Long-Wave and Medium-Wave Propagation
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7400.2D Procedures for Handling • Airspace Matters •
U.S. Department of Transportation Federal Aviation • Administration 7400.2D Procedures for Handling • Airspace Matters • ·'" ..... "", • Distribution: ZAT-740 (ALL); September 16, 1993 Initiated by ATP-200 RECORD OF CHANGES DIRECTIVE NO. 7400.2D CHANGE SUPPLEMENTS CH,oNGE SUPPLEMENTS TO OPTIONAL TO OPTIONAL BASIC BASIC • .. .. • 1---. • FAA Form 132~5 (6-80) USE PREVIOUS EDITION 9/16/93 7400.2D • PROCEDURES FOR HANDLING AIRSPACE MATTERS 7400.2D FOREWORD • This Order shall be used by all personnel in the joint administration of the airspace program. The guidance and procedures herein incorporate into one publication as many orders, notices and di rectives of the affected services as possible. This order consists of 8 parts and incorporates all re quired changes due to the Airspace Reclassification Rule effective September 16, 1993. • ~l~£~ Associate Administrator for Air Traffic :u..~ Anthony J. erick (AVR) \UAiIAmWd Associat~ Administrator for AssociDt~ Administrator Regulation & Certification for Airway Facilities • 9/16/93 7400.2D TABLE OF CONTENTS • [Bracketed numbers represent the numbering system in Order 7400.2C] PART I. GENERALPROCEDURES Chapter 1. GENERAL Section 1. INTRODUCTION Page 1-1 Purpose/Application {1 000] . 1-1-1 1-2 Effective Date {1001] . 1-1-1 1-3 Cancellation {1002] . 1-1-1 1-4 Change Authority {1003] .. 1-1-1 1-5 Other Responsibilities {1004] . 1-1-1 1-6 Structural Format {1 005] . 1-1-1 1-7 Policy {1006] .. 1-1-1 1-8 Authority and Applicability {1007] . 1-1-1 1-9 FAR References {1008] . 1-1-1 1-10 Executive Order 10854 {1009] . 1-1-2 1-11 Word Usage {1010] . -
Signal Issue 37
Signal Issue 37 Tricks of the Trade Dave Porter G4OYX and Alan Beech G1BXG By 25th September 1965, Radio 390 was on the air and 31st December 2015 marks the fiftieth anniversary of the start of the offshore station Radio Scotland. The only remaining station to launch with RCA 10 kW Ampliphase transmitters was Radio 270 from 4th June 1966, on-air some three months later than originally planned. Member’s contribution understood that, whilst CE was used to these T-K arrangements, mainly for Government contracts, the need After reading the last three ToTT, VMARS Member Tony to effect a quick turn-around with minimal delays was not Rock G3KTR/AD1X contacted the author (DP) with the quite their norm. With time slipping by, the decision was following information on the 1965 build of Radio Scotland. made to leave the USA without the systems being totally commissioned and to complete en-route. Also, during this Tony writes; I read with interest the article you and Alan trip, it was discovered that one of the planned operating put together on Ampliphase transmitters. In the mid-1960s frequencies, namely 650 kHz, was actually occupied in the I was working out of the RCA Broadcast & UK by a certain high-power station on 647 kHz, the Communications Division at Sunbury-on-Thames. At this 150 kW BBC Third Programme. It was understood that an time RCA had sold several transmitters to offshore ‘pirate’ early ‘recce’ by the Americans to the UK to check for ‘spare radio stations. While Marconi and other European channels’ resulted in a monitoring time when the Third companies could be subjected to sanctions by the Programme was not scheduled on air. -
VHF and UHF Signal Characteristics Observed on a Long Knife-Edge Diffraction Path A
JOURNAL OF RESEARCH of the National Bureau of Standards- D. Radio Propagatior. Vol. 65D, No. 5, September- Odober 1961 VHF and UHF Signal Characteristics Observed on a Long Knife-Edge Diffraction Path A. P. Barsis and R. S. Kirby (R eceived April 6, 1961) Contribution from Central Radio Propagation Laboratory, National Bureau of Standards, Boulder, Colo. During 1959 and 1960 long-term transmission loss measurements were performed over a 223 kilom eter path in Eastern Colorado using frequencies of 100 and 751 megacycles per second. This path intersects P ikes P eak which forms a knife-edge type obstacle visible from both terminals. The transmission loss measurements have been analyzed in terms of diurnal a nd seaso nal variations in hourly medians and in instan taneous levels. As expected, results show t hat the long-term fading range is substantially less t han expected for t ropospheric seatter paths of comparable length. T ransmission loss levels were in general agreem ent wi t h predicted k ni fe-edge d iffraction propagation when a ll owance is made for rounding of t he knife edge. A technique for est imatin g long-term fading ra nges is presented a nd t he res ults are in good agreement with observations. Short-term variations in some case resemble t he space-wave fadeo uts commonly observed on within- the-horizon paths, a lthough other phe nomena may contribute to t he fadin g. Since t he foreground telTain was rough there was no evidence of direct a nd grou nd-refl ected lobe structure. -
