generated when a very high rf field excites has been long available and well correlated the plasma . These experiments were de with theory , particularly at VHF and lower scribed in a special issue of Radio Science , frequencies at which it is a dominant de November 1974, which wa s devoted to Iono polarization mechanism. spheric Modification . By mid-July 1978, the Platteville two megawatt transmitter With the exception of the Faraday rotation facility had been renovated after almost or depolarization by ionized layers , the five years of inactivity . As in earlier available theory for depolarization is very modification experiments , the diagnostic limited . The most advanced , that for ter ionosonde is located about 26 km west of rain effects , lacks accurate correlation the Platteville transmitter and also guides with data . The more currently interesting the modifier in frequency to interact with theory (depolarization by atmospheric con the plasma at the appropriate heights. ditions such as rainfall , clouds and tur bulence) is restricted to forward and back Since the irregularities generated in the scatter (8 = 0° or 180°) . Continuing pro plasma by the HF energy are aligned with ject activity will be concerned with ex the earth 's magnetic field , the signal re tending the theory for depolarization by flection from the modified region will in atmospheric conditions to that for arbi tercept the earth at a loci of points south trary scattering angles (0° < 8 < 360° ) of the region determined by the .height of required for application to frequency as reflection . The most likely propagation signments. The most promising approach path for ducted signals is believed to be 75 '} -..1 0\ Figure 3-8 . Single engine aircraft equipped to make simultaneous measurements of refractivity , temperature , and pressure . the lower boundary of the F-layer , wh ich Also dur ing the mid-July experiment , time varies in height from about 180 to 220 km and frequency transmissions at 5, 10 , and over a diurnal cycle . 15 MHz were mo nitored and recorded to deter mine if conditions may permit one of thes e Figure 3-9 shows a sample of a long de signals to be launched in an RTW mode . layed signal at approximately 140 ms time Transmitters geographically to the south de lay. The Platteville transmitter gener of Platteville on these frequencies are ated the signals which consisted of two , located at Hawaii , India, China , Japan , 1 ms pulses separated by 5 ms at a repeti Argentina , and South Africa . At Los Alamos , tion frequency of 5 per second . The re one or more of the frequencies from WWV at ceiver was located at the Erie site . Fort Collins , Colorado , can be observed at Strong backscatter signals are apparent anytime , which provides the reference out to about 80 ms in delay with discrete time to measure delays of any other re echoes showing at about 38 and 53 ms . ceived signal . Of the few hours available Because long delayed signals are difficult when the modifier and the standard fre to detect and appear usually for only short quency signals were appropriate for possi periods it is hoped that the scatterers ble ducting , there were real time observa produced by the high powered transmitter tions of signals with delay times corres will permit much longer periods for obser ponding to \tJWVH in Hawaii and JJY in Japan . vations . If true , these observations Magnetic tapes mus t be reduced on the com wi ll provide a better understanding of the puter in order to know the degree of corre propagation mode and launching techn ique lation and to identify all stations . to achieve the long delayed signals and determine if they are induced elevated Dur ing the next series of experiments modes. scheduled for late September 1978 , the FM/CW transmitters will attempt to launch The initial receiving location selected was ducted mode s to be ejected and detected at Los Alamos , New Mexico . Other locations at the receiving sites . will be tried to study the effects of path geometry on signal parameters. In order to Efforts on this program will continue in establish a transportable receiving ter FY 79 with other transmitter and receiving minal , the equipment is housed in a 19- stations employed . The degree of success foot trailer . An 8-e lement array of a and predictably of establishing ionospher ic long-wire traveling wave (Beverage) antenna ducting channels will determine if long is used . This long-wire array provides range radar for detecting ballistic mi s adequate performance over a wide bandwidth sile launching as we ll as a communication (5 to 32 MH z) and is easy to transport and network could result . install since elements are only one meter above the terrain. SECTION 3.3. DEVELOPMENT AND IMPLEMENTATION OF EM WAVE Although around the world (RTW ) signals TRANSMISSION MODELS are often seen , and are presumed trans ported via an ionospheric duct, little is Information about EM Wave Transmi ssion known about their propagation character Characteristics and the characteristics istics , particularly the mechanism for of the transmission media are incorporated launching a RTW mode . For the first test into engineering mode ls . These mode ls are series, two FM/CW transmitters capable of being developed for users within and out sweeping over a frequency range of 6 to 30 side government . As in Section 3.2, we MHz were in operation , one at Ava , New first discuss the non-ionized media cases , York , by the Air Force and a second at Lost and then those primarily influenced by the Hills , California , by Stanford Re search In ionosphere . stitute (SRI) . In addition to the Los Alamos receiving site , SRI used a receiving 3.3.1. Atmospheric Transmission Mode ls station located a few miles from the trans mitter to initially measure direct back Propagation Models and Data Bases . Over scatter signals from the modified region . the years , NTIA has developed many propa The data collected from the swept-fre gation models for a variety of telecommun i quency sounders dur ing the series of ex cation problems . This year , a project was periments in mid-July supplements the continued to provide a unified data base earlier data providing information on for propagation mode ls to support a wide scattering cross section versus height and range of anticipated communication concept , time of day . From this , some knowledge of design , and evaluation situations based on the amplitude of the recovered signals can current and previous works . This is a be obtained so that propagation losses of data and techniques bank wh ich will con the ducted signal can be calculated . Later solidate the results of telecommun ication tests are planned using pulse transmitters. research into an overall data base , in If the injection and recovery efficiencies cluding both atmospheric structure from are sufficiently high to enable detection models and measurements , and algorithms of multiple RTWs , then propagation losses for translating these into performance pre in the duct can be directly reduced . dictions for specific system applications . 7 7 5 ms Long Delayed Signal Transmitted from Platteville, Colorado � --1 Receiver at Erie, Colorado 09/13/78 Transmitted Signal Envelope PRF 5/sec C 600 Mw Peak ,_.F-1t---D-requency = 13 .75 MHz UT ;; i E .� .,_ .. = ...E.S .. 1!1 .... I> _, ...... "'"' ;;, g,o -..] "' 00 v� ·u> ...... """' !� \N��I'\_ - �om � - 0 20 40 60 80 100 120___..__.__, 140 160 00 · Delay Tl.me � "'"'----.From Tr�gg. er -----; �� (rns) Figure 3-9 . Sample of long delayed signal (137 . 5 ms) . In FY 77, concentration was on the fre estimating the performance of a communica quencies between 10 and 100 GH z. In FY 78 , tion link over the same paths. The mea efforts to expand the data base down to surements were made during the daytime in 100 MH z have been undertaken . The various order to restrict the measurements to the models and algorithms are intended to be surface wave mode of propagation . A com upgraded as new and/or better information panion project compares the measurement be come s available . In succeeding fiscal results to propaga tion predictions made by years , it is anticipated that a comprehen program Y'IAGNER, a theoretical prediction sive library of information will exist program (R. H. Ott , "An Alternative Inte wh ich will cover frequencies from VLF gral Equation for Propagation Over Irregu through optical . lar Terrain," Radio Science , Volume 6, No . 4, April 1971) . A report entitled "A Preliminary Catalog of Programs and Data for 10-100 GHz Radio The second obj ective was to describe pro System Predictions ," has been published as pagation loss measurement techniques which OT Report 78- 141. An example of what is could be used by others to make similar presently available in the beginning cata me asurements in the LF-MF (low frequency log is shown in Figure 3-10. medium frequency) bands . Thus if program WAGNER is unable to predict the propaga Computer programs and data bases under the tion loss values with sufficient accuracy , following four categories now exist in the then these techniques could be used to data bank : make field measurements of propagation loss and/or signal strength instead of Category l. Computations of Transmission making loss predictions with program Loss and Radar Returned Power . WAGNER . Category 2. Computations of Desired/ The third obj ective was to develop a pro Undesired Signal . cedure for making ground conductivity mea surements and me asure the conductivity Category 3. Computations of Atmospheric along the path that the propagation mea and Precipitation Parameters . surements were made . In order to make propagation loss predictions , program Category 4. Data Bases and Associated Pro WAGNER requires frequency , ground conduc grams . tivity , and path profile data for input . Two-dimensional path profiles are avail Surface Wave Radio Propagation Measurel able from topographic maps of the areas ments-rn�he 100 to 2000 kHz Band . Mea- where measurements are made . Ground con sureme nts of surface wave-propagation path ductivity data can be estimated from geo loss and local ground conductivity were logical maps and from FCC ground conduc made over four paths in the 100 to 2000 tivity maps (Fine , 1953) ; however , it was kHz band . The paths were of lengths up to reasoned that if the ground conductivity 52 km and were chosen to represent both could be measured along the path rather extreme and typical topography and conduc than estimated , then the influence of un tivity conditions for short communication certain ground conductivity values could paths within the U. S. The sites selected be removed from the prediction process. for the measurements were : Eliminating conductivity as a variable parameter allows the prediction program to 1. Canyonlands , Utah -- large variations be tested for its sensitivity to the two in topography with wet river bottoms dimensional path profile data and compared having sheer canyon walls to high , with the propagation loss measurements; flat plateaus; the measured losses are influenced by the three-dimensional terrain and not just the 2. San Francisco , California -- large two-dimensional path profile used in the variations in ground conductivity with predictions . The requirements for making rather level topography ; ground conductivity measurements were that they be made in situ without destroying 3. Santa Rita Range , Arizona -- a long the local ecology and that they be made ridge with little change in topography at each of the propagation loss measure along lines parallel to the ridge line ; ment frequencies . and Each site required approval from both the 4. Highland Range and Dry Lake Valley , local Federal officials having land juris Nevada -- another ridge with large diction and the regional Federal Frequency junipers, cedars , and similar vegeta Managers (in addition to IRAC approval) to tion. transmit on noninterfering test frequencies . The first objective of the measurements Once the site was selected and the trans project was to obtain propagation loss mitter location and the receiver measure data , over various types of terrain , which ment points were approved by local offi could be used to determine the suitability cials at the sites , the path loss and con of a propagation prediction program for ductivity measurements were made . The 79 Title : DEGP 76 Computes: Distribution of annual attenuation due to rain, clouds , atmospheric gases . PHIRAP = partial phase delay due to rain only to height H, in radians REVATUP = partial atmospheric attenuation to height H, in decibels ETADB reflectivity in DB relative to 1 KM (-1) at height H PH IRA total link pahse delay due to rain, oxygen and water vapor dispersion, in radians . REVTAU = total atmospheric attenuation on link , in decibels. Input : NS number of data stations . NF number of frequencies desired . IF NCLD = 0, the program performs computations with a built-in nonprecipita ting cloud distribution (subroutine cldbank) . If NCLD not = 0, a cloud attenuation distribution must be provided as subroutine CLDDIS . NA number of elevation angles desired . NH number of heights desired . If it is not = 2, get attenuation coefficient at surface only . Otherwise, do the whole program as usual. F = frequency in GHz . STAT = station identification , not to exceed 40 letters and numbers in length . P station average annual pressure in millibars . T station average annual temperature in degrees centigrade . RH = station average annual relative humidity as a decimal fraction . BETA ratio of thunderstorm rain to non thunderstorm rain, see RICE , P.L. and N.R. Holmberg (1973) , cumulative time statistics of surface point-rainfall rates , trans . IEEE com . soc , 10 , Oct . R = rainfall rate in MM/HR , corresponding to a give percent of an average year (RELI) . HTOP = cloud top height in kilometers corresponding to a given percent of an average year (RELI) . RELI (CURRENTLY IN DATA STATEMENT) = percent of an average year of interest (time availability per year) . THETA = elevation angle of earth station antenna , in degrees . H = height above surface in kilometers . Limi tations : Not valid for satellite/earth trojectaries where the elevation angle to the satellite is less than 5° . Current Status : Does not yield smooth output; i.e, the output distribution is not smooth , and should also be graphically displayed , to be of maximum usability. Re ferences : Dutton , E. J. , Earth-Space Attenuation Prediction Precedures at 4 to 16 GH z (soon to be OTR ) . For more information contact: E. J. Dutton Figure 3-10 . Sample info�mation page from catalog . 