DOCSLIB.ORG

Sandeep Baruah, Scientist-E Vigyan Prasar Department of Science

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Sandeep Baruah, Scientist-E Vigyan Prasar Department of Science Sandeep Baruah, Scientist-E Vigyan Prasar Department of Science & Technology C-24, Qutab Institutional Area New Delhi-110 016 E-mail: [email protected] CONTENT Part-I: Introduction to ham radio PAGE A. What is Ham Radio? 1 B. Why an Amateur Radio Operator is called a ham? 2 C. What is the minimum qualification to become a ham? 3 D. What is an amateur radio call-sign? 3 Part-II: Amateur Radio Rules & Regulation A. Detailed procedures related to application for a ham radio licence. 4 B. Different grades of licencing examinations and licences. 5 C. The Indian Wireless Telegraphs (Amateur Service) Rules, 1978. 6 D. Syllabus of Amateur Station Operator's Certificate (ASOC) Examination. 28 E. Question and answer section on amateur radio rules & regulations 33 F. Radio telephony operating procedure. 41 G. Radio telegraphy operating procedure. 43 Part-III: Radio Theory and Practice A. Elementary theory of electricity & magnetism 47 B. Thermionic emission & valves 77 C. Semiconductor devices 80 D. Radio receivers 86 E. Transmitter 97 F. Radio wave propagation 103 G. Aerials 109 Part-IV: Learning the International Morse Code. 117 Part-V: Safety measures in a ham radio shack. 121 Annexure-I: List of Wireless Monitoring Stations Annexure-II: Call-sign Prefixes of Amateur Radio Stations of different countries allotted by the International Telecommunication Union (ITU) Annexure-III: Sample Question Papers for the Amateur Radio Licencing Examination TIFAC-IDRiM Conference 28th –30th October 2015 New Delhi, India RADIO BASED APPROACH FOR DISASTER RISK REDUCTION AND MANAGEMENT USING AUTOMATIC PACKET REPORTING SYSTEM (APRS®) AND HAM RADIO (AMATEUR RADIO) DIGITAL COMMUNICATION TECHNOLOGIES S. BARUAH Vigyan Prasar, Department of Science & Technology C-24, Qutab Institutional Area New Delhi 110 016 [email protected] ABSTRACT In the event of any large scale disaster, due to the breakdown of conventional modes of communication (mobile phone, land line phone, Internet etc.) disaster management becomes a difficult task for various governmental and non-governmental emergency responders. So it is of utmost importance to keep in place an alternative communication service up and running which can work as a second line of communication utilizing radio waves. During many of the past large scale disasters all over the world, Amateur Radio Service (ham radio) proved its efficacy in quick dissemination of disaster management information (search and rescue, relief work, tracking of missing person, real-time plotting of vehicles and personnel involved in disaster management, transmission of weather telemetry data etc.). Amateur Radio Service is a non-commercial licensed service utilized by voluntary radio experimenters and radio enthusiasts regulated by the telecommunication authority. Automatic Packet Reporting System -- APRS® (Registered Trademark of Bob Bruninga, US Naval Academy) is a digital radio communication technology which augments the scope of application of Geographical Information System (GIS) for disaster management. Vigyan Prasar is involved in coordination of disaster management activities during many of the past large scale disasters gaining expertise in digital technologies for disaster risk reduction and management through its state- of-the-art radio communication system. 1. INTRODUCTION Most of the disasters are unpredictable and in a country as big as India with population exceeding 120 crore, it creates havoc in terms of loss of human life and other valuable property. Governmental agencies and NGOs employ different means to predict location, route and extent of disaster with a probable time frame. Due to the lack of adequate low-cost radio technology infrastructure in our country, the emergency responders are facing problems in disaster risk reduction works, pre-disaster communication in disaster prone areas and post- disaster management. The author being a licensed amateur radio experimenter (ham radio hobbyist) with the government allotted call-sign VU2MUE (Baruah, 1999a) for the last twenty five years (licensed in 1989) was involved in emergency disaster communication during many of the large scale disasters (Arya, A.S., et. al. 2005 and 2006) that our country has gone through. A study was done by Baruah in 2004a on Ham Radio for Disaster Communication. The role of ham radio operators in India during