Capacity of Flat and Freq.-Selective Fading Channels Linear Digital Modulation Review
Lecture 8 - EE 359: Wireless Communications - Winter 2020 Capacity of Flat and Freq.-Selective Fading Channels Linear Digital Modulation Review Lecture Outline • Channel Inversion with Fixed Rate Transmission • Comparison of Fading Channel Capacity under Different Schemes • Capacity of Frequency Selective Fading Channels • Review of Linear Digital Modulation • Performance of Linear Modulation in AWGN 1. Channel Inversion with Fixed Rate Transmission • Suboptimal transmission strategy where fading is inverted to maintain constant re- ceived SNR. • Simplifies system design and is used in CDMA systems for power control. • Capacity with channel inversion greatly reduced over that with optimal adaptation (capacity equals zero in Rayleigh fading). • Truncated inversion: performance greatly improved by inverting above a cutoff γ0. 2. Comparison of Fading Channel Capacity under Different Schemes: • Fading generally decreases channel capacity. • Rate/power adaptation have similar capacity as rate adaptation alone. • Rate adaptation alone has same capacity as no adaptation (RX CSI only) but rate adaptation is more practical due to complexity of ML decoding over long blocklengths that experience all fading values. This ML decoding is necesssary to achieve capacity in the RX CSI only case. • Truncated channel inversion is more practical than rate adaptation, with significant capacity gain over full channel inversion, which has zero capacity in Rayleigh fading. 3. Capacity of Frequency Selective Fading Channels • Capacity for time-invariant frequency-selective fading channels is a \water-filling” of power over frequency. • For time-varying ISI channels, capacity is unknown in general. Approximate by di- viding up the bandwidth subbands of width equal to the coherence bandwidth (same premise as multicarrier modulation) with independent fading in each subband. -
Distortion Exponent of Parallel Fading Channels
Distortion Exponent of Parallel Fading Channels Deniz Gunduz, Elza Erkip Department of Electrical and Computer Engineering, Polytechnic University, Brooklyn, NY 11201, USA [email protected], [email protected] Abstract— We consider the end-to-end distortion achieved by the fading process. Lack of channel state information at the transmitting a continuous amplitude source over M parallel, transmitter prevents the design of a channel code that achieves independent quasi-static fading channels. We analyze the high the instantaneous channel capacity and requires a code that SNR expected distortion behavior characterized by the distortion exponent. We first give an upper bound for the distortion performs well on the average. We aim to design a joint source- exponent in terms of the bandwidth ratio between the channel channel code that achieves the minimum expected end-to-end and the source assuming the availability of the channel state distortion. Our main focus is the high SNR behavior of this information at the transmitter. Then we propose joint source- expected distortion (ED). This behavior is characterized by the channel coding schemes based on layered source coding and distortion exponent denoted by ¢ and defined as multiple rate channel coding. We show that the upper bound is tight for large and small bandwidth ratios. For the rest, we log ED provide the best known distortion exponents in the literature. ¢ = ¡ lim : (1) SNR!1 log SNR By suitably scaling the bandwidth ratio, our results would also apply to block fading channels. When we consider digital transmission strategies that first compress the source and then transmit over the channel at I. -
Implementation Considerations for the Introduction and Transition to Digital Terrestrial Sound and Multimedia Broadcasting