8 0 transmitter was fixed at one end of the power fa ding , and equipme nt mal funct ion . path and measurement points accessible by To be comparable with prediction methods 4-wheel drive vehicles were selected along now in use , the data will be analyzed to a radial from the transmi tter over the predict Rayleigh fading incidence occur terrain of interest. The receiver system ring during the worst 30-day period . was transportable to each measurement po int and was tuned to sequentially re The project is sponsored by the U. S. ceive CW transmissions on each of the five Army Comm unication Command in view of in or six test frequencies . Following the creased pressure to change military radio propagation loss measurements along the systems to operate in the 15-GHz band ent ire path , ground conductivity measure within areas of high microwave spectrum ments were made at each of the test fre usage . quencies at ea ch measurement point. Air Navigation Aids . A knowledge of ser The raw data were digitally stored on mag vice and interference ranges associated netic tape for data reduction on a batch with existing and future air navigation computer facility at Boulder . The reduced aids is an important part of the FAA's propagation loss data will be analyzed by spectrum planning effort . Propagation a companion project to determine the dif prediction capabilities developed by NTIA ferences between the WAGNER predictions as part of the Air Navigation Aids pro j ect and the measurements at each site and fre are utilized to provide much of this in quency. formation . As an example from the measurement program , During 1971-1973, an air/ground propaga Figure 3-ll shows the transmitter site for tion model applicable to irregular terrain the Canyonlands measurements and Figure was developed by ITS for the FAA and was 3-12 shows the topography of the Canyon documented in detail . This IF- 73 (ITS lands . The path profile of the radial FAA-1973) propagation model has evolved along which measurements were made is into the IF- 77 model, which is appl icable shown in Figure 3-13 . The measured signal to air/ground , air/air, ground/sate llite , and noise levels�2 MHz along the path and air/satellite paths . It can also be are shown in Figure 3-14 . The correspond used for ground/ground paths that are ing predicted signal levels are shown in line-of-sight , smooth earth, or have a Figure 3-15. The measurement procedure common horizon. During 1978 , documenta and results are to be published in an NTIA tion for IF-77 was published in the form Report entitled "Surface Wave Propagation of two reports. One is an "Application Measurements in the 100 to 2000 kHz Band." Guide" wh ich details the plotting capa bilities of the ten computer programs Multipath Fading on Long 15 GHz Paths . which utilize the IF-77 mode l. Two sample This project is designed to acquire data , plots are shown in Figures 3-17 and 3-18. analyze it, and develop empirical para The other report documents the "Extensions" metric relationships for designing long to the IF-73 model to develop the IF-77 (greater than 50 km) line-of-sight micro model. wave links . The largest part of the data base for models now being used was obtain The work currently underway on the project ed on short paths , for relatively short is in two directions : ( l) Pr oduction of periods , and at frequencies between 4 and computer generated propagation or inter 6 GHz . Although there is some data at ll ference predictions for the FAA is on an and 15 GHz , much of these data were ob as-requested bas is . Part of this work is tained using recording techniques which being used by the FAA to deve lop new stan did not provide adequate time resolution dards and to publish new handbooks . ( 2) for obtaining short term statistics . The compariso� of predictions with experi mental data and with other models is con Data acquired on this project will be ob stantly going on . During 1978, a report tained using carrier frequencies of 8 and was begun which compares over 300 predic 15 GHz . If possible, the data will be tions made with the IF-77 model with data acquired on three long paths (90 km , 93 km, and with other models . An example of one and 132 km) which converge at Mt . Corna , of these comparisons is sh own in Figure Italy (see Figure 3-16) . The 93 km path 3-19. The report should be published next is primarily over water . The data acqui year . sition period will be one year beginning in September 1978, if possible. Recording Propagation prediction capabilities deve l of data will be done using digital magnet oped as a part of the Air Navigation Aids ic tape after the data are first prepro project are frequently utilized to provide cessed by computer in one hour blocks. predictions for other projects . One such The data will also be recorded on strip pro ject is the Ground/Air Propagation chart to aid in categorizing fading mech Prediction project in wh ich service cover anisms . This categorization will be done age predictions for a missile command/ in an attempt to separate signal level destruct transmitter were deve loped for variations into incidence of Rayleigh the Pacific Missile Test Center (PMTC) . fading , rain attenuation , other forms of These predi ctions were made with a program 81 F igure 3-11 . Canyonlands transmitter site looking along the measurement radial . 8 2 ro w Figure 3-12 . The Canyonlands site as viewed from Dead Horse Point . The radial crosses the three plateaus on the left. A. 25oo ...... --- -�---�----�-----,----· () '- � 1800 � 1600 1400 1200 1 1000 0 10 40 49. b CANYONLANDS Tl CANYONLANDS RI Figure 3-13. Path profile plot for Canyonlands , Utah . 8 4 �.'�.-- '2• • 1.8 • l,f:"J. = X = SIGNAL X 0 NoisE X X X l � · ,.� o o� m>' ' ) X . • X X X o· l X ,, ... X X . • 'i X X n ·SC � ' X X I X \''. f . . X Ill t ' X ItI n· xx • Ill ,.. '... ,. .. . � 'I � ., ,.., " " " ,. " .; ...... " .;,; "' J ,. " ..., .. ..,, .. " �0 v • . . . • " .. " .. " -.:�. " 2: 1.5 H ... : :s·:.�;:E ... li:!.. :�E�E�S ., � �'; :':.. A.' : S ;":2. ::: �;oz Figure 3-14 . Measured recei�ed signal and noise levels , Canyonlands patli , 2.0 MHz. 8 5 F: 2. 00, HA= O. OOM, HAR= O. OOH DATE 78/03/31 . TIH£ 12. 15. 27 . I .tO 130 120 110 \ 100 \ \ ao �'\ 70 1\ ) l( l( 60 �j :� � so ' � �., ['r�� ··, f� .£0 0 I 0 20 .£0 .£9 DISTANCE IN.KILOHETERS Figure 3-15 . Preliminary plot of p�opagation loss measurements made at Canyonlands, Utah, site ( X ) and the predictions of loss from WAGNER (solid line) for 2 MHz . 8 6 Mt. Paoane IIa Mt. Corna Cl nda 15. 0336 iiH;t. Ve N :c E c:J ...::.:: C) en ca • c.Q ..... � • (¥) Ln ...... Mt. Cimone Figure 3-16 . Path locations for the long path 15 GHz multipath fading tests . 87 R�o�n Codt 71/06/27. 16. 43. 06. TRANSMISSION LOSS, ATC ...... rree SPCIC8 rre��o�ency 125. MHz Smoo t� eortk 957. 1 50. 2m) f s s Poiorizot ion Horizontal H f t ( 15 . Go in 0. 0 dB i Distance in km 1oo 2qo 3oo 4oo 590 6po 7()0 800 900 1 00� 0 II 120 H in feet (meters) � ,_...... :.::·!······ · ···· - 2 · � :�� . - -,··- � - · -··· ··· :::.: - ·· - · ····•··· 130 -=i"\_ JC >-""' !- ·'"'0 ,000 (15, 240)-+---l " --� 45,000 (13, 716 )"""" .... 140 \"\ �\\ '\: '� �"�� ::::.J- 150 --+---l \\\\[\\ \ "�"�"'�� �� ��:- 0,0���00 ���(9,: 144)���,,' _ 160 � \\\�\ \ \ \ \ \\ y� � 5,000 (7,620)---1---i c:: 0 \\ \ •"J O,OOO (6,096)_-+---4 170 ' !\ \ \\. \ \ \\ ,\ \ \ 5,000 (4, 572) \ 1\ !\ \��' \ \ !\ ...... \\ -LO,OOO _:o;;;:::: �;.,�,""� (3, 048) -+--l ::: "���--., 200 ���-4-�-��--� ��������������t--r-1 H in feet (meters)���� :::_::::::��I:S:5� 210 f-- 2 -����;:::R����� 5,000 (1, 524)-- v-- -- 220t-- :: � �-- -....;:����:::§�� 3,000 (914, f- _.- � - -- � - :""'-- � 230 - 2 ,000 (610 )::: --- --� __.v- !iii.:;;;��:::::: 1 ,500 (457) - _.-f--"" --�- ..... �� 240 - 1 ,000 (305 _....f.-- � � �� 250 500 (152)-- o 2' so 75 1 oo 12s 1!>o 1 rs 200 22s 2! o 2 s 3oo 3::" 3!io 3i5 .coo 425 4! o 4 '5 so Distance in n mi Figure 3-17. Transmi ssion losf curves, air traffic control . Samp le "applicatlons" plot . 88 n mi (74l .km) 77/07/13. 08. 45. 35 . Station separation 4 00. Run Code foc i lit� Vr.desirtd foc i lit� II Des i red ...... dB... TACAN VOLVME F' ru 39. 0 1150. ----- 5. 00HICt1. EIRP dBW MHz So•• OS des i red foc i lit� ft (9.1m) fss 50. 0 07. H I 30 95. 0 01. Po I or i z o t i on Vert icol I II II II I Desired path distance in km 50 100 150 200 250 300 350 400 450 500 550 0 0 . I I \ 30 .... I \ ...... I I ' I \ ...... 90 I ,\ \ 0 I \ I I ' .., I ' 25 "Q 80 � I \ c: I a I I .., I �,' ::J 7 0 � I \ ' c 0 I ·rl I ' 20 .c. I ' r ..... I ' I I• bO , \ I c: :I I I I I I I \ \ ... 50 . \ I I "Q l l ::J . I ..... I \ .co ..... \ I i I · I \I a 30 ···""'I 1 1 I ..... ""I I I ...... : I' ' a .:) \ �· � 20 ' u .. ' 5 � ; •• •• .. \ I 0 \ < .. v I ; . . i . •• I � ; 25 50 15 i 0 0 125 15 0 171 5 200 225 250 275 I 300 Des ired path dista�ce i� � IIi Figure 3-18 . Service volume , 'fACAN . Sample "applications" plot . 8 9 100�------�------�------�----�--� Direction of Flight -----. Altitude Flown - 2000 ft. Type of Aircraf t - DC - 3 Type of Fa c ility - VOR / Type of A C Antenna -Collins 37 J-3 A/C Loss between Antenna Rec.- 0 dB 90 8 H--·----lf------ll\f-\----+-----1 IF -77 Prediction ----- 5°/o ...... 50°/o ------95 % ( BOr-�------+------�------+------�----�4---� --�----l i f: 70 \ ::i_ aIf f \ CD u ) f! I c ;/ I ::J ;.:> -1 a. l -c 60 Ji '- 50 Distance to Station in Nautical Miles Figure 3-19 . A sample comparison of predictions and measured data , this one being an actual facility overflight . 90 modified to (l) approximate the circularly 3. 3. 2. Ionospheric Transmission Models polarized transmitter antenna pattern , and (2) include missile receiving antenna gain Computer programs developed by ITS for statistics for a random orientation in the predicting ionospheric transmission and calculation of signal level variability . the performance of HF radio systems are Figure 3-20 is a sample of the predictions used by government agencies and commercial provided . It shows the air space (service firms in the U. S. and other nations . A areas) in which different received power continuous program is carried on to up levels at the missile would be expected to grade and expand predictions services to be available for at least 99.9% of the fit users needs . transmission time . Normal day-to-day and hour-to-hour depar Hydro-Quebec is planning an extensive mod tures of critical frequencies (foF2) and ernization of its land mobile radio system . other ionospheric characteristics from ob Under this project, entitled Mobile Aids , served median values have a significant ITS wi ll devise computer aids to help the effect upon the range of useful frequen design of the new system and will supply cies on HF communication circuits . Even these aids in the form of computer programs greater effects result from disturbances able to operate at the sponsor 's facility. in the earth 's magnetic field and from certain forms of activity on the sun . In FY 78 , we have supplied the sponsor with programs to estimate received signal levels Development and Improvement of Prediction on point-to-point communications links , Formats . The ICA/VOA , in maintaining and from a mobile base station to a sequence improving its worldwide broadcast schedules of points along a road , and from a mobile on high frequencies , requires predictions base station to an entire area . All of of its expected broadcast coverage we ll in these use a file of digitized topography advance to prepare for its broadcast sched which is soon to be implemented . ules . Predictions have been delivered on schedule , and VOA continues to make occa In a project devoted to VHF/UHF Model sional use of their programs by remote Development for Urban and Rural communi access . Work has been done and will con cations , we completed an extensive study tinue to adapt the new HF predictions pro of what is known or surmised about propaga gram (IONCAP ) to VOA' s needs . IONCAP out tion in rural areas . The report that de put will be compared with HFMUFES (the scribes this study also discusses the present program) output , and both wi ll be Longley-Rice model of propagation and gives checked (by VOA) against monitoring re suggestions as to how it may be modified sults . to include an "urban fac tor ." 3.3.3. Terrain Models In other directions , this same project has begun assemb ling measured data into a com Ground Wave Propagation Over Irregular , puter readable form. The emphasis here is Inhomogeneous Terrain: Comparisons of on radio data (including its variability) Calculations and Measurements. A method in or near the UHF televis ion band , for for calculating the ground-wave field there is still controversy over what en over irregular , inhomogeneous terrain was gineering parameters one should use in developed by R. H. Ott, and several com this important part of the spectrum . In parisons with alternative analytical addition , the project now has underway the methods were made for idealized terrain preparation of several papers on the gen profiles like concave parabolas , sea-land eral subject of variability. sea paths , and Gaussian ridges . The excel lent agreement between methods like Fock The second phase of a study of Power Fading currents for concave surfaces , classical Statistics is underway . Sponsored by the residue series , an integral equation devel Electromagnetic Compatibility Analysis oped by Hufford , with Ott's alternative Center , Department of Defense , the purpose method based upon an elem�ntary function is to put on a firm foundation one aspect (closely related to the Sommerfeld Flat of the engineering design of microwave earth attenuation function) for the para links . Heretofore , calculations of the bolic wave equation provided encouragement magni tude of long-term (power) fading has for the usefulness of Ott 's method and the been based on techniques developed ten associated algorithm . years ago when there were few accumulated data at frequencies above 1 GHz. The research on this program in FY 78 ex tended and modified the original algorithm In this second phase we are collecting to and compared the computed field strength gether all the newly available data . We with observed values obtained on 9 separate will compare these data with the present paths shown in Table 3-1. The polarization day techniques and suggest whatever ad was vertical for all paths in Table 3-1 justments seem necessary. except the Buffalo path . As an example of the comparison between the predicted and measured field strength 91 Rur. Code 77/10/17. 16.li.54. Facility 99. 907. Power Availab le ir. dBW SAN DIEGO, HIGH ANGLE ··············• � 119 I r r I I I I I 22 • t Hl 20. 0 ft above surface Po larization Circular -125 S111ootll earth ----- �t3! 900 ' I .· I .· : • f . .· 800 ' .· 700 · & ...... ' c:: ! • I .. : • • c:: 600 • - : • I ., • • "0 500 / •' � y"' .... · .· · • 'V .... , • N . "' ...... � .. . 400 v"' · .· G .. . • i"' .· · ' .... .· "' . . '/', . - .. , 300 -.. "' 0 v � . ·...... · u ·· • :/ .. � .. : . 