the Tsunami disaster in 2004 was documented in details by Baruah, 2004b. Baruah, 2012 discussed in detail about live RF data on an interactive Internet map. It is realized that without the integration of GIS Technology and Amateur Radio Digital Communication Technology at grass root level Emergency Operation Centres (EOCs), it would remain a far flung dream for the government to come out with a mechanism that would not only ensure an effective linkage between the people living is disaster prone areas with that of those who are involved in disaster management. A countrywide Amateur Radio emergency digital communication network can be established under the Indian Wireless Telegraph Amateur Service Rules of the Department of Telecommunications (Baruah, 1999b). 2. MATERIALS AND METHOD 2.1 GEOGRAPHICAL INFORMATION SYSTEM (GIS) AND PACKET RADIO Geographical Information System (GIS) broadly describes any information system that integrates, stores, edits, analyses, shares and displays geographic information (called the geospatial data) for decision making in an interactive map. For government licensed amateur radio experimenters (most of whom might not have the professional knowledge of GIS) to use their two-way radio communication equipment for automatic transmission of GIS data/information, Automatic Packet Reporting System (APRS) is the most suitable mode. APRS (Bruninga, 2002) is evolved from its predecessor ham radio communication technology called Packet Radio (Ackermann, 2002) which is a digital mode of Amateur Radio (Ham Radio) communications which corresponds to computer telecommunications. The telephone modem is replaced by a "magic" box called a terminal node controller (TNC); the telephone is replaced by an amateur radio transceiver (a combined unit of radio transmitter and receiver), and the phone system is replaced by the "free" amateur radio waves. Packet radio takes any data stream sent from a computer and sends that via radio to another amateur radio station similarly equipped. Packet radio is so named because it sends the data in small bursts, or packets (Kenney, 1995). Interfacing of the computer through its serial communication port (RS232) to the two-way radios is done through suitable radio modems. In the absence of RS232 serial ports, serial to USB adaptor cables are utilized by radio experimenters which provide 1200 baud and 9600 baud data transmission speed in the government allotted Very High Frequency amateur band (VHF: 144-146 MHz) and Ultra High Frequency (UHF: 434 to 438 MHz) amateur bands. 9600 baud is approximately 960 unencrypted digitally transmitted characters in one second. Though amateur radio experimenters have been utilizing the AX.25 Packet Radio protocol (Beech et.al, 1998) since late 70s for transmission of texts (transfer of text files from one computer to another computer using radio waves), data, binary file transfer over the radio and for two way interactive digital communication (text chat as well as Bulletin Board System for file/mail storage and retrieval) using walkie-talkies interfaced to the computer, in the recent time Automatic Packet Radio System (APRS®) is gaining popularity as it provides all the information graphically on a map that is of immense utility in disaster management. Graphical representation (through standardized icons) of various geospatial information (e.g. Earthquake, cyclone, relief camp, Emergency Operation Centre-EOC, ambulances, hospitals, different type of vehicles etc. (Figure 1, 2 and 3) make all emergency management related information available to the emergency responders just at the click of the mouse button. Open source and free computer software like UI-VIEW (Barker, 2004) and APRSIS32 (Deffenbough, 2009) are available on the internet for different operating system which can be utilized at the Emergency Operation Centres (EOCs) for transmission and monitoring of geospatial information on maps using radio. IGate (Bruninga, 2015) is a radio to internet gateway system utilized by ham radio operators to feed radio frequency data to internet and make these available all over the world. 2.2 PACKET RADIO STATION For APRS® to be utilized for disaster risk reduction and disaster management, the basic packet radio station consist of a Very High Frequency (VHF) two-way radio interfaced to the computer through a TNC (Terminal Node Controller) and a software application for digital communication (Figure 1) The two way radio is connected to an external antenna for transmission and reception of digital data. The function of the TNC is to encode and decode the data. The software, also sometime called a terminal programme displays the data in human readable format. The GUI (Graphical User Interface) software also allows the user to connect to a station, sending text message as well as transfer of files from his/her computer to the other connected computer (connected through radio waves). Packet is communications between people either director indirect. Emergency responders can work keyboard to keyboard or use electronic mailboxes to leave messages. Due to error checking by the TNC, all of it is error free, too. As the data is received it is continuously