Report ITU-R BS.2384-0 (07/2015) Implementation considerations for the introduction and transition to digital terrestrial sound and multimedia broadcasting BS Series Broadcasting service (sound) ii Rep. ITU-R BS.2384-0 Foreword The role of the Radiocommunication Sector is to ensure the rational, equitable, efficient and economical use of the radio- frequency spectrum by all radiocommunication services, including satellite services, and carry out studies without limit of frequency range on the basis of which Recommendations are adopted. The regulatory and policy functions of the Radiocommunication Sector are performed by World and Regional Radiocommunication Conferences and Radiocommunication Assemblies supported by Study Groups. Policy on Intellectual Property Right (IPR) ITU-R policy on IPR is described in the Common Patent Policy for ITU-T/ITU-R/ISO/IEC referenced in Annex 1 of Resolution ITU-R 1. Forms to be used for the submission of patent statements and licensing declarations by patent holders are available from http://www.itu.int/ITU-R/go/patents/en where the Guidelines for Implementation of the Common Patent Policy for ITU-T/ITU-R/ISO/IEC and the ITU-R patent information database can also be found. Series of ITU-R Reports (Also available online at http://www.itu.int/publ/R-REP/en) Series Title BO Satellite delivery BR Recording for production, archival and play-out; film for television BS Broadcasting service (sound) BT Broadcasting service (television) F Fixed service M Mobile, radiodetermination, amateur and related satellite services P Radiowave propagation RA Radio astronomy RS Remote sensing systems S Fixed-satellite service SA Space applications and meteorology SF Frequency sharing and coordination between fixed-satellite and fixed service systems SM Spectrum management Note: This ITU-R Report was approved in English by the Study Group under the procedure detailed in Resolution ITU-R 1. -
Frequency Modulation
Unguided Media and Matched Filter After this lecture, you will be able to – describe the physical and transmission characteristics of various unguided media Example ? B.1 Unguided media Guided to unguided – Transmission • the signal is guided to an antenna via a guided medium • antenna radiates electromagnetic energy into the medium – Reception • antenna picks up electromagnetic waves from the surrounding medium. – Example • a voice signal from a telephone network is guided via a twisted pair to a base station of mobile telephone network • the antennas of the base station radiates electromagnetic energy into the air • the antenna of the mobile phone handset picks up electromagnetic waves B.2 Directional and Omnidirectional Directional – the transmitting antennaHow puts to out focus a focused an electromagnetic beam electromagnetic wave ? – the transmitting and receiving antennas must be aligned – Example • Satellite communication systems • For a satellite located at 35784km above the ground, a 1° beam covers 1962km2 B.3 Directional and Omnidirectional Omnidirectional – the transmitted signal spreads out in all directions and can be received by many antennas. – In general, the higher the frequency of a signal, the more it is possible to focus it into a directional beam – Example • mobile communication systems • radio broadcasting B.4 Operating freqeuncies Microwave – Frequencies in the range of about 30 MHz to 40 GHz are referred to as microwave frequencies – 2 GHz to 40 GHz • wavelength in air is 0.75cm to 15cm ¾wavelength = velocity / frequency • highly directional beams are possible • suitable for point-to-point transmission – 30 MHz to 1 GHz • suitable for omnidirectional applications B.5 Operating freqeuncies B.6 Terrestrial Microwave Physical description – limited to line-of-sight transmission. -
Low Frequency Converter.Pdf
Find out whatk happening below the A M-broadcast band with our low-frequency converter: WILLIAM SHEETS AND RUDOLF F. GRAF simply adding 1 MHz to all received signals. Connect our converter to any communications receiver, or AM-broad- cast radio for that matter, and bingo--you have a longwave receiver. Radio calibration is unnecessary because signals are received at the AM-radio's dial setting, plus 1 MHz. A 100-kHz signal is received at 1100 kHz, a 335-kHz signal at 1335 kHz, etc., just drop the first digit to read the longwave frequency. THE FREQUENCY RANGE JUST BELOW THE AM-BROAD- One problem at low frequencies is man-made noise; cast band (from 10 kHz to 550 kHz) has been clearly many of our everyday devices and appliances are notorious omitted from most communication receivers. How come? in that regard. Motors, fluorescent lighting, light dim- It appears that the extra coil sets, increased assembly