200 �� � -< �..r; Ji" . ·�...." ... ·· ...... · �_ ; 100 , �, ,, J.V':., .. · �···· " ...... � 0 .. A a a - - - . --·�--. - - . -- . - .. - . � - - - � A ------...... --- ·-- ..... - 0 QjstCBf\ C8 if\ f\ Mi Figure 3-20. Service areas for command/destruct transmitting antenna with high beam elevation angle . Table 3-1 . Program Waglin Comparisons Path Frequency Re ference Tran_s mi tter (WGR-TV) 59.75 MH Z Ring , A.D. (1958) Field in Buffalo , NY-over (horizontal strength measurement Lake Erie toward polarization ) survey for Association Cleveland of Maximum Service Telecasters, Inc. , Buffalo , NY , A.D. Ring and Associates , Washington , D.C. Transmitter (KCBS ) 740 KHz CBS Radio (1971) , north of San Francisco Field intensity measure Bay , south through San ments to establish per Francisco , over Santa formance of directional Cruz Mountains antenna rotation KCBS , San Francisco , CA , Report E 70704-A, CBS Radio , Columbia Broad casting System , Inc . Transmitter (KBLU ) in 560 KHz Contact John Heckscher , Yuma , AZ , beyond Rome Air Development Tinajas Altas Center , Hanscom AFB , Mountains toward Cambridge , MA Luke AFB . Transmitter (KBOL) in 1490 KHz Contact W. A. Kissick , Boulder , south over Institute for Tele Davidson Mesa communication Sciences , Boulder , CO Canyonlands, UT .120, .180, .410, adjacent to Canyon .510 , 1.62, 2.0 MH Z lands National Park From Mare Island , .120, .180, .410 , Contact W. A. Kissick , Valejo, CA south .510 , 1.62, 2.0 MHZ Institute for Tele over San Francisco communication Sciences , Bay over Marin Boulder , CO Peninsula Santa Ritas , NM near Greenvalley , NM and adj acent to New Mexico Experi mental Range Dry Lake , NE , Transmitter on east slope of Highland Range , over Highland Peak to Dry Lake Valley Colorado Mountain Data M. E. Johnson, et al. toward Berthoud Pass (1967) IER report number Campground IER 38-ITSA 38-2 93 versus distance consider the Luke-Yuma global grid of parallels and meridians path . RADC personnel made a number of who se ba sic value is 3 seconds . The pri field strength measurements in an area mary source of raw data for the present southeast of Yuma , Ar izona , using as a will be the so-called Standard Digital source the Yuma commercial broadcast sta Terrain Elevation Data Files being pro tion KBLU (560 kHz) . The path profile is duced by the Defense Mapping Agency . The shown on the lower portion of Figure 3-21 . DMA tapes are not in a usable format for The path cx.-osses a minor ridge (Vopok_i __ easily extracting terrain profile data. Ridge ) at about 45 km and , later on , a CONUS wi ll be covered by about 75 TOPOG higher ridge (Tinajas Altas Mountains) at tapes (1600 bpi , 2400 ' reels ) versus about about 65 km . The electrical ground con 110 DMA tapes . stant:s used in PROGRAM WAGL IN are shown in the upper right hand corner of Figure In FY 78 , the project has developed (1) 3-21. In Figure 3-21 is a plot of the software for generating TOPOG records and pr edicted path 16SS1solid curve ) in terms tapes from DMA Standard Files (PROGRAM of "DBU/KW" (dB above 1 microvolt per GENTOP ), and (2) a basic retrieval subpro meter for 1 kw radiated from a half-wave gram (ELVAT ) which, when given the lati dipole in free space ), together with mea tude and longitude of an arbitrary point sured DBU represented by crosses . The on the earth 's surface , utilizes TOPOG to predictions appear to agree very well with return the elevation of that point or in the observed values . forms the user that TOPOG does not contain the necessary data . Automated Digital Topographic Data Techni ques . The Automated Digital Topographic SECTION 3.4. PREDICTION OF TRANSMISSION Data Techniques project designed and will PARAMETERS AND SYSTEM PERFORMANCE improve a digital terrain elevation data base along with the related software . It Completed engineering mode ls for EM wave is primarily to be used by USACEEIA in transmission calculations are delivered to carrying out its worldwide responsibility sponsoring and requesting agencies for for planning , trouble shooting , and in their use . Following are representative stalling routine and strategic communica uses of these services. tion systems . Methods for predicting the performance of communication systems gen 3.4.1. Long-Term Ionospheric Predictions erally of frequencies above 30 MH z require terrain information derived from profiles The ICA/VOA requires regular predictions along a large number of potential propaga of " circuit" performance as an aid in plan tion paths (see Figure 3-22) . These re ning appropriately for the continuation of quire a rapid and accurate means of auto its world-wide HF broadcasts. matically generating these profiles from data stored on magnetic tapes or disks . The Radio Propagation Predictions project To satisfy this requirement , ITS has de provides the VOA every second month with signed a digital terrain elevation data HF circuit performance predictions for base (TOPOG) that: about 180 broadcast circuits 8 months in advance. For about 150 of these circuits 1. provides significantly greater detail (from Tinang , Kavala , Greenville , Woofer than can be obtained from the data ton , Monrovia, Munich, and Tangier) , the base currently being used by the predictions include selection of optimum sponsor; transmitting antenna . 2. can readily expand toward global CDC 6600 files have been maintained for coverage as additional data become local batch processing and , under the VOA available ; Time Share Service , they are available- for use by means of remote access from a 3. can be generated in a reasonably remote TELEX terminal. Program files have efficient way from existing and pro been prepared and maintained to help in jected sources of raw data; (1) preparation of input data for the pre diction program, and (2) to give great 4. can be utilized in an acceptably circle distances and bearings for arbitrary efficient manner in profile generation circuit terminal locations . Files are and other telecommunications applica also ma intained on the XDS 940 for inter tions; and active time-share access by VOA to the prediction program. 5. minimizes storage space requirements subject to constraints imposed by con In addition to VOA , there are other govern ditions (1) and (4) above . ment agencies and industrial organizations requiring Numerical Prediction Services. After a preliminary study in FY 77 of This project provides HF radio propagation several alternativ� methodologies of predictions and computer programs on a creating and returning datum from data cost reimbursable basis . bases , the result was a data base consist ing of the elevations at the nodes of a HF radio propagation predictions were pro- 94 120 DKM Sigma EPS 41.36 .020000 10.0 44.87 .00001 0 8.0 110 61.1 I .020000 10.0 72.55 .0000 10 8.0 83.00 .020000 10.0 100 � sor-���--�---+---r--�--4---� .::.::...... :::) (!) 0 Kilometers 83.0 WATER Figure 3-21. Path loss in dBU/Kw versus distance in km for a path with transmitte� in Yuma , AZ , over the Tinajas Altas mountains toward Luke AFB . 95 Figure 3-22. TOPOG tape areas for CONUS . 96 vided routinely to ITT World Communications , Figure 3-23 is a photograph of the instru Associated Press, NOAA/SEL , and the Ameri mentation van interior . All antenna pow�r can Radio Re lay League (for publication gain pattern measurement data are reduced in QST) . ITS made predictions for Sperry to plots onsite ; some are plotted in real Support Services (for the Coast Guard) , time . USDA Forest Service, the World Radio Mis sionary Fellowship , and for Phillips Pe Figure 3-24 is a plot of buried antenna troleum in support of the HF communications power gain; versus azimuth , relative to required in their operations . In addition , that of an above ground reference verti predictions were sent to the following cal dipole antenna . The elevation angle companies in support of HF systems design to the source of test site illumination is and were supplied to foreign governments , about 13 degrees . especially in the Middle East : BR Communi cations , Canadian Marconi , CCA Electronics, BOM Analytic EM Waves . Various subsurface DHV Incorporated , Sabre Communications , guided wave mechanisms have been analyzed Scientific Radio Systems , Singer Products for the Bureau of Mines . The primary Inc., TAI, Techno Gener Ltd . (Iran) . ATC applications have been in mine communica in Denver needed predictions for the pro tions , but some attention has also been jected reception (for midwest rebroadcast given to electromagnetic methods for non ing via cable) of VOA program� from the destructive testing of mine hoist ropes . east coast of the United States . Also The following specific areas have been under the reimbursable Numerical Predic studied during the past year . tions Services project , program tapes were sold to Granger Associates , Hayles Niblock The leaky-feeder communication technique International Ltd , Merle Collins Foundation , is presently under consideration for use Shape Technical Center , National Institute in mine tunnels . This technique normally for Telecommunications Re search (South utilizes a coaxial cable with some type Africa) , United Marine Electronics A/S of loose braid for the outer conductor . (Norway) , and Johns Hopkins APL . The pro The propagation modes of such a structure gram was provided without cost to the have been studied both numerically and Radio Research Laboratories in Tokyo . approximately using a quasi-static theory . By analyzing both circular and elliptical SECTION 3.5. APPLICATIONS tunnel models, it was found that the shape of the mine tunnel does not strongly affect The constant study of EM wave transmission the propagation modes. Mode conversion characteristics , the development of up-to can occur in leaky feeder transmission due date theoretical and empirical models, and to irregularities in either the cable or the study of real-world telecommunication the tunnel properties . Both controlled problems lead to state-of-the-art applica mode conversion as produced by the cable tions for telecommunication uses . This design and inadvertant mode conversion section deals with a variety of programs produced by tunnel wall roughness have which show the broad spectrum of applied been analyzed . The transmitting and re electromag�etic sciences . ceiving antennas are usually loops or short monopoles , and total transmission 3.5.1. Antennas and Radiation loss calculations have been made for both types . Pulse propagation and bandwidth Buried Antenna Studies--MX Phase II . The limitations for leaky feeder channels have ma jor part of the MX mobile antenna studies also been analyzed , and the bandwidths will be completed with a set of onsite are typically found to be quite large . measurements at the Luke-Yuma , Arizona , test site during September 1978. Trolley wire communications in mine tunne ls utilize a quasi-TEM mode of propagation Major tasks performed this year are as with forward current in the trolley wire follows : and return current in the trolley rails . In practice , discrete shunt loads on the - Completed final report for Phase I. trolley wire can introduce losses and reflections which limit the range of trans - Obtained instrumentation van , installed mission significantly . To extend the test instrumentation and support, systems . transmission range , a smaller "dedicated" wire can be utilized to provide a low - Developed and tested UHF antenna model attenuation mode of propagation which is for ground-to-air communications . relatively insensitive to discrete shunt loading of the trolley wire. The typical - Fabricated and tested full-scale MF frequency of operation is about 100 kHz , antenna . and the effects of shunt loading have been analyzed by an approximate transmission - Designed and tested electrically small line analysis. Both the analysis and ex MF dipole antenna and provided receive periments performed by the Bureau of Mines only active antenna for onsite measure confirm that the dedicated wire extends ments from 10 kHz to 50 MHz. the range of transmission . 97 Figure 3-23. Interior view of onsite antenna measurement van capable of providing power gain versus azimuth and elevation angle over a frequency range from MF to X-band. Figure 3-24 . Buried MF antenna power gain relative to that of a short , vertical dipole versus azimuth--13 deg elevation angle . 98 In order to bring together workers in vari Due to the strategic location of the com ous areas of subsurface propagation , ITS mun ication station and the need for im organized and hosted a workshop on EM provement of the physical plant , ITS �as Guided Waves in Mine Environments , March requested to undertake a study of the 28-30. Some of the topics discussed were antenna siting at the communication sta ELF propagation through the earth , MF pro tion . The study was begun last fiscal pagation in coal seams , HF propagation on year . An unpublished report was prepared leaky feeders , and UHF propagation in tha t addressed the question of both MF and empty tunnels . Numerous · foreign countries HF propagation to various regions of the were represented , and a conference pro Northern Pacific/Alaskan region consider ceedings has been published . ing the location of the communication sta tion with regards to the ocean areas and A related topic in mine safety involves the topography of Kodiak Island . Surface nondestructive testing of mine hoist ropes . wave propagation predictions were made for A review of electromagnetic methods for the MF frequencies and were described in nondestructive testing of steel wire ropes last year 's ITS Annual Report. was conducted , and the theoretical limita tions of such methods have been studied . Skywave propagation predictions were made The past theory has been highly idealized for the HF frequencies , considering the and generally restricted to two dimension ocean regions of interest and a set of al analyses . More realistic three dimen seasonal, diurnal , and solar activity con sional rope flaws and both solenoid and ditions . One output of these predictions toroidal rope excitation have been ana is a histogram of the optimum frequency lyzed . The difficult problem of charac use . In addition , the associated distri terizing the anisotropic properties of an butions of take-off angle for each fre actual stranded rope has also been address quency were computed . The frequency use ed . histogram is shown in Figure 3-25 and the set of associated take off angle distri Future work on mine communications will butions is shown in Figure 3-26. These continue . An important problem is propa particular figures include the effects of gation from a tunnel into cross cuts . Also all the seasonal , diurnal , and solar activ the transmission of signals along metal ity conditions; however histograms and drill rods and the input power require distributions were also developed for the ments will be studied . Coupling of radio subset of seasonal , diurnal , and solar signals to blasting cap circuits continues activity conditions . to be a safety problem which requires further study . Work will also continue on Predictions such as those just described the non-destructive testing of mine