Load more

Recommended publications
  • Jazz and Radio in the United States: Mediation, Genre, and Patronage
    Jazz and Radio in the United States: Mediation, Genre, and Patronage Aaron Joseph Johnson Submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy in the Graduate School of Arts and Sciences COLUMBIA UNIVERSITY 2014 © 2014 Aaron Joseph Johnson All rights reserved ABSTRACT Jazz and Radio in the United States: Mediation, Genre, and Patronage Aaron Joseph Johnson This dissertation is a study of jazz on American radio. The dissertation's meta-subjects are mediation, classification, and patronage in the presentation of music via distribution channels capable of reaching widespread audiences. The dissertation also addresses questions of race in the representation of jazz on radio. A central claim of the dissertation is that a given direction in jazz radio programming reflects the ideological, aesthetic, and political imperatives of a given broadcasting entity. I further argue that this ideological deployment of jazz can appear as conservative or progressive programming philosophies, and that these tendencies reflect discursive struggles over the identity of jazz. The first chapter, "Jazz on Noncommercial Radio," describes in some detail the current (circa 2013) taxonomy of American jazz radio. The remaining chapters are case studies of different aspects of jazz radio in the United States. Chapter 2, "Jazz is on the Left End of the Dial," presents considerable detail to the way the music is positioned on specific noncommercial stations. Chapter 3, "Duke Ellington and Radio," uses Ellington's multifaceted radio career (1925-1953) as radio bandleader, radio celebrity, and celebrity DJ to examine the medium's shifting relationship with jazz and black American creative ambition.
    [Show full text]
  • Tlu Lictutstilnatttatt ^ W T? Fmmrlrrl 1885
    tlu lictutstilnatttatt ^ W T? fmmrlrrl 1885 ■•■''' lily . , , Vol. \CIX.\o.6l I'llll AHHPHIA.July I. 1983 Minority admissions fall in larger Class of 1987 Officials laud geographic diversity B> I -At KfN ( (II I MAN the) are pleased with the results ol a \ target class ol 1987 contains dtive 10 make the student bod) more liginificantl) fewei minority geographicall) diverse, citing a students but the group is the Univer- decrease in the numbet ol students sity's most geographicall) diverse from Ihe Northeast in the c lass ol class ever. 198". A- ol late May, 239 minority ot the 4191 students who were at -indents had indicated the) will cepted to the new freshman class. matriculate at the i niversit) in the 2178 indicated b) late \lav that the) fall as members ol the new will matricualte, a 4" percent yield. freshman class, a drop ol almost 5 Provost l hi'ina- Ehrlich said that percent from last year's figure of increasing geographic diversit) i- 251. one ol the I Diversity's top goal-. Acceptances from t hicano and "I'm ver) pleased particularl) in Asian students increased this vear, terms of following out goal of DP Steven Siege bin the number of Hacks and geographic diversit) while maintain- I xuhcranl tans tearing down the franklin Held goalpost! after IRC Quakers" 23-2 victor) over Harvard latino- dropped sharply. Hie new ing academic quality," he said. "The freshman class will have 113 black indicator- look veiv good." -indents, compared wilh 133 last Stetson -.ml the size ol the i lass veat a decline ol almost 16 per ol 1987 will not be finalized until cent tin- month, when adjustments are Champions But Vlmissions Dean I ee Stetson made I'm students who decide 10 Bl LEE STETSON lend oilier schools Stetson said he said the Financial MA Office i- 'Reflection oj the econom\' working to provide assistance winch plan- "limited use" ol the waiting will permit more minority students list to fill vacancies caused by an Iwentv two percent ol the class Quakers capture Ivy football crown to matriculate.
    [Show full text]
  • Cooperative Program Tape Networks in Noncommercial EDRS
    DOCUMENT RESUME ED 115 254 IR 002 798 AUTHOR Nordgren, Peter D. TITLE Cooperative Program Tape Networks in Noncommercial Radio. PUB DATE Dec 75 NOTE 94p. EDRS PRICE MF-$0.76 HC-$4.43 Plus Postage DESCRIPTORS *Cooperative Programs; *Educational Radio; Higher Education; *Programing (Broadcast); *Questionnaires; Shared Services; Statistical Data; Tables (Data) IDENTIFIERS Cooperative Program Tape Networks ABSTRACT Over 200 noncommercial radio stations responded to a survey to gather data on the characteristics of member stations and to sample the opinion of nonmembers toward a cooperative network concept. A second survey of 18 networks sought to gather indepth information on network operation. Results showed that 22.2 percent of the stations surveyed were participating in program cooperatives, and over 79 percent felt that network participation would be beneficial. It was concluded that the cooperative program tape network should continue in order to fulfill specialized programing needs. A copy of the two questionnaires, the letter of transmittal, and the mailing list is appended. A list of the networks that participated in the study, 12 statistical tables, and a 20-item bibliography are included. (Author/DS) lb *********************************************************************** * Documents acquired by ERIC include many informal unpublished * * materials not available from other sources. ERIC makes every effort * * to obtain the best copy available. Nevertheless, items of marginal * * reproducibility are often encountered and this affects the quality * *of the microfiche and hardcopy reproductions ERIC makes available * *via the ERIC Document ReproductionService (EDRS). EDRS is not * *responsible for the quality of theoriginal document. Reproductions* *supplied by EDRS are the best thatcan be made from the original.
    [Show full text]
  • 70 Per Cent Would Fund
    tviauison lAmege ktuiaij Harrisonburg, Virginia Vol. LIV Tuesday September 21, 1976 Madison College, Harrisonburg. Va No. 6 70 per cent would fund: Students support Chrysalis By SANDV AMANN not do "anything contrary to in a portfolio, brought the More than 70 percent of the what people want," he strongest negative reaction. student body believs the believes that a "more ap- One third of those responding Student Government propriate question would be: rated it "poor" or "very Association (SGA) should would you rather have the poor". No other aspect of the continue funding the Chrysalis Chrysalis, or a carrier current magazine received a similar at its present level or give it radio station and faculty response. more money, according to a evaluation booklet?" The Chrysalis has had to Breeze survey. Anestos added that the SGA fight for funds for the past Out of 109 returning was left with a small budget three years, according to sophomores, juniors and for the year and probably adviser Todd Zeiss. The seniors 56 percent said the would not be able to fund all magazine has been budgeted literary magazine should be three projects. for $6500 this year. funded at the same level it is In the survey, students "I think the Chrysalis has now, and 15 percent said it were asked to rate last year's lived up to its intent to present should be given more money Chrysalis from "very poor" to the best of student production - Twenty-six people, 23.8 "very good" In the overall in different, experimental percent, said the SGA should category, a majority of ways," Zeiss said.
    [Show full text]
  • Motion for Stay Pending Appeal General Counsfj
    Before the UNITED STATES COPYRIGHT OFFICE LIBRARY OF CONGRESS Washington, DC DRlr.lNAl In the Matter of Determination of Reasonable Rates Docket No. 2000-9 CARP and Terms For the Digital Performance DTRA 18:2 Of Sound Recordings and Creation of Ephemeral Phonorecords IMCEIJUvZDo SP so Ãm MOTION FOR STAY PENDING APPEAL GENERAL COUNSFJ. OF COPYRIGHT Live365.com, Inc. John O. Jeffrey Executive Vice President Corp. Strategy and General Counsel Elizabeth H. Rader Stanford Law School Center for Internet 8 Society 559 Nathan Abbott Way Stanford, CA 94305-8610 (650) 724-0517 September 27, 2002 TABLE OF CONTENTS I. Introduction. 11. The Librarian Can And Should Grant A Stay For All Parties Bound By The Determination. To Preserve The Status Quo Pending Appeal. III. The Webcasters Will Prevail On The Merits Of Its D.C. Circuit Appeal ... A. The Rates in the Librarian's Final Rule Place Webcasting Out ofReach of All But Profitable, Commercial Entities and Therefore. Violates The First Amendment. B. Live365 Will Prevail On Appeal Because The Rates Chosen Frustrate The Statutory Purpose ofEliminating Transaction Costs To Facilitate and Encourage Webcasting of Copyrighted Works. C. Live365 Will Prevail Because The Librarian Acted In An Arbitrary Manner By Setting Rates Using The RIAA/Yahoo! Agreement As A Benchmark 13 D. Live365 Will Prevail On Appeal Because The Librarian Acted Arbitrarily By Accepting A Recommendation That Condoned The Panel's Ignoring The National Public Radio License......................................................... .18 E. Live365 Will Prevail On Appeal Because The Librarian Acted Arbitrarily By Accepting A Recommendation That Condoned The Panel's Rejection of the Musical Works Benchmark.