hoist are used in determining the parameters ropes. The goal is to determine optimum required of the antenna system. The great excitation and sensing configurations . es t problem at the Kodiak transmitter site is the local topography . The horizon ele Kodiak Site Study . The U. S. Coast Guard vation angle as observed from the center communication station Kodiak is located on of the Buskin Table site can be as high as Kodiak Island , Alaska , and due to its loca 12° . tion is very critical to nautical communi cations in the northern Pacific and the A site survey was made to determine the Alaskan region . The responsibilities of station operations and to view the topo communication station Kodiak currently in graphic situation . ITS has reviewed the clude : communication to/from all Coast predicted data, the existing physical plant , Guard vessels in the Northern Pacific/ and topography and made recommendations Alaskan region including aircraft on all to optimize the antenna types and siting routine and emergency missions , reports for best communication . from foreign fishing vessels regarding location and catch within the 200-mile 3.5.2. Transmission Through the limit , continuous guard on several MF and Atmosphere : Applications HF distress and calling frequencies , con tinuous monitor of the AMVER (Automated DOE SECOM Technical Support. This program Merchant Vessel Reporting) system, and supports the ERDA Materiel Tr ansportation assorted other duties as needed such as SAFEGUARDS programs with the major thrust phone patches, land lines , etc . concerning systems engineering support to the functional enhancement and evaluation The proj ected future operational require of the capabilities of the existing SECOM ments for communication station Kodiak communications system . The program was indicate a greatly increased level of initiated in FY 76, and concerned the activity due to a variety of factors . development and implementation of an im Some of . these factors are increased oil proved HF propagation model, mobile antenna exploration and tanker traffic , an in evaluation , and the initial designs of a crease in the number of Coast Guard patrol system management model . vessels and aircraft in the Alaskan re gion , a possible 200-mile pollution con 'I'he propagation model is a modified ver trol , and others. sion of a newly developed HF model inc lud- 99 OVERALL F 1.0 R (._� . 9 E Q 0.8 u 0.7 E ti 0.6 c: 0.5 y 0.4 u 5 0.3 A G 0.2 E 0. 1 0.0 4.0 6.0 8.0 16 .0 22 .0 12.0 FREQUENCY CMHZ ) Figure 3-25 . Overall frequency usage histogram . 1 00 FREQUENCY . 4.0 MHZ FREQUENCY . 6.0 MHZ <3.250 .1'\ . 250 A A N 0.d25 N 0.o<25 ·� ·�· 0.C:00 t. L " . "''"" E E 0.175 0.175 D 0.150 D 0.150 I t 5 0.125 5 0. 125 T T 0.100 R R 0.100 I 0.075 I 0.075 B B u 0.050 u 0.050 T T 0.025 I I 0.025 0 0 N 0.000 N 0.000 20 30 40 50 0 10 0 10 20 30 40 50 TAKEOFF ANGLE "REQUENCY 8.0 MHZ . FREQUENCY . 12.0 MHZ 0.250 �-� .25\."'l -- A A N lt't• .::!l"1"'- " TOT . 154 1 • ,:-, l1 .,��� : L e.c�� L '-'� ·21JI() E 0.175 E 0. 175 D 0.150 D 0 150 I I . 5 0.125 5 0. 125 T T R 0. 100 R 0. 100 I 0.075 I 0.075 B B u -0.050 u 0, .050 T T 0.025 I I 0.025 0 0 N 0.000 tl 10 20 30 40 50 0 10 20 30 40 50 TAKEOFF ANGLE CDEG> TAKEOFF ANGLE CDEG> FREQUENCY • 16.0 MHZ FREQUENCY • 22 .0 MHZ �.25ft.") H 0 . 2Sl) --r------786 . .. " TOT • "·"'"''"'-i , . \'_, ._-·c:L L �t.t .c.\..'V !(..t .c;.l(.llr,) E L €\.175 E D 0.150 D 0. 150 I I 0.125 5 0. 125 T s T 0.100 R R 0. 100 I 0.075 I 0.075 B B u 0.050 T u 0.050 T I 0.025 I 0.02S 0 0 0.000 N II 0.000 50 0 ,) 10 20 30 40 50 TAKEOFF ANGLE CDEG > TAKEOFF ANGLE CDEG > Figure 3-26 . Overall ·take-off angle distributions . 1 01 ing a definition of mu ltipath modes and and telecommunication systems . The results temporal variations of ionospheric para of the study undertaken in support of thi s me ters that would be useful to predict project indicated that significant effects error rates in digital transmission . to the ionosphere and telecommunication This model is installed on the SANDIA Cor systems associated with SPS operation poration computer facility . DoE applica could give rise to ionospheric heating and tions include SECOM mission planning to the high energies associated wi th the SPS assist in frequency selection and communi power beam could result in significant in cations facility schedul ing to maximize terference to a number of telecommun ication probabilities of communications systems users . performance . Real time support applica tions are also intended to assist in iden As a result of the preliminary study con tifying unanticipated propagation-related ducted by ITS , the Department of Energy problems and to provide guidance in con implemented a detailed technical program trol functions for the SECOM system , par of research and development aimed at estab ticularly in frequency selection and site lishing the environmental impact of SPS antenna and processing control actions . operation . ITS has program management Future applications will also involve responsibility for the Ionospheric Modifi multiple parametric software control fea cation aspects of SPS . This work is car tures and signal discrimination where ried out under the SPS Ionospheric Modifi intentional or unintentional interference cation Project . events could occur . The Solar Power Satellite is envisioned to The management model concerns primarily an operate at a frequency of 2.45 GHz supply organization of the operational and func ing between 5 to 10 GW of power to a ground tional timelines for the transport opera receiver site . The system concept utilizes tions , intraconvoy communications , and a satellite in geosynchronous orbits that SECOM system. This provided identification converts solar radiant energy to microwave of normal , unintentional accident , and energy . This microwave energy is trans phys ical threat circumstances with appro mitted from the satellite to a ground sta priate events identified and communications tion and then is converted in de power support linkages . and passed through a power grid . The emphasis in the management model con The large amounts of energy involved can cerns the development of the programs and give rise to significant ionospheric heat supporting routines for the transport opera ing and subsequent modification. As part tions and the linkages to the communica of the support ITS is providing to DoE , a tions event models . Communications models committee of nationally prominent experts include VHF and the HF propagation modes , has been formed (under ITS chairmanship) and system scoring models for the relay to develop a nationally oriented program site and vehicle equipments . The scoring devoted to assess the impact of the SPS process develops the patterns of digital operation on the ionosphere and telecommu errors with relation to the address , veri nications users whose systems are impacted ficat ion/authentication, and data compo by the ionosphere. It is anticipated that nents . This segmentation is necessary to the ITS operated Platteville Heater Facil allow direct coupling to the operations ity will be utilized to simulate SPS heat event model and , in the case of a physical ing effects . Work is being undertaken to threat situation , develop communications define the characteristics of the heater performance relationships for support facility in order to assure that the energy forces and units that protect the trans levels employed in ground-based simulations port vehicles . of SPS operation are commensurate with SPS power levels. Since the communications support to the transport vehicles must include the multi ITS is also working in conjunction with convoy communications operations, the NOAA and NCAR to develop realistic , accu event and technical characteristic models rate numerical models of the ionosphere for the VHF systems have also been design and its variations under conditions of in ed . This system has only voice mode with tense ionospheric heating. These mode ls little protection from external deception are used in conjunction with telecommun i or interference. Different mo des of opera cations ' system simulation programs to tion including relay configurations have determine , from a theoretical viewpoint, been examined , and recommendations sub SPS impact on the performance of selected mitted indicating reliability advantages radio circuits. for different options in procedure and configuration . The basic management model SPS HI Q Study . The question was raised organization is diagrammed in Figure 3 - 27 . as-to-whether local free space field strength maxima (hot spots) inside habit The SPS EMC Assessment Project has as its able structures exposed to 2.45 GHz SPS obj ective a preliminary assessment of the radiation can exceed the uniform power den impact of operation of a Solar Power Satel sity of the incident traveling SPS coherent lite (SPS) on the ionosphere , atmo sphere , plane wave radiation . 102 CONVOY MOVEMENT EVENTS • ROUTE PUBLIC INTERACTION EVENTS • INTRUSION FORCE INTERACTION EVENTS • • COMMUNICATIONS INITIATION MEDIA EFFECTS SOF TWARE SITUATION RESPONSE RECEPTION/ PROCESSING II----_. DECISION IIJ---+ ANALYSIS/ RESPONSE FORCE SCORING 11---_.1 LOGIC/COMMANDS DECISIONS ACTIONS Figure 3-27. Management mode l organization . 103 The answer lies in the assessment of two SSPS direct power coupling, and ionosphere electromagnetic effects : and atmosphere media modification effects . Primary evaluation areas include EM envi 1. Coupl ing and penetration of field ronment verification computations , coupling energy into an enc losure . analysis, functional-operational priority categorization , degradation evaluations , 2. Storage of field energy in the in and impact assessment. Subsequent tasks terior space . address mitigation methods for degraded sy stems , and guidelines for designers and To model the problem , habitable structures planners of future systems which may have were categorized by means of the enclosure to operate in a SPS environment . material as shown in Table 3-2 . Information was obtained from NASA on SPS The question was investigated using mode system definition including: single micro and field theory . The conclusion was that , wave power transmission system radiation though habitable space presents a poorly characteristics; geostationary earth orbit defined problem electromagnetically , field locations for multi- satellite operation; hot spots are very unlikely . The probabil emission power spectra; side lobe struc ity of a microwave hot spot occurring in ture , and candidate rectenna sites . A side a habitable structure is probably not mo del is being implemented to predict field higher than that of a focal point for sun strength footprints at and near the sur radiation occurring in nature with the face of the earth from SPS microwave emis potential of starting a fire . This find sions . Priority rectenna sites are being ing is confirmed by the results of exten analyzed from the candidates identified sive measurements made by ITS of the 2.57 by NASA and DoE . Equipments and systems GHz signal from the ATS-6 geostationary near the rectenna sites that are suscepti satellite inside many single family dwell ble to SPS radiation are identified by ings across the continental U. S. These selective retrieval from existing files , measurements yielded average insertion and categorized in relation to function , losses (inside-to-outside field strengths ) coupling modes, location , and interconnec between 6 and 9 dB . tivity . Functional degradation because of the SPS interference magnitudes include A summary entitled "Field maxima inside all performance events required to define habitable strucutres exposed to 2.45 GH z supported operational compromises . Scoring SPS radiation" was prepared . Measures to models (signal/interference ratios) are mitigate potential field hot spots are pro multidimensional to allow adequate defini posed . A more detailed technical report tion of the operational relationships. with over 30 references is being prepared These are demonstrated in the functional to back up the preliminary findings out degradation summaries presented in Table lined in the summary . 3-3. SI scoring models are being designed for victim systems , and tests will be de Solar Power Satellite EMC Analysis . The signed and implemented on candidate systems Department of Energy 's Office of Energy where data vo ids exist. Re search has tasked ITS to assess the po tential RFI/EMI effects of a proposed The impact of SPS EM energy on "victim" Solar Power Satellite (SPS ) System. These systems outside the rectenna area will satellites would use photo-voltiac cells come mainly from power beam side lobes , to transform solar energy into DC vo ltage emission of harmonics of the primary fre which would drive high power microwave quency and spurious components , noise sources to produce a high energy microwave sidebands, and terrain reflections. Other beam at 2.45 GHz aimed at the earth . The sources of EM energy in the surrounding beam would be received at a rectifying area of the rectenna would come from iono antenna site (rectenna) some 100 km2 in spheric and atmospheric effects such as area . The distribution of power across scatter out of the power beam by rain. the beam is gausian with a power density Ionospheric and atmospheric effects are at the center of 23 mW/cm2 and at the edge now under study , but the main program in of the rectenna 1 mW/cm2 • The total elec this area will be accomplished in FY 79. trical energy output at the rectenna site is calculated to be around 5000 megawatts . Energy coupling to victim systems will involve in-channel and non-linear responses Because of the large powers involved the by out-of-band components relative to the potential EMC problem is recognized as one primary receiver pass band . Different of the most critical in the SPS assessment . scoring procedures are required because of Consequently , an agressive program has the wide variations in the latter in the been initiated to perform analysis of the characteristics of energy coupling and the functional and operational degradation of intermodulation of components of the inter electromagnetic systems (communications , ferer with the desired signal . Scoring radars , navigation aids) and other environ procedures applicable to this problem can ment sensitive equipments and systems be derived by extrapolation of existing (computers, sensors , electronic medical empirical and analytical degradation models instruments and devices, etc. ) because of for receiver systems employed for communi- 104 Table 3 - 2. Categories of Habitable Structures CASE MICROWAVE PROPERTIES REAL STRUCTURE EQUIVALENT l lossy dielectric brick , stone , frame house 2 composite of lossy dielectric trailers , house with metal and metal siding , plant building 3 metal with lossy dielectric aircraft cabin, vehicle layer plus aperture interior All geometric dimensions are generally much larger than one half-wavelength (6 em) . Table 3 - 3. Selected Site Distances from Mo j ave Rectenna Distance From SPS F ield Rectenna Intensity ( 2. 