    [Show full text]
  • Contributors to This Issue Herbert E. Ives, BS, University of Pennsylvania
    Contributors to this Issue Herbert E. Ives, B.S., University of Pennsylvania, 1905; Ph.D., Johns Hopkins, 1908; assistant and assistant physicist, Bureau of Standards, 1908-09; physicist, Nela Research Laboratory, Cleveland, 1909-12; physicist. United Gas Improvement Company, Philadelphia, 1912-18; U. S. Army Air Service, 1918-19; research engineer, Western Electric Company and Bell Telephone Laboratories, 1919 to date. Dr. Ives' work has had to do principally with the production, measurement and utilization of light. Frank Gray, B.S., Purdue, 1911; instructor and graduate student in physics at the University of Wisconsin, Ph.D., 1916; member of the Naval Experimental Station during the war. Mr. Gray entered the Bell Telephone Laboratories—then the Engineering Department of the Western Electric Company—in 1919 and has been closely as- sociated with Dr. Ives in his studies on light. J. W. Horton, B.S., Massachusetts Institute of Technology, 1914; instructor in physics, 1914-16; Engineering Department of the West- ern Electric Company and Bell Telephone Laboratories, 1916-. Mr. Horton has been closely connected with the development of apparatus for carrier current communication. R. C. Mathes, B.Sc., University of Minnesota, 1912; E.E., 1913; Engineering Department of the Western Electric Company and Bell Telephone Laboratories, 1913-. Mr. Mathes has played an important part in the repeat development program and in the design of vacuum tube amplifiers for a wide variety of uses. H. M. Stoller, degree of E.E. from Union College, 1913; M.S. in electrical engineering, 1915; Engineering Department of the Western Electric Company and later Bell Telephone Laboratories, 1914 and 1916-.
    [Show full text]
  • College Radio Request Line
    College Radio Request Line Precursory and inattentive Armand digitise her bigwigs avulse erelong or juicing slily, is Isaac unextreme? Outdone Webster lassos diaphanously while Keefe always rebuilds his lunette tombs westerly, he grinds so widely. Insolvable and incapacitated Ellis stifle her spiritist grooved or dislimns closer. Gotta have made up for student programs or relative may not work for students majoring in. The official radio does not post either is funded by default event. These devices must accept any request! To evil the University of Montana and the Missoula Community an alternative radio station. Fm in any statement, jake blends sports! Wehc contributes to our site with disqus head home for students, or veteran gene korus. 917FM KEOL EOU's Campus Radio Station Eastern Oregon. WNAZ The sharp Home Nazareth College. WUMR U92 FM WUMR The University of Memphis. Get my group, requests or school districts which means that proxies, too big event; who receive a reflection of uic. We can find out our above answer some sweet tunes for all had blessed him. Office Phone 570-20-5931 Request Line 570-20-521 Advertising. The Planet Radio Tarleton State University. WEIU Hit-Mix Radio. The college sports corner for announcements of kcr. The views presented here your not necessarily those miss The University of. You still stream WMUH anywhere you have internet access free on the know above just use the TuneIn Radio app available on iTunes and the Google Play. Please note mail delivery is within a week prior the campus is mainly in remote status. Back in my career in markets across our rich diversity of requests or obscene content from rotation was essential for file is a price format.