45 GH z) SPS - China Lake Airstrip 64 km 1.3 v/m SPS - Downtown Barstow 51 km 1.8 v/m SPS - Edwards AFB Airstrip 43 km 2 v/m SPS - Restricted Area R 2524 53 krn 1.6 v/m SPS - George AFB Airstrip 61 km 1.4 v/m 105 cations , radar , or a general range of power beam side lobe energy , could present me tering applications . These define a a formidable problem for systems out to range of performance characteristics in 100 km or so from the rectenna site . terms of probability density functions for signal to interference ratios . Mo st of To assess the impact on systems near the the EMC problems related to the SPS that Mojave site , an area 145 km by 145 km with represent a significant expenditure in the proposed rectenna site at the center victim equipment modification will be con was chosen as our data sample area. All cerned with the non-linear response cate government and non-government EM systems gory . operating within this geograph ic boundary between 75 MH z and 5 GHz were tabulated . Computer devices , optical equipment , and The active files showed 813 government medical instrumentation present unique systems and 685 civilian authorizations scoring descriptives that relate to effec operational within these boundaries . tive apertures and energy coupling into signal and control circuitry . These types The equipment/system categories identified of problems can, to a less degree , be extra in the file retrieval are as listed : polated from experience with high-power radar illumination of surveillance and 1. Military Development and Operational monitoring equipment required for military Test and Evaluation Support operations . Limited measurements will be required for the SPS problem to assure 2. Industrial Communications credibility in the pred icted degradation and recommended functional modifications 3. Transportation Support Systems for these classes of equipment. 4. Public Service Communications As the SPS program advanced and the concept appeared to be an obtainable goal and a 5. Specialized Services . viable alternative to the pressing energy needs of the future , candidate rectenna These system categories are in the fre sites across the continental United States quency range cited for the file retrieval (CONUS ) were identified by a NASA study . and are susceptible to SPS power densities Subsequent coordination with the NASA/MSFC previously displayed . Advanced Planning Office indicated an ac tive study emphasizing a Mojave desert The character of functional degradation rectenna site . The initial EMC analysis induced into particular ma jor equipment exerc ise addressed this site to provide categories deployed near the candidate EM impact data to this site characteristic Mojave site is indicated in Table 3-4 . review , and contribute to the development Those functional systems included repre of site selection criteria for NASA/DoE . sent high priority operations that encom pass relatively large geographic areas Figure 3-28 shows the Mojave site and the around the periphery of the rectenna site . surrounding area which would be impacted by SPS emissions outside the rectenna Various railroad , law enforcement , and enclosure . emergency communications services will be incorporated into the functional categories The rectenna site is shown (shaded area) as soon as degradation analysis is com with center at 35° 8' North , 117° 30 ' West. pleted . These equipments use presently The rectenna covers an area roughly 100 VHF and UHF analog voice or low data rate km 2 • The outer elipse is roughly 49 km modes , and will therefore be minimally in radius and corresponds to the peak of affected . Relays and base stations for the lOth side lobe , and is approximately these services could be readily modified 45 dB below main beam peak power . where necessary by shielding and antenna pattern adjustments. Common carrier links Preliminary assessments have been made at wi ll also be scored for future assessment five sites surrounding the Moj ave rectenna analysis . These will include relays and site . Those sites , their distance from mode stations . the rectenna , and the expected field in tensity of the SPS 2.45 GHz power beam The elements of performance degradation frequency at the respective sites is given cited for the functional systems represent in Table 3-3. Added to this intensity due an average over all operating modes and - on ly to--beam configuration would be energy geographic range . For example, instrumen scattered from the power beam by media tation radar systems detection and track effects such as rain , hail , dust and sand ing performance includes operation over a storms , atmospheric turbulence, etc . This full hemisphere coverage , and the range of could add from 20 to 100 mV/m of scattered cross section magnitudes for military tar energy into the sites depending on the get vehicles (e.g. , tactical fighter and severity of a given storm . The amount of reconnaissance aircraft, target drones ). potential EM energy from all forms of Track score variations include low eleva scatter , including that from the rectenna tion angle modes , where the accuracy de itself (not calculated yet) , added to the gradation and loss of lock probabilities 106 N 1 IIP30 Figure 3-28 . Proposed Mo j ave rectenna site . 107 Table 3-4 . Induced Functional Degradation Summary - Moj ave Area FUNCTION CHARACTERISTIC EFFECT Instrumentation Radar a. Cooperative target acquisition (Military Test Ranges) range: -8 to 20% b. Skin target acquisition range : -13 to 28% c. Cooperative target track error : +15 to 40% d. Skin target track error : +22 to 65% e. Loss of track loop lock (skin mode ) probability increase : +10 to 40% Command/Control and a. Signal acquisition threshold: Telemetry Communications +5 to 20% (Military Test Ranges ) b. Data error : +5 to 28% c. Sync loss probability: +3 to 25% Tactical Signa l Identification - a. False alarm probability outside Analysis Systems mission zone : +3 to 25% b. False alarm probability within mission zone : +18 to 60% c. Receiver noise threshold: +5 to 40% d. Signal processing time : +45 to 115% e. Software overload probability increase : +2 to 26% ------·------ IR Scanner (Tactical System) a. Video noise threshold: +2 to 26% b. Target detecti on/identification probability: -5 to 33% Ut ility and Pipeline a. Signal acquisition theshold : Command/Control/Telemetry -5 to 15% Communications b. Data error : +10 to 30% c. Link noi se: +5 to 20% Image Intensifiers a. Video noise level: +10 to 45% b. Standard target detection/ identification range : -5 to 30% c. Mu ltiple target spatial resolution : -2 to 60% Non-Federal Government a. Channel noise: +5 to 15% C ommunications b. Data error : +8 to 35% 108 expand by greater margins because of pro of the data retrieval and analysis pro pagation factors . On-axis radar configu cedures required for the EMC analysis of rations are also represented since this all candidate CONUS sites . This Mo jave mode will probably be increasingly employ site originally considered by NASA allowed ed for these test range applications . The a reasonable rectenna isolation from areas track error scores include normal smooth of even mo dest population density, but pre ing , prediction filtering, and coordinate sents serious interference impacts upon computations in real time and postmission surface and aircraft electronic systems . processing software . At this site , military operations repre sent the ma jority of the interference prob The communications system degradation lems , the degraded systems being integral cited include single channel, and frequency components of complex Development and and time-multiplexed units operated by the Operational Test and Evaluation programs . mi l itary test ranges , the State of Cali These mi litary programs require the degree fornia, local county and municipal govern of isolation afforded by the Mo jave region . ments , and resource control and service industries. Based on the probable operational system degradations near the Moj ave site and the These operational compromises and the spe inability to establish mitigating strate cific areas of functional degradation will gies without unacceptable probability of be expanded to provide the basis for sub operational compromise , a second site sequent recommendations in equipment and north and east of the original site was system operations to assure an acceptable proposed by ITS . A cursory look at the level of performance when illuminated by "victim" systems surrounding the new site this high power source. indicates different functional classes which lend themselves to mitigating strate For this Moj ave site and others having a gies . Modifications to most of these similar operational military/civil system equipments could be accomplished to produce ratio, modification recommendations will compatibility in the SPS generated environ emphasize the civilian area . Support ments . equipment (e.g. , radars , telemetry , TV , etc.) can be modified for operation within The functional degradation of military , a range of 40-50 km from the rectenna site, non-defense government , and commercial assuming no media induced instabilities in systems in the Mojave area is basically the SPS array control . Military operation characteristic of the effects that will be al EM systems cannot be modified because encoun tered in other CONUS areas . Opera of the unacceptable probability of opera tional implications and therefore the tional compromise; system performance or associated economic impact will vary signi procedures in the Test and Evaluation ex ficantly because of the differing organi ercises would have little or a deceptive zations and systems supported by the de relation to combat operations . graded equipments . Operational-functional relationships will exhibit differing sensi Much of the major work of this present tivities . program will be accomplished in FY 79 in cluding the development of mitigating The Mo jave area lends itself well to re strategies that would allow mo st classes siting because of the large expanse of of systems to operate satisfactorily in open , flat terrain. The development of an SPS induced EM environment . new sites in mo st geographic areas would not be as simple , if not impossible , due The preliminary assessment of SPS micro to population density , terrain features , wave emissions on "victim" systems as given "victim" system density , etc . here demonstrate the operational degrada tion that would occur to electronic sys Generally the northern and eastern CONUS tems in the SPS generated environment with regions will have a smaller mi litary-non in approximately 100 km of the rectenna defense equipment concentration in the site . The Mo j ave site evaluation shows a rectenna areas than the original Mo jave wide range of performance degradation , site reviewed . These regions will also particularly in those systems operated by include ma jor transportation and comme r the military . The basic functional and cial communications facilities . Because operational impacts of SPS are of such of the population and business densities , magnitude that in many instances they re the total number of affected systems in present unacceptable or impossible compro the various operational categories will mises and biases to proper test and evalua be larger . tion exercises performed by the involved facilities . A valid demonstration of rectenna site EMC analys is and impact evaluation has been As mentioned previously , the evaluation of developed . This has shown to be fundamen the Mojave candidate rectenna site provided tal in making site selections , will help impact data to NASA and contributed to determine system performance impacts , and establishing site selection and evaluation help develop mitigating strategies for criteria , and allowed a limited exercise victim systems . Several site evaluations 109 in various geographical locations , parti directly in the time domain, and at a data cularly in northern and eastern CONUS re rate that can be conveniently recorded on gions wi ll be carried out to establish a analog magnetic tape . The primary data data base to be used in setting site selec from this phase of the measureme nts uses tion criteria and geographically oriented a clock rate of 150 Mb/s , providing a mitigating strategies . total resolution of approximately 6 ns in the impulse response . However, delayed RADC Consulting . The U. S. Air Force is components less than this va lue are easily developing digital commun ication equipment distinguished in the output. The same bit for application to tropospheric scatter stream is detected from the hi-phase mod radio systems in Europe . This project is ulated signal , and fed to a commercial a consulting and advisory effort to assist error analyzer for the second phase above . the Air Force in testing and evaluating In this case , the clock rate of the system the communications equipment , and its per was reduced to either 10 Mb/ s or 50 Mb/s ; formance over the proposed links . The rates that are more commensurate with the work is performed as requested by RADC , desired data rate for the proposed PMTC and involves a broad spectrum of expertise sys tem . However , the resolution of the from the ITS staff. impulse response is less at the lower clock rates . Therefore , mo st of the data Microwave Propagation for Digital Radio . were measured in tandem blocks . The high The U. s. Navy Pacific Missile Test Center clock rate was first used to observe chan (PMTC ) at Pt. Mugu , California operates a nel conditions for a period of time , the network of microwave and other communica clock rate was then reduced to obtain a tion systems in support of the test center me asure of BER performance under the vary missions. Future plans for the microwave ing conditions . system include conversion to all digital transmission . However , some of the links Measurements we re begun in August 1978 to are over-water paths extending from high capture the worst propagation conditions locations along the coast to terminals in that have historically prevailed during the Channel Islands . that month . The measurements will not be completed until early in the calendar year From past experience , it is known that 1979. Preliminary analyses of the August severe propagation conditions exist in the data indicate that the strong surface ducts Pt. Mugu region. These conditions are in the region give rise to very severe primarily caused by meteqrological factors multipath propagation as well as flat pow such as deep refractive layers with very er fading . Delays of up to 20 ns have high negative gradients . These layers been observed in the impulse data for the develop due to a high marine layer of air multipath components . In addition , it is at the coast line . The propagation is frequently found that the delayed compo characterized by deep signal fading, caused nent is of much greater magnitude . The by a mixture of power fading and multipath time variability is also a significant signals. In order to determine the digi factor , as the stronger component both tal data rate that these circuits will leads and lags in the response . Changes support under such conditions , the ITS was of this type cause synchronizing problems tasked by the PMTC to conduct some experi in digital systems . It appears that space ments over a link between Laguna Peak and diversity is effective mo st of the time . San Nicholas Island , a distance of approxi However , there are occasions when the mately 65 miles over water . The experiment mu ltipath structure is observed on the consisted of three measurements as follows : spaced receiving antennas almost simulta neously . Data from the tilted beam experi 1. The impulse response of the transmis ment have not been analyzed as yet . These sion channel. results wi ll be published in a final report in FY 79 . An example of the impulse re 2. Bit-error-rate (BER) performance mea sponse during a short period of strong surements . multipath is shown in Figure 3-29, which presents a sequence of responses measured 3. Fading statistics on a pair of re 100 ms apart . ceiving antennas oriented for angle diversity. 