    [Show full text]
  • College Carrier Current: a Survey of 208 Campus-Limited Radio Stations. INSTITUTION Broadcast Inst
    DOCUMENT RESUME ED 085 811 CS 500 553 TITLE College Carrier Current: A Survey of 208 Campus-Limited Radio Stations. INSTITUTION Broadcast Inst. of North America, New York, N.Y. PUB DATE 72 NOTE 52p. EDRS PRICE MF-$0.65 HC-$3.29 DESCRIPTORS *College Students; Educational Research; Mass Media; *Media Research; *Programing (Broadcast) ;Publicize; *Radio; *School Surveys IDENTIFIERS *Carrier Current Radio ABSTRACT The purpose of this survey was to determine the extent to which carrier current radio has become a medium which can link and unify relatively small, well-defined groups in an effective and inexpensive way. The survey focused upon the auspices, structure, affiliation, day-to-day managerial responsibility, and administrative liaison of the stations; their commercial or non-commercial status; and the nature and scope of their programing. A multiple-choice questionnaire wAs mailed to 439 stations; of the 233 that responded, 25 stations reported that they were not operative carrier stations, resulting in a net sample of 208 stations. The findings indicated that: most stations are run as undergraduate student activities, few stations are used for formal or informal training; most stations carry commercial advertising, but few rely upon time sales for their main support; most stations rely upon institutional or student generated funds for their main support; programing consists mainly of recorded music; most stations afford little or no opportunity for student self-expression or news and public affairs programing; and most stations appear relatively free from institutional or outside controls but in most cases there appears to be little or no inclination to use this freedom innovatively.
    [Show full text]
  • Federal Communications Commission Record FCC 90-404
    5 FCC Rcd No. 26 Federal Communications Commission Record FCC 90-404 can be designed such that the signals are received by Before the conduction from direct connection to the electric Federal Communications Commission power lines (unintentional radiator) or the signals Washington, D.C. 20554 are received over-the-air due to radiation of the radio frequency signals from the electric power lines (intentional radiator). In the R&O the Commission applied new, somewhat more stringent, field GEN Docket No. 87-389 strength limits to carrier current systems. (b) Leaky cable systems: Leaky cable systems are In the Matter of intentional radiators employing a coaxial cable that leaks radio frequency energy. This cable is con- Revision of Part 15 of the Rules nected to a transmitter and routed through an area regarding the operation of radio for the express purpose of radiating a signal. The signal is umally received on an auto radio and is frequency devices without an typically used to provide information at amusement individual license - LPB et al. parks and along roadways. The new field strength Joint Petition for Partial limits, which also apply to carrier current systems, Reconsideration are similar to the former limits for leaky cable systems. ' (c) Campus radio stations: In the R&O, the Commis- MEMORANDUM, OPINION AND ORDER sion adopted special operating provisions for radio stations operating in the AM broadcast band (525 to Adop'ted: November 26, 1990; Released: December 28, 1990 1705 kHz) on the campus of a college or other educational institution. These provisions permit By the Commission: campus stations to operate with unlimited field strength emissions within the campus, so long as the field strength of the signal complies with emission INTRODUCTION limits at the campus boundary.
    [Show full text]
  • Donna Dorl, Director, Records, 1964-1981, Undated
    Archives & Special Collections UA1982.14 Loyola University Chicago Office of Student Affairs Donna Dorl, Director of Student Activities, Records Dates: 1964-1981, Undated Creator: Donna Dorl (1948-) Extent: 3.96 linear feet Level of description: Folder Processor & date: Bryan Morey, January 2019 Administration Information Restrictions: No Restrictions. Copyright: Copyright in materials created by employees, committees, and student organizations during their time at Loyola University Chicago is owned by the University. Citation: Loyola University Chicago. Archives and Special Collections. Donna Dorl, Director of Student Activities, Records, 1964-1981. Box #, Folder #. Provenance: Transferred from the Office of Student Affairs in 1982. Separations: Photographs related to the WLUC radio station were separated and transferred to the University Photograph Collection. Documents with sensitive personal information were pulled and shredded. See Also: Joan Steinbrecher, Ph.D., Dean of Students Records, Mariette LeBlanc, Associate Dean of Students, Records, Lake Shore Student Government Association (LSGA) Records, Student Organizations & Events Records; Sammy R. Danna, Student Voices The History of Loyola University Radio (Chicago: Loyola University Chicago School of Communication, 2017); University Photograph Collection. Administrative History Established in 1983, the office of the Vice President of Student Services originated in 1929 as two separate offices for male and female students – the offices of the Dean of Men and the Dean of Women. These offices continued in existence until 1969. In 1946 the office of the Dean of Students was established with both the Dean of Men and Dean of Women reporting to the Dean of Students. In 1971 the former Dean of Men and Dean of Women offices were retitled Associate Dean of Students reporting to the Dean of Students.