3.5.3. CCIR Participation The first two measurements were performed Support to the International Telecommuni using the ITS pseudo-random noise (PN) cations Union 's (ITU) advisory Interna probe (R. F. Linfield , R. W. Hubbard , and tional Radio Consultative Committee (CCIR) L. E. Pratt, "Transmission Channel Charac was provided by ITS personnel in the fields terization by Impulse Response Measure of tropospheric (Study Group 5) and iono ments ," OT Report 76- 96, 1976) . The bi spheric (Study Group 6) propagation . The nary bit stream used as the test signal in U. S. National Chairmen of CCIR Study this instrument is correlated with a rep Groups 5 and 6, Drs . H. T. Dougherty and lica signal at the receiver to develop C. M. Rush, are both members of ITS's the impulse response . This output of the Applied Electromagnetic Science Division . receiver indicates multipath reception 110 Figure 3-29. An example of mul tipath observed in the impulse response measured over a long over-water LOS microwave path . The sequence progresses from top to bottom in time , at 100 ms intervals . The delay time scale is 10 ns/cm . The response shows a two-path propagation mode with a delay of approximately 8 to 10 ns . 111 In addition , numerous ITS personnel ac tive ly participate in the CCIR. For example, at the Final Meeting of Study Group 6 held at Geneva in January 1978, there were four (4) ITS staff personnel as members of the U. s. delegation (which totaled 9) . Areas of specific concern to CCIR in which ITS personnel play key roles include : ionospheric mapping ; ionospheric operation al considerations; skywave field strength calculations at frequencies above 1.6 MH z; microwave system design ; fading phenomenon on LOS links ; the role of rainfall in microwave system performance and interfer ence ; and the ionospheric and tropospheric aspects of radio noise . ITS personnel participated in the Inter national Telecommunications Union (ITU) Advisory International Radio Consultative Committee (CCIR) XIV Plenary Assemb ly that was held at Kyoto , Japan , in June 1978. Figure 3-30 is a photograph of part of the U. S. delegation to that meeting. In addition , ITS personnel have been parti cularly active in the preparations for the CCIR Special Preparatory Meeting (SPM) scheduled for Geneva in October and Nov ember 1978. These preparations included the assembly of U. S. documents as inputs to the SPM and the review of input docu ments provided by other nations . The ob jective of the SPM is a report to the General World Administrative Radio Con ference (GWARC-79) to be held in Geneva in 1979. The ITS-supported efforts serve the obj ective of preparing a receptive atmosphere for adoption by the SPM of u. s.-supported quantitative technical assistance for the use of the policy makers of the ITU . 112 Figure 3-30 . A portion of the U.S. delegation to the CCIR XIV Plenary Assembly , which included four of the NTIA/ITS staff. 113 ANNEX I ITS PROJECTS FOR FY 78 ORGANIZED BY DEPARTMENT AND AGENCY Title Leader Title Leader AGRICULTURE , DEPARTMENT OF DEFENSE, DEPARTMENT OF (DOD) (Continuecl) 9103483 FIRESCOPE Communications Sys Air Force Space & Missile Sys tem (SAMSO) tem Design "lorrison 9101463 Buried Antenna Studies - MX Phase II FitzGerrell COMMERCE , DEPARTMENT OF (DOC) 9103502 Propagation Path Loss Measure - ment Haakinson National Telecommunications and Information 9103503 Application of PROGAAM WAGNER Ott Admin1strat1on (NTIA) Air Force 0iscellaneous 9101076 TSC Standard Wo rking Group Support Hurray 9103441 MSR-Tl Mul tiple Receiver Barghausen 9102085 Analysis & Development 9103486 Propagation Over Irregular Support Haakinson Terrain Ott 9103095 RSMS Development �lathe son 9103492 TAC -Signal Analysis System Barghausen 9103096 RS�!S Operations �Ia the son 9103493 Power Fading Statistics Hufford 9105098 Special Proj ect �lcManamon 9107262 Urban Propagation Model Hufford Naval Research Laboratory (NRL) 9108111 A�l Stereo deHaas 9108200 EM Wave Transmission M&S Lucas 9102370 Proj ect NONESUCH Tveten 9108201 Frequency Extension Research ,. Thompson 9103508 Navy Optimum Communications Spaulding 9108202 Frequency Reuse Research Dougherty 9108203 Scattering Effect/Inform Pacific 'li ssile Range (PMR) Bandwidth Ott 9108204 Satellite Scintillation Hodel/ 9103497 Ground/Air Propagation 19 & 28 GHz Ott Predictions Gierhart 9108206 "'W Trans/Trope Ducts Wait 9103543 PMR Microwave Link Tests Hubbard 9108207 Propagation l!odels f1 Data Base Rush 9108208 VHF/UHF Urban/Rural Model Hufford Navy Miscellaneous 9108209 Satellite Observance at 19 & 28 GHz Grant 9103515 Calibration of Water Vapor 9108221 Data Communications Seitz Measurements Thompson 9108222 Optical Commun ications Bloom 9103553 Atmospheric f.HF Propagation 9108226 EMS Technical Planning Hull Study Liebe 9108232 Trade-offs in Spectrum Use Berry 9108234 Needs Study Hurray Army Research Office (ARO) 9108237 Spread Spectrum Interference Plan rturray 9103550 DM-4/Calculator Software Paulson 9108250 Direct Satellite Communication �1c�1anamon Army Communication Command (USA/CC) :>iaritime Administration UIARAD) 9103382 Army Mob ile Automatic Receiver 9102419 MAR.A.D Assistance de Haas System Carroll 9103427 I'MC Van , Part II Carroll National Bureau of Standards (NBS) 9103434 Access Area Digital Switch Program Nesenbergs 9103551 IACP/NBS Test Program Bolton 9103446 Applications Software McLean 9103447 CEEIA Fiber Op tics Handbook Hubbard National Oceanic & Atmosph eric Administration (NOAA) 9103452 EMC Data Recording System llarr 9103463 Operation Sky-Wave Rush 9103412 Propagation Consulting Dougherty 9103465 EMC Cosite Analysis Capability Adams 9103417 Weather Radar RFI Surveys Tary 9103470 EMC Remote Extension Diede 9103506 Engineering Support Wortendyke 9103474 Automated Digital Topographic 9103535 SPS Hi Q Study Liebe Data Techniques Spies 9103536 SPS RFI/EMI Analysis Grant 9103478 H!C Van , Part III Carroll 9103537 SPS Ionospheric Modification Rush 9103491 Follow-on Maintenance Stewart 910 34 9 9 \' ideo Tapes on TAEHS Tary 9103501 Application Enhancements Stewart DEFENSE , DEPARHIENT OF (DOD) 9103504 Automated Digital System Eng- ineering �lodels fiause Air Force Communications System (AFCS) 9103505 Automated Field Instnsity Measurement Syste� Haakinson 9103484 Automatic �!easurement System 9103507 TAEMS Noise Measurements Spaulding Upgrade Wortendyke 9103509 Topographic Files Hufford 91035ll Voltage Tuned Pilter Carroll Air Force Systems Command (AFAL) 9103513 TAEMS Repair Parts Stewart 9103514 Non-Tactical Radio Networks Hubbard 9103530 RADC Technical Support Hubbard 9103531 ADRES System Upgrade Harr 9103532 Multipath Fading on Long Air Force Systems Command (ESD) LOS 15 GHz Paths Hause 9103533 Aircraft Blockage Effects on 9103479 EFAS/PEP II Program Skerj anec Microwave Links Traversing 9103528 HF Ionospheric Scattering Runways & Taxiways Skerj anec Study Violette 9103534 Channel Probe Measurement/MW Links Hubbard 9103538 Verification Test Set Smith 9103546 TCN Related Services Lucas 9103547 Digital System Performance Verification McQuate 115 Title Leader ______:: Ti tl _;_c _____ Leader DEFENSE , DEPARTMENT OF (DOD) (Continued) NATI ONAL AERONAUTICS f, SPACE AmiF\ISTRAT ION (.\i\ SA) Army Miscellaneous 9103494 Orbiting Standards Platform Analysis llougherty 9103498 Long Distance Propagation Study Lloyd 9103525 Spectrum Monitoring Unit Adams 9103527 Frequency Dxtension of Spectrum OFFICE OF TELECOMMUNICATIO:\S POLICY (OTP) Monitoring Capab ility Adams 9103544 Microwave Intervisibility Prop 9108520 RSMS Deve l opment �:a the son agation Loss Measurements - 9108521 RS�IS Operations �.tn thcson Division 1 llaakinson 9108522 Snectrum A11alvs is Stlpport !Iaal,inson S 9103545 Microwave Intervisibility Prop - 9108524 T C Support · 'ftn· ray agation Loss ;\,1easurements - 9108527 SED Propagation neveloproent l !ufforcl Division 3 Thompson 9103555 30-300 Gllz Communication Links Thompson TRANSPORTATION, DEPARTI��T Of (DoT) Defense Communications Agency (DCA) Federal �\"i.ation Mm1ni_:;_t:ra tion J.I:_c\A) 9101534 1-!EECN Simulation l'iatterson 9103512 Glossary Update Hanson 9101477 Air Navigation �ids Jobnson 9103489 Technical Support in Propaga National Security Agency (NSA) tion & Spectrum r: nr,ineering Jiul"harc! 9103500 A1r Traffic Control Services llartr.:on 9101518 NSA Consulting Spaulding 9103521i Air �avigation �ids Johnson 9103549 0!usketeer Freda V. Ste·h·art , A. 9103552 Topside Noise Morphology Rush U.S. Coast Guard (USCG� 9101532 Consulting L' SCG Kissick ENERGY RESEARCH & DEVELOPMENT ADMINISTRATION (ERDA) 9103488 KODIAK An tenna Improvement Kissid 9103548 San Juon/ADAK Trade-off I( i. s s j ck 9103450 SECOM Management Mo de l Rush 9103554 FAA Propagation �tudy Rush 9103523 SPS EMC As sessment Rush ll .S. POSTAL SERVICf: FEDERAL CO�Jlc!UNICATIONS COMmSSION (FCC) 9103432 l' .S.P.S. Electronic "essage Service 'fc�· ianaron 9103510 Sharing of Broadcast Radio 9103529 U.S.P.S. Elec tronic \!cssare location Services deHaas Service 01c�fanaJron 9103516 Spread Spectrum Land Mobile Radio Systems Berry 9103517 Spread Spectrum LMR-TV Sharing Berry OTHER 9103518 Waiting Time Probabilities for LMR Berry 9101583 Lf Hodels Eerry 9103519 Trans lator Service Hufford 9101585 GOES Equipment rertificotion Bolt on 9103520 TV Coverage Maps Hufford 9101586 Tropo Predictions Johnson 9103522 Compatihle SSB for !IF Broad 9101587 Numerical Prediction Services cast, Phase I deHaas PFA ;\py 9103539 CATV/ATC Interference Adams 9102580 Analysis Services !\ ;l ams '!i scellaneous T'ederol J\ renc.ies INTERIOR , DEPARTMENT OF (DOI) 9101504 IIF Consulting 9101453 BO�! Analysis of H! Waves 1'/a i t 9103482 Safeguards Communication Analysis >'orrison INTERNAT I ONAL CO�!li!UNICAT ION AGENCY (ICA) �1iscellaneous �on-Federal Agencies 9101498 Remote Access Computer Service Agy 9102378 �'obile Aids fluffore ! 9101499 Radio Propagation Predictions Agy 9103521 Be ll Consultinr Spaul cl i n g 9101501 Development Improvements of Prediction Formats Agy 9101503 VOA Consulting Haydon 9103524 Revision of HF Broadcast Methods Agy 9103540 VOA Consulting Haydon 9103542 Remote Access Computer Services Agy 116 ANNEX II ORGANIZATI ONAL DIRECTORY INSTITUTE FOR TELECOMMUNICATION SCIENCES NATIONAL TELECOMMUN ICATIONS AND INFORMATION ADMINISTRATION, DEPARTMENT OF COMMERCE 325 Broadway , Boulder , Colorado 80303 (303) 499-1000 (FTS dial 323 + extension) NAME EXT. ROOM DIRECTOR 'S OFFICE (0/D) CROMBIE, Douglass D. (Director) 4215 3020 UTLAUT, \'Ii lliam F. (Deputy Director) 3500 3020 WALTERS , Wi lll am D. (Budget and Accounting Officer) 4414 3019 STONER, Russell B. (Publication and Technical Information Officer) 3572 3009 \'I AIT, .J ames R. (Consultant , also with NOAA and CIRES) 6471 227 (RB 1) WIEDER , Bernard (Assistant to the Director for Program Deve l opment) 3484 3014 DIVISION l - SPECTRUM UT ILIZATION "!URRAY , .John P. (Associate Director) 4162 4533 1.1 Radio Spectrm1 Occupancy �!ATHE SON , Robert .J . 3293 2221 1.2 Antenna Performance F1tzGERRELL, Richard G. 3737 4524D 1.3 E�C Analysis & Deve lopment ADAMS , .Jean E. 4301 4517 1.4 VHF/UHF Models li Mobile Sys tems HUFFORD , George A. 3457 4 52 3 DIVISION 2 - SYSTH!S TECHNOLOGY & STMIDARDS HULL , .Joseph A. (Associate Director) 4136 2034 2.1 Channel Characterization HUBBARD , Robert 1'1. 3414 2243 2.2 New Technol ogy Development BLOOM , Louis R. 3485 224SA 2.3 Systems Engineering & Analysis HULL, .J oseph A. (Act1ng) 4136 2034 2.4 Sys tems Technology deHAAS , Thijs 3728 2030 2.5 Systems Assessment Md!ANAMON , Peter M. 3570 2237 DIVISION 3 - APPLIED ELECTROMAGNETIC SCIENCE LUCAS , Donald L. (Associate Director) 3821 3421 3.1 Spectrum Extension Research & An alysis THOMPSON , �!OODY C. 3508 3442A 3460 3411 3.3 Advanced Communication Technology & Appl ications GRANT , \'illllam B. 3729 3447 3.4 Advanced LUCAS , 3821 3421 117 ANNEX III INSTITUTE FOR TELFCO�rr�NICATION SCIENCES NATI ONAL TELFCONt.IUNICATIONS AND INFORMAT IOK ADHINISTRATI Oi\ DEPARTI!ENT OF C0�1mRCE Alphabetical Listing of ITS Employees September 1, 1978 Name Ext . Room [-! arne L>t . PoOJ'l ADM!S , Jean E. 4301 4517 l!ILL, D8vid 1\ . 347 2 2209 ADAMS , Steven l'' 3513 3442 I'OROI•:ITZ , Renee P. 4 162 -1520 AGY , Vaughn L. 3659 3441 I 10\vARD , � 11 en 0. 3485 2 2 4 5 AKH!A , IIi roshi 3392 2210tr l!UBBARD , Rebert 1•.' . 34 14 2243 ALLEN , Kenneth C. 3513 3442B J!UFFORD , George •\ . 3457 4523 BARGHAUSEN , Al fred F. 3384 3443 !lULL , Joseph A. 41 36 2034 BEASLEY , Ke ith R. 3731 4524A 1\l'NT , Howard ll . 3 778 2213 BEERY , We sley M. 3501 3463 IIYOVi\LT I, Duane I. 3447 34 51 BERRY , Janet S. 4129 4518A BERRY , Leslie A. 4474 4528B JEFFREYS , Charlene f. 4414 )f\:2] JENKINGS , Rnymond D. 32 3 3 452 4 C BLOO�!, Louis R. 3485 2245A JOH)';SON , �18 rv r:llen 3587 4 522(' BOLTON , Earl C. 3104 2236" .J UNFAU , Robert I. 4 202 2222 BROOKS , Minnie 3929 3451 JUROSIIFK , John !\, 4 362 45281\ CANADAY, Lois S. 3634 3417 KHI'II'TT , F. Georfe 3945 2230E CARROLL , John C. 3601 3459 KISSICK, Vi11iam A. 4258 4520C: CIIAVEZ, Richard 3584 3430 CHILTON , Charles J. 3815 3420 COLEMAN , Susan J. 3883 3450 LANGER , Susan K. 4162 4527 LAWRENCE , Vincent S. 4 202 2222 LAYTON , Donalr1 1'. 3584 34 30 COURTNEY , Brenda L. 4162 4530 LIEJJE , Ilans J. 3310 34 2 6 CRO�BIE, Douglass D. 4215 3020 LINFIELD, Robert F. 4243 2�36A CROW, Edwin L. 3452 2210 CURLANDER , John L. 3358 3450 LLOYD , .John L. 3701 3419'1 LONGLEY , Anita G. 3·1 7 0 4521 41 2 5 •1 520A deHAAS , Thij s 3728 20 30 LliBE:i , Robert A. DEL PIZZO, Rose M. 4162 4527 LUCAS , Donald L. 3 8 2 1 34 2 5 DIEDE , Arthur II. 3103 3458B DOUGHERTY , llarold T. 3913 3453 DROUILLARD , Patricia II. 4337 3015 �1ADONNA , {�ancy 3821 3� 21 r!AJOR , Jeanne C. 4122 4520B r1ARLER , F. Gene 3 4 1 2 34 46!3 3293 DUTTON , Evan J. 3646 3454 C MATHESON , Robert J. 2221 HARTIN, William L. 3195 342 4 ESPELAND, Richard H. 3882 3410/1 MAYEDA , Kathy r:. 3998 3420 �IELLECKER, Carlene '1 . 3330 3458A 34 30 FALCON, Glenn D. 4361 2222C l.·!E NDOZA , .John R. 3584 3506 2 2 4 FARROW , Joseph E. 3607 2230 HILES , llartin .T . 6 4496 3454A F itzGERRI'LL , Richard G. 3737 4524D 'liLLER , Charles '' . FRITZ , Ol ive H. 3778 2213 IJ INISTER , Carl hl 3805 2242 3 513 3442 GALLAl'IA , Robert L. 3761 2217 HITZ , Albert P. 3821 3421 GAMAUF , Kenneth J. 3677 3430 )IOLLARD , Jean R. 3291 2219 GEISSINGER , Marcia L. 3500 3020 I'ONTGOHERY , carole .J . 4215 3(113 GIBSON , Beverle J. 4215 3020 MORRISON , Ernest L. GIERHART , Gary D. 3292 2222H HURAHATA , Sueki 3513 3442 4162 4533 GLEN , Donald V. 3893 2210 MURRAY , .John P. 3883 3449 GODWIN, John R. 4302 4515 McCARROLL , Patricia A. 4281 2245 GOULD , Beverly A. 3588 4525 McCOY , Elizabeth L. H6 2 34 6 GRANT , William B. 3729 3447 t.lcLEAN , Robert A. 2 3307 2210B GRAY , Evelyn P. HcHANAHON , Peter II . 3570 2218 3778 2 21 HAAKINSON , Eldon J. 4304 4511 McQUATE , Paul L. 3 HAIDLE , Leroy L. 32 33 4524B HANSEN, Ruth B. 3513 3442C 3337 2210)! HANSON , A. Glenn 4449 2223 NfSENllERGS , Martin 3396 4524A HARMAN , John M. 3655 2030 NFY , Linda 4136 2030 HARR, Thomas A. , Jr . 4191 4518B OLSON , Marylyn N. 3353 346 7 EARn1AN , Wi lliam J. 3606 2210D OTT , Randolph II . IIAUSE , Laurance G. 3945 2230B HAYDON , George W. 3583 3420C HILDEBRANDT, Thomas H. 3175 2230 119 Name Ext . Room Name Ext . Room PAULSON, Sara J. 3874 4519 TARY , John J. 3702 3450 PAYNE , Judd A. 3200 2214A TELFER, Thelma L. 4162 4529 PHILLIPS, Robert E. 4125 4520A TETERS , Larry R. 4430 341 n1 POKEMPNER, Margo 3460 3413 THOMPSON , Barbara D. 3821 3421 PRATT , Lauren E. 3826 2234B THOMPSON, Moody C., Jr . 3508 3442A RANDELL , Ho lly L. 3786 4515 TVETEN , Lowell H. 3621 3445 REASONER, Rita K. 3184 4522A ROACH, David L. 3253 4524 ROSICH, Rayner K. 3109 3415)1 UTLAUT , William F. 3500 3020 RUSH , Charles )1 . 3460 34ll VanSTORY , Carol B. 3267 3017 RUSSELL , Jane L. 3387 4524B VAUGHAN , Margo S. 4129 4518 VIOLETTE , Edmond J. 3703 3446A VOGLER, Le\\ris E. 3668 3450 SANCHEZ , Patricia A. 4166 2218 SAUER, Joseph A. 4122 4520B SE ITZ , Neal B. 3106 2214 WALLER , Freda L. 3618 2030 SEXTON , Alma B. 3883 3449 WALTERS , Wi lliam D. 4414 3019 SHELTON , Lenora J. 3572 30ll WARNER , Billie D. 4496 3454B WASHBURN , James s. 3798 3413M WASSON , . Gene F. 3584 3430 SKERJANEC , Richard E. 3157 2230 S)JI LLEY , John D. 4218 222ZM SMITH , Dean 3661 2223 WATTERSON , Clark C. 3536 2241 SPAULDING , Arthur D. 4201 2222A WEBER , Bradley D. 3358 34 so SPIES, Kenneth P. 4275 4516B l'.'E LCfl , William )' ., III 4321 3458A WELLS , Paul I. 4368 2235 WIEDER , Bernard 3484 3014 STEARNS , Charles 0 . ' III 3883 3450 STEELE , Francis K. 3815 3420 STEWART , Arthur C. 3998 3419 WORTENDYKE , David R. 4241 2234 STEWART , Frank G. 3336 3450C STOEBE , Suzanne H. 3562 3413 STONEHOCKER, Garth H. 3756 4516D STONER, Russell B. 3572 3009 120 ANNEX IV ITS PUBLICATIONS - FISCAL YEAR 1978 Agy , V. L. , K. D. Boggs , C. M. Me llecker, and G. W. Dougherty , H. T., A. J. Estin , W. L. Morgan , and Haydon (1977) , FY 77 progress report to United J. J. Woodruff (1978) , The Orbiting Standards States Information Agency , Voice of America Platform , Proc . of 1978 Antenna Applications Contract IA-18212-23 , OT Technical Memorandum Symp. , Univ . of Illinois Electrical Engineering 77-245, December , 27 pp . Dept. , Monticello, IL, Sept . 20-22 Akima , H. (1978) , Noise power due to digital errors Dougherty , H. T. , and B. A. Hart (1977) , Tropos in a PCM telephone channel, OT Report 78-139, pheric stratification and anoma lous propagation , January , 40 pp . (NTIS Access. No . PB 277447/AS) Proc . of AGARD Electromagnetic Wave Propagation Panel on Aspects of Electromagnetic Scattering Akima , H. (1978) , Minimum antenna dimensions for in Radio communications, Cambridge , MA, Oct . 3-6 satellite-communications earth stations , OT Report 78-145, April , 92 pp . (NTIS Access. No . Dutton , E. J. (1977) , Precipitation variability in PB 282109/AS ) the U.S.A. for microwave terrestrial system design, OT Report 77-134 , November , 130 pp . Akima , H. (1978) , A method of bivariate interpola (NTIS Access . No . AD A04904l) tion and smooth surface fitting for irregularly distributed data points , ACM Trans . Math. Soft Dutton, E. J. (1978) , Some influences of rainfall on ware i' No . 2, June , pp . 148-159 satellite/ground microwave system installation costs , OT Report 78-142, March, 35 pp . (NTIS Akima , H. (1978) , Algorithm 526 : Bivariate inter Access. No . PB 280272/AS) polation and smooth surface fitting for irregu larly distributed data points {El} , ACM Trans . Dutton , E. J. , and H. T. Dougherty (1978) , Estimates Math . Software i' No . 2, June , pp . 160-164 of the atmospheric transfer function at SHF and EHF , NTIA Report 78-8 , Augu st , 32 pp . (NTIS Arora , R. K. , and J. R. Wait (1978) , Refraction Access . No . not yet available) theories of radio wave propagation through the troposphere--A review, Radio Sci. 13, No . 3, FitzGerrell , R. G. , J. R. Juroshek , and R. D. May-June , pp . 599-600 Jennings (1977) , Earth station antenna measure ments , OT Report 77-129, October , 88 pp . (NTIS Berry , L. A. (1977) , Spectrum metrics and spectrum Access. No . PB 274470/AS ) efficiency : Proposed definitions , IEEE Trans . Electromagnetic Compatibility ------EMC-19 , No . 3, Gallawa , R. L. (1977) , Component development in August , pp. 254-260 fiber waveguide technology , Proc . of First International Telecommun ication Exposition , Berry , L. A. (1978) , User 's guide to low-frequency Atlanta, GA , October 9-15, �' pp . 715-719 radio coverage programs , OT Technical Hemorandum 78-247, January , 91 pp . Gallawa , R. L. , and W. J. Hartman (1977) , Operation al and cost considerations in the use of optical Berry , L. A. (1978) , Effects of local and skywave waveguides in a local information transfer system , interference on CB radio range, NTIA Report OT Report 77-133, November , 79 pp . (NTIS 78-l, May , 9 4 pp . (NTIS Access. No . Access . No . PB 275291/AS ) PB 282889/AS) Gierhart, G. D. , and M. E. Johnson (1978) , Propaga Berry , L. A. (1978) , Technical tradeoffs for tion model (0.1 to 20 GHz) extensions for 1977 spectrum efficiency in a personal radio service , computer programs , U.S. Dept . of Transportation Proc . of 1978 IEEE International Symposium on report FAA-RD-77-129, May , 91 pp . (NTIS Access . Electromagnetic Compatibility , Atlanta, GA , No. ADA 055605) June 20-22 , pp . l-6 Haakinson , E. J. (1978), Spread spectrum : An annota Bloom, L. R. , A. G. Hanson , and L. G. Hause (1977) , ted bibliography , NTIA Special Publication 78-l , Digital transmission via coaxial , twinaxial , and May , 81 pp . (NTIS Access. No . PB 283964/AS ) fiber optical cables , U.S. Army/Communications Electronics Engineering Installation Agency Haakinson, E. J., and R. D. Jennings (1978) , Land Report CCC-CED-XET , October , 140 pp. mobile radio system performance model for VHF and higher frequencies over irregular terrain , Crombie , D. D. , K. Hasselmann , and W. Sell (1978) , Proc . of 28th IEEE Vehicular Technology Confer High-frequency radar observations of sea waves ence, Denver , CO , March 22-24 , pp . 512-517 travelling in opposition to the wind , Boundary Layer Meteorology 13, pp . 45-54 Hartman , W. J. , and D. Smith (1977) , Tilting antennas to reduce line-of-sight microwave link Crow, E. L. (1978) , Relations between bit and block fading , IEEE Trans . Ant . Prop . AP-2-----5, No . 5, error probabilities under Markov dependence, OT September, pp . 642-645 Report 78-143, March, 22 pp . (NTIS Access. No . PB 281545/AS) Hatfield , D. N. (1977) , Measures of spectral effi ciency in land mobile radio , IEEE Trans . Crow , E. L. , and M. J. Miles (1977) , Data analysis Electromagnetic Compatibility �' No. 3, and test design for measuring error rates, Proc . August , pp. 266-268 of International Symposium on �le asurements in Telecommunications , Lannion , France, Oct. 3-7 , Haydon , G. W. (1978) , Theoretical compatibility be pp . 125-130 tween high frequency broadcasting and the high frequency fixed services , OT Technical Memor Crow, E. L. , and M. J. Miles (1977) , Statistical andum 78-252, April, 98 pp . analysis and design of experiments for determin ing digital error rates , Proc. of International Hill, D. A. , and J. R. Wait (1977) , Effect of a Meeting on Data Transmission, Liege , Belgium, lossy jacket on the external fields of a November 21- 22 , !' pp . 119-126 coaxial cable with an interrupted shield , IEEE Trans . Ant. Prop . AP---25, No . 5, September , Dougherty , H. T. (1978) , The OSP survey response , OT p. 726 Technical Memorandum 78-249, February , 444 pp . Hill, D. A. , and J. R. Wait (1977) , Analysis of Dougherty , H. T. , and E. J. Dutton (1978) , Estimat radio frequency transmission in a semicircular ing year-to-year variability of rainfall for mine tunnel containing two axial conductors, microwave applications, IEEE Trans . Commun. IEEE Trans. Commun . -----COM-25 , No . 9, September , �' No . 8, August, pp . 1321-1324 pp. 1046-1050 121 Hill , D. A. , and J. R. Wait �1977) , Electromagnetic Kissick, w. A. , and G. H. Stonehocker (1977) , Elec scattering from an unbonded rectangular wire tromagnetic Cosite Analysis (EMCAN) Model--Part mesh located near the air-ground L1terface , I: The feasibility study, OT Report 77-130 , October, 75 pp . (NTIS Access. No . PB 27508 6/AS) IEEE Trans. Electromagnetic Compatibility EMC------19, No . 4, November , pp . 402-406 Liebe , H. J. , and G. G. Gimme stad (1978) , Calculation Hill, D. A. , and J. R. Wait (1977) , Ana lysis of of clear air EHF refractivity , Radio Sci . --13 , alternating current excitation of a wire rope by No . 2, March-April, pp . 245-251 a toroidal coil, J. Appl. Phys . --48, No . 12, December, pp . 4893-4897 Linfield, R. F. (1977) , Radio channel capacity limi tations, OT Report 77-132, November , 91 pp . Hill , D. A. , and J. R. Wait (1978) , The impedance of (NTIS Access. No . PB 275239/AS ) dipoles in a circular tunnel \Vith an axial con ductor, IEEE Trans . Geosci. Electron . GE------16, Linfield, R. F. , and T. de Haas (1978) , Interfacing No . 2, April, pp . 118-126 the Automated Maritime Mobile Telephone System with the U.S. public switched telephone network , Hill, D. A. , and J. R. Wait (1978) , Scattering by a NTIA Report 78-7, August , 66 pp . (NTIS Access . slender void in a homogeneous conducting wire No . not yet avai lable) rope , Ap pl . Phys . 16, pp . 391-398 Linfield, R. F. , and M. Nesenbergs (1978) , Access Hill , D. A. , and J. R. Wait (1978) , Surface wave area switching and signaling : Concepts, issues, propagation on a rectangular bonded wire mesh and alternatives , NTIA Report 78-2 , May , 146 pp . located over the ground , Radio Sci . --13, No . 5, (NTIS Access . No. PB 283464/AS) September-October Longley, A. G. (1978) , Radio propagation in urban Howard, A. Q. , Jr . (1977) , Microbend losses in areas , Proc . of 28th IEEE Vehicular Technology multimode optical fibers , OT Report 77-136, Conference , Denver , CO , March 22-24, pp . 503-511 November , 51 pp . (NTIS Access . No . PB 275387/AS ) Longley, A. G. (1978) , Radio propagation in urban Hubbard , R. W. (1977) , Measurements in microwave areas , OT Report 78-144 , Ap ril, 55 pp . (NTIS telecommunication systems using a pseudo-random Access. No. PB 282109/AS ) noise (PN) probe , Proc . of International Sympo sium on Measurements in Telecommunications , Ma , M. T. , and R. G. FitzGerrell (1977) , Design of a Lannion , France , Oct . 3-7 , pp . 514-519 van-top low-profile HF antenna , 0'1' Report 77-131 , October, 42 pp . (NTIS Access. No . PB 275091/AS ) Hubbard , R. W. , R. F. Linfield, and W. J. Ilartman (1978) , Measuring characteristics of microwave Ma , M. T. , and R. A. McLean (1978) , Application mobile channels, Proc . of 28th IEEE Vehicular scenario for electromagnetic radiation hazards , Technology Conference, Denver , CO, March 22-24, OT Technical Memorandum 78-250 , March , 104 pp . pp . 519-526 Hatheson, R. J. (1977) , A Radio Spectrum Measurement Hubbard, R. W. , R. F. Linfield, and W. J. Hartman System for frequency management data, IEEE Trans . (1978) , Measuring characteristics of microwave Electromagnetic Compatibility ------EHC-19, No . 3, mobile channels, NTIA Report 78-5, June , 53 pp. August, pp. 225-230 (NTIS Access . No . PB 283944/AS ) Hatheson , R. J. (1977) , A Radio Spectrum Heasurement Janes , H. B. , J. T. Collins, and F. K. Steele (1978) , System for frequency management data , Proc . of A Preliminary catalog of programs and data for International Sympo sium on Measurements in Tele 10-100 GHz radio system predictions, OT Report communications , Lannion, France , Oct . 3-7 , 78-141, March , 50 pp . (NTIS Access . No . pp. 540-545 PB 280774/AS) Matheson, R. J. (1978) , Automated spectrum analysis , Janes , H. B. , and M. C. Thompson , Jr. (1978) , Fading Proc . IEEE �' No . 4, April, pp . 392-402 at 9.6 GHz on an experimentally simulated aircraft-to-ground path , IEEE Trans. Ant . Prop . Middleton , D. (1978) , Statistical-physical models of AP-26, No . 5, September, pp . 715-719 man-made and natural radio noise, Part III . First-order probability models of the instantan Jennings , R. D. , and S. J. Paulson (1977) , Communi eous amplitude of Class B interference, NTIA cation system performance model for VHF and Contractor Report 78-l , June , 74 pp . (NTIS higher frequencies , OT Report 77-128, October , Access. No . PB 284862/AS) 175 pp . (NTIS Access. No . PB 274458/AS ) �li les, M. J. (1978) , Accuracy-cost study for the Johnson , M. E. , and G. D. Gierhart (1978) , Applica USPS Electronic Message Service System , OT tions guide for propagation and interference Technical Memorandum 78-248, February , 40 pp . analysis computer programs (0.1 to 20 GHz) , U.S. Dept . of Transportation report FAA-RD-77-60 , Minor , P. C., and L. E. Wood (1977) , A new state of �larch , 184 pp . (NTIS Access. No . ADA 053242) the art in Ef1C field measurement instrumentation , IEEE Trans. Electromagnetic Compatibility �· Johnson, M. E. , and G. D. Gierhart (1978) , Aerospace No . 3, August, pp . 230-236 propagation prediction capabilities associated with the IF-77 model , Proc . of AGARD meeting of Nesenbergs, f1 . (1978) , Bounds on the number of pos Electromagnetic Wave Propagation Panel, Ottawa , sible distinct networks, IEEE Trans . Cornrnun . Canada , April 24-28 , pp. 47-l - 47-13 COH-26 , No . 8, August , pp . 