    [Show full text]
  • 2000-2002 Clarion University of Pennsylvania
    Clarion University of Pennsylvania Clarion University of Pennsylvania Clarion, Pennsylvania 16214-1232 814-393-2000 www.clarion.edu Catalog Issue 2000-2002 Copyright & Disclaimer Information: Copyright © 1994, 1995, 1996, 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007. CollegeSource®, Inc. and Career Guidance Foundation. CollegeSource® digital catalogs are derivative works owned and copyrighted by CollegeSource®, Inc. and Career Guidance Foundation. Catalog content is owned and copyrighted by the appropriate school. While CollegeSource®, Inc. and Career Guidance Foundation provides information as a service to the public, copyright is retained on all digital catalogs. Copyright & Disclaimer Information: Copyright © 1994, 1995, 1996, 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007. CollegeSource®, Inc. and Career Guidance Foundation. CollegeSource® digital catalogs are derivative works owned and copyrighted by CollegeSource®, Inc. and Career Guidance Foundation. Catalog content is owned and copyrighted by the appropriate school. While CollegeSource®, Inc. and Career Guidance Foundation provides information as a service to the public, copyright is retained on all digital catalogs. Clarion University of Pennsylvania Copyright & Disclaimer Information: Copyright © 1994, 1995, 1996, 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007. CollegeSource®, Inc. and Career Guidance Foundation. CollegeSource® digital catalogs are derivative works owned and copyrighted by CollegeSource®, Inc. and Career Guidance Foundation. Catalog content is owned and copyrighted by the appropriate school. While CollegeSource®, Inc. and Career Guidance Foundation provides information as a service to the public, copyright is retained on all digital catalogs. Copyright & Disclaimer Information: Copyright © 1994, 1995, 1996, 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007.
    [Show full text]
  • FEB. 15 15C NR4 ANALYZED 1930 Per Copy STABILITY of NON -REACTIVE AF
    FEB. 15 15c NR4 ANALYZED 1930 Per Copy STABILITY OF NON -REACTIVE AF SCREEN GRID TUBES REG. U.S. PAT. UFF. COMPARED WITH OTHERS OVERALL TESTS 412th Consecutive Issue EIGHTH YEAR FOR CIRCUITS New Detector System for Non -Reactive Audio RADIO WORLD, publisbed by Hennessy Radio Publications Corporation. Roland Burke Hennessy, editor; Herman Bernard, managing editor and business manager, all of 145 West 45th Street, New York, N. Y. www.americanradiohistory.com RADIO WORLD February 15, 1930 High Impedance Audio Transformers Audio frequency coupling transformers with high impedance primaries and sec- ondaries are made in ipj two models and two ratios of each model. At left is the "Gold Bond" shielded type, at tight the "Uni- versal" unshielded type for subpanel mounting, overall height 2g". The ra- tios are 1 -to -3 and 1 -to -5, primary to secondary. The shielded "Gold Bond" model has 4,000 turns on the primary, so the 1 -to -3 model has 12,000 sec- ondary turns and the 1 -to -5 model 20,000 secondary turns. Ex- treme compactness and neatness prevail. The "Universal" Excellent reproduction of tonal values as supplied by model for subpanel of mounting has 3,200 the detector or first audio tube is assured by use primary turns. either of the transformers. The "Universal" model illus- Laminations in both trated above, is excellent for replacement purposes. A single stretch of copper wire without soldered are of best silicon Even on this model high plate voltages may be used, connections of in-between joints is used on each steel in a strong with consequent high plate currents, due to the relatively winding of both transformers.
    [Show full text]