1315-1318 Johnson , R. B. (1977) , Federal regulations relevant Newton, c. w. , R. c. Miller, E. R. Fosse , D. R. to the structural development of telecommunica Booker, and P. M. McManamon (1978) , Severe tions industries , OT Report 77-135, November, thunderstorms : Their nature and ·their effects on 65 pp . (NTIS Access . No . PB 275238/AS ) society , Interdisciplinary Sci . Rev. l• No . l, pp . 71-85 Juroshek , J. R. , G. E. Wa sson , and G. H. Stonehocker (1978) , Flight tests of digital data transmission , Ott , R. H., and M. C. Thompson (1977) , Coherence IEEE Trans. Aerospace Electron . Systems ------AE S-14, bandwidth in turbulence, Ann . Telecomrnunic . E• No . 2, March , pp . 403-410 Nos. 11-12, November-December , pp . 536-540 Kimrnett , F. G. , :and N. B. Seitz (1978) , Digital com Ott , R. H., and M. C. Thompson, Jr. (1978) , Atmos munication performance parameters for proposed pheric amplitude spectra in an absorption region , Federal Standard 1033, Volume II: Application IEEE Trans . Ant . Prop . AP-2 6, No . 2, March , Examples, NTIA Report 78-4, May , 66 pp . (NTIS pp . 329-332 Access. No . PB 284235/AS ) 122 Payne , J. A. (1978) , ARPANET Host to Host access and disengagement measurements , NTIA Report 78-3, May , 63 pp . (NTIS Acce ss . No . PB2 83554/AS ) Sailors , D. B. , c. P. Kugel, and G. W. Haydon (1977) , Predicting the compatibility of high frequency sky-wave communication systems , IEEE Trans. Electromagnetic Compatibility ------EMC-19, No. 3, August , pp . 332-343 Seidel , D. B. , and J. R. Wait (1978) , Transmission AVA ILABILITY OF PUBLICATIONS - modes in a braided coaxial cable and coupling to a tunnel environment , IEEE Trans . Microwave OT/NTIA Reports , Special Publications , and Contractor Theory Tech. MTT- 26, No . 7, July , pp . 494-499 Reports are available from the National Technical Information Service . Order by accession number Seitz , N. B. , and P. M. McManamon (19 77) , Digital shown in publications listing . Technical Memo randa commun ication performance parameters , Proc. of are not generally avai lable , but additional First International Telecommunication Exposition , information may be secured by contacting the author . Atlanta , GA, October 9-15, �. pp . 577-586 Reque sts for copies of journal articles should be addressed to the journal . Seitz , N. B. , and P. M. McManamon (1977) , A system atic approach to the development of performance parameters, Proc . of First International Tele communication Exposition , Atlanta, GA , October 9-15, �. pp . 859-865 Seitz , N. B. , and P. M. �lcllanamon (1978) , Digital communication performance parameters for pro posed Federal Standard 1033 , Volume I: Standard Parameters , NTIA Report 78-4 , 11ay , 175 pp . (NTIS Access . No. PB 283580/AS ) Spaulding , A. D. , and G. H. Hagn (1977) , On the ADDENDUM : definition and estimation of spectrum occupancy , IEEE Trans . Electromagnetic Compatibility Janes, H. B. (1978) , Notes on power spectrum analysis EMC- 19, No . 3, August, pp . 269-280 using a desktop computer , NTIA Technical Memo randum /8-2, September, 28 pp . Spaulding , A. D., and G. H. Hagn (1978) , Worldwide minimum environmental radio noise levels (0.1 Hz Hiddleton , D. (1978) , Statistical-physical mode ls of to 100 GHz) , Proc . of 1978 Symposium on the man-made and natural radio noise : Part IV . Effects of the Ionosphere on Space and Terres Determination of the first-order parameters of trial Systems , Washington , D.C., January 24-26 , Class A and B interference , NTIA Contractor Naval Research Laboratory, Office of Naval Report 78-2 , September , 58 pp . (NTIS Access . Research No . not yet avai lable) Spaulding , A. D. , and D. Middleton (1977) , Optimum Juroshek , J. R. (1978) , A preliminary estimate of reception in an impulsive interference environ the effects of spread-spectrum interference on ment--Part I: Coherent detection, IEEE Trans . TV, NTIA Report 78-6 , June , 26 pp . Commun . COM-25, No . 9, September , pp . 910-923 Spaulding , A. D. , and D. Middleton (1977) , Optimum reception in an impulsive interference environ ment--Part II: Incoherent reception , IEEE Trans . Commun . COM- 25, No . 9, September, pp . 924-934 Steele , F. K. , and A. H. Diede (1977) , A comparison of nighttime propagation anoma lies observed at two very low frequencies , Radio Sci . --12 , No . 5, September-October , pp . 791-796 Utlaut , W. F. (1978) , Spread-spectrum principles and possible application to spectrum utilization and allocation, ITU Telecommun . J. 45, No . 1, January , pp . 20-32; IEEE Com soc-Mag , Sept. ,pp. 21-30 Wait , J. R. , and D. A. Hill (1978) , Analysis of the dedicated communication line in a mine tunnel for a shunt-loaded trolley wire, IEEE Trans . Commun . COM-�, No . 3, March, pp . 355-361 Watterson , C. C. (1978) , 616A and Verdin back-to-back compatibility tests , sets 1-3 (U) , OT Technical Memorandum 78-246C (SECRET) , January, 94 pp . We lls, P. I. (1977) , The attenuation of UHF radio signals by houses, IEEE Trans . Vehicular Tech. VT- 26, No . 4, November , pp . 358-362 We lls, P. I. (1978) , Current activities in small earth terminal satellite domestic telecommunica tions , NTIA Report 78-9, August, 136 pp . 123 ANNEX V GENERAL AND HISTORICAL INFORMAT ION OF ITS The Institute for Telecommun ication Sci was completed in 1954 , during which year ences , largest component of the National President Eisenhower dedicated the NBS Telecommunications and Information Admini Radio Building . The Radio Standards pro stration, is located at the Boulder Lab gram left CRPL at the time of the move to oratories of the Department of Commerce Boulder , and has pursued a parallel exist and has (as of Sept . 30, 1978) a full - time ence at Boulder in NBS since that time . permanent staff of 100 and other staff of 45. In FY 1978 , its support consisted of In 1954 , CRPL consisted of two research $1.9 million of direct funding from Com divisions : Radio Propagation Physics and merce and $7.5 million in work sponsored Radio Propagation Engineering . The Radio by other Federal agencies . Systems Division was formed in 1959 . In 1960, the Upper Atmosphere and Space Phys The Boulder Laboratories include research ics Division and the Ionosphere Re search and engineering components of the National and Propagation Division were formed from Bureau of Standards , the National Oceanic the Radio Propagation Physics Division . and Atmospheric Administration, and the In 1962 , CRPL received a full-time Direc National Telecommunications and Informa tor , Dr . C. Gordon Little . In 1965 , Dr . tion Administration . Common administra H. Herbert Holloman , first Assistant Sec tive services are the rule in the Boulder retary for Science and Technology in Com Laboratories . The Radio Building , which merce , implemented a decision to un ify houses ITS , is on the National Bureau of geophysics in Commerce with the creation Standards campus at 325 Broadway . In of the Environmental Science Services add ition to ITS , the National Telecommun i Administration (ESSA) , made up of the cations and Information Administration Weather Bureau , the Coast and Geodetic also has its Boulder Divi sion of the Survey , and the Central Radio Propagation Office of Policy Analysis arid Development Laboratory . At that time , the CRPL was located in the 30th Street Building off renamed the Institute for Telecommun ica Baseline Road in Boulder. tion Sciences and Aeronomy (ITSA) . In 1967 , the Institute for Telecommun ication The following brief history shows its NBS Sciences came into being . It contained beginning s. The Radio Section of the the telecommunications-oriented activities National Bureau of Standards was founded of ITSA. Dr . E. K. Smith served as an prior to World War I, and played a major interim Director for one year and wa s role in the evolution of our understanding followed by R. c. Kirby who was Director of radio propagation . Dr . J.H. Dellinger , for the ensuing three years . its director for mo st of the period up until World War II, was strongly convinced Meanwhile , in Washington , major attention of the importance of research and gave it was being given to the organization of practical application as first Chairman of telecommunications in the Federal estab the Study Group on Ionosphere Propagation lishment, and the Department of Commerce in the CCIR. established an Office of Telecommun ications in 1967. Reorganization Plan No . 1 of During World War II, the Interservice 1970 and Executive Order 11556 established Radio Propagation Laboratory (IRP L) was the Office of Telecommunications Policy organized at the National Bureau of Stand (OTP ) in the Executive Office of the Pres ards , under the direction of Dr . Dellinger . ident , and assigned additional responsi His group provided a common focus for bilities to the Secretary of Comme rce in military needs in propagation during the support of OTP . To meet these responsi war . In 1946, the Central Radio Propaga bilities , the Office of Telecommunications tion Laboratory (CRPL) wa s established , (OT) was given expanded responsibilities and in its early years had direct ties on September 20, 1970, and ITS , along with with the Defense Department ; for example, its programs , property , personnel , and senior officials of DoD would appear be fiscal resources was transferred to OT . fore Congress to defend the CRPL budget . In 1949, Congressional concern for the In 1971, Douglass D. Crombie became Dir vulnerab ility of government laboratories ector of ITS . ITS has shi fted from its located in Washington , D.C. , and the strong emphasis on radio wave propagation crowding of the NBS Connecticut Avenue and antennas since 1970, in the direction campus made it advisable for the radio of applications in spectrum management and research work to be taken elsewhere . in telecommun ication systems . Three sites , one in California , one in In March 1978, President Carter signed Colorado , and one in Illinois , were con Executive Order 12046 which established sidered , and Boulder , Colorado , was selec the National telecommun ications and Infor ted . The first group from CRPL, which at mation Administration and merged some of that time included radio standards work , the functions of the Office of Telecom moved to Colorado in 1951, and the move munications Policy with those of the Office 125 of Telecommun ications in the new agency . The Department of Defense has long been ITS was assigned the responsibility of the primary source of advanced technology . managing the te lecommun ications technology At the present time , the largest part of research programs of NTIA and providing the other agency sponsorship of ITS comes research support to other elements of NTIA from needs of the Department of Defense . as well as othe� agencies on a reimburs However, there is also a clear need for able basis . Among other assigned tasks , relevance to national goals on the civil the Institute was to remain " ...the ian side of the Federal establishment . central Federal Government laboratories ITS is there fore moving to increase its for research on transmission of radio work with the civil side of the Federal waveS a11 Government . The agencies in the civilian sector are frequently also in the high ITS and its predecessor organizations have technology area; for example , the FAA and always played a strong role in pertinent NASA, for which ITS has done , and contin scientific (URS I ), pro fessional (IEEE) , ues , very important work in navigation , national (IRAC) , and international (CCIR) collision avo idance, satellite communica governmental activities . The Director of tions , and related work . CCIR from 1966 to 1974 was Jack W. Herb streit, a former Deputy Director of CRPL and ITSA , and the current CCIR Director is Richard C. Kirby , formerly Director of ITS . At the present time , the u.s. preparatory work for three of the eleven Study Groups of CCIR is directed by members of ITS (U.S. Study Groups 1, 3, and 5) , and staff members of ITS participate in many of the other Study Groups . ITS actively supports the Interdepartment Radio Advisory Commit tee (IRAC) , and the Chairmen of its Stand ards Wo rking Group (J.A. Hull) and the Propagation Wo rking Group (W.F. Utlaut ) of the Technical Subcommittee are members of ITS management . The work wh ich ITS does for other agencies in the government derives its legal authorities from 15 U.S.C. 272 (e) "Advi sory Services to Government Agencies on Scientific and Technical Problems " and 15 u.s.c. 272 (f) "Invention and Development of Devices to Serve Special Needs of Government ." As a matter of Federal pol icy , NTIA does not accept work more appropriately done by other non-government or government organizations . It is also a matter of policy that all sponsored work reinforce NTIA' s overall program and that it be clear that other agencies, indus tries, or universities could not serve equally we ll or better . Within these policy guides, ITS aspires to being the Federal laboratory for research in telecommunications . It is clear that the government has a responsibility to pursue long-range studies in telecommuni cations which are not economically profit able for industry . It is also clear that the government must have its own , inde pendent laboratories to assess the sig nificance of research conducted elsewhere . Towards the se ends , ITS strives to ma in tain a knowledgeable staff that is \vo rking on the frontiers of technology and is in touch with the telecommun ications problems of the Federal Government . Its programs and future directions are succinctly given in the Foreword and Introduction of this report by ITS Director D.D. Crombie . 126 f:r U,&, GOVERNMENT PRINTING OFFICE: 1978�0· 677·25 t /1 63 INSTITUTE for TELECOMMUNICATION SCIENCES Director - Douglass 0 . Crombie Deputy Director - Or. William F. Utlaut Secretary - Beverle J. Gibson BUDGET & ACCOUNTING PUBLICATION I INFORMATION CONSULTANT PROGRAM DEVELOPMENT I William D. Walters I Russell B. Stoner Or. James R. Wait I I Dr. Bernard Wieder I I I I I DIVISION 1 DIVISION 2 DIVISION 3 SPECTRUM UTILIZATION SYSTEM TECHNOLOGY & STANDARDS APPLIED ELECTROMAGNETIC SCIENCE Associate Director - Donald L lucas Associate Director - John P. Murray Associate Director · Joseph A. Hull Secretary - Jean R. Mollard Secretary - Marylyn N. Olson Consultant · George W. Haydon Advisor · Dr. Hans J. Liebe RADIO SPECTRUM ANTENNA CHANNEL ASSISTANT TO SPECTRUM EXTENSION I ADMINISTRATIONI I OCCUPANCY PERFORMANCE CHARACTERIZATION THE ASSOCIATE DIRECTOR RESEARCH & ANALYSIS I-- Robert J. Matheson Richard G. FitzGerrell Robert W. Hubbard John M. Harman Arthur C. Stewart Dr. Moody C. Thompson EMC ANALYSIS VHF I UHF MODELS SYSTEMS ENGINEERING SYSTEMS PERFORMANCE PREDICTIONS DEVELOPMENT MOBILE SYSTEMS ANALYSIS TECHNOLOGY MODEL DEVELOPMENT & & & - & !! Jean E. Adams Or. George A. Hufford Joseph A. Hull (Acting) Thijs deHaas Or. Charles M. Rush SYSTEMS NEW TECHNOLOGY ADVANCED ANALYSIS ADVANCED COMMUNICATION ASSESSMENT DEVELOPMENT & SPECIAL PROJECTS TECHNOLOGY & APPLICATIONS Dr. Peter M. McManamon louis R. Bloom Donald L. lucas (Acting) William 8. Grant