mers, computes, TV-receiver sweep radiation, and many costs, and additional RF circuitry has not justified the small household digital devices generate "hash" in the inclusion of the low-frequency band. But that doesn't have spectrum below 550 kHz. Fortunately, most noise is car- to stop you from sneaking a peek at the band "down- ried chiefly on power lines, and doesn't radiate very far. under." Among the signals you'll find below 550 kHz are One misconception is that tremendous antennas are maritime mobile, distress, radio beacons, aircraft weather, needed for longwave reception. It's easy to understand European longwave-AM broadcast, and point-to-point why someone night think that way. -
On Routing in Random Rayleigh Fading Networks Martin Haenggi, Senior Member, IEEE
IEEE TRANSACTIONS ON WIRELESS COMMUNICATIONS, VOL. 4, NO. 4, JULY 2005 1553 On Routing in Random Rayleigh Fading Networks Martin Haenggi, Senior Member, IEEE Abstract—This paper addresses the routing problem for large loss probabilities increase with the number of hops (unless the wireless networks of randomly distributed nodes with Rayleigh transmit power is adapted). fading channels. First, we establish that the distances between To overcome some of these limitations of the “disk model,” neighboring nodes in a Poisson point process follow a generalized Rayleigh distribution. Based on this result, it is then shown that, we employ a simple Rayleigh fading link model that relates given an end-to-end packet delivery probability (as a quality of transmit power, large-scale path loss, and the success of a service requirement), the energy benefits of routing over many transmission. The end-to-end packet delivery probability over short hops are significantly smaller than for deterministic network a multihop route is the product of the link-level reception models that are based on the geometric disk abstraction. If the probabilities. permissible delay for short-hop routing and long-hop routing is the same, it turns out that routing over fewer but longer hops may While fading has been considered in the context of packet even outperform nearest-neighbor routing, in particular for high networks [16], [17], its impact on the network (and higher) end-to-end delivery probabilities. layers is largely an open problem. This paper attempts to shed Index Terms—Ad hoc networks, communication systems, fading some light on this cross-layer issue by analyzing the perfor- channels, Poisson processes, probability, routing. -
The H3K9 Methylation Writer SETDB1 and Its Reader MPP8 Cooperate to Silence Satellite DNA Repeats in Mouse Embryonic Stem Cells
G C A T T A C G G C A T genes Article The H3K9 Methylation Writer SETDB1 and Its Reader MPP8 Cooperate to Silence Satellite DNA Repeats in Mouse Embryonic Stem Cells 1,2,3,4 1 1, 1 Paola Cruz-Tapias , Philippe Robin , Julien Pontis y, Laurence Del Maestro and Slimane Ait-Si-Ali 1,* 1 Epigenetics and Cell Fate (EDC), Centre National de la Recherche Scientifique (CNRS), Université de Paris, Université Paris Diderot, F-75013 Paris, France; [email protected] (P.C.-T.); [email protected] (P.R.); julien.pontis@epfl.ch (J.P.); [email protected] (L.D.M.) 2 Faculty of Natural Sciences and Mathematics, Universidad del Rosario, Bogotá 111221, Colombia 3 School of Medicine and Health Sciences, Universidad del Rosario, Bogotá 111221, Colombia 4 Doctoral Program in Biomedical and Biological Sciences, Universidad del Rosario, Bogotá 111221, Colombia * Correspondence: [email protected]; Tel.: +33-(0)1-5727-8919 Current: Ecole Polytechnique Fédérale de Lausanne (EPFL), SV LVG Station 19, 1015 Lausanne, Switzerland. y Received: 25 August 2019; Accepted: 24 September 2019; Published: 25 September 2019 Abstract: SETDB1 (SET Domain Bifurcated histone lysine methyltransferase 1) is a key lysine methyltransferase (KMT) required in embryonic stem cells (ESCs), where it silences transposable elements and DNA repeats via histone H3 lysine 9 tri-methylation (H3K9me3), independently of DNA methylation. The H3K9 methylation reader M-Phase Phosphoprotein 8 (MPP8) is highly expressed in ESCs and germline cells. Although evidence of a cooperation between H3K9 KMTs and MPP8 in committed cells has emerged, the interplay between H3K9 methylation writers and MPP8 in ESCs remains elusive. -
Worldwide Availability of Maritime Medium-Frequency Radio Infrastructure for R-Mode-Supported Navigation
Journal of Marine Science and Engineering Article Worldwide Availability of Maritime Medium-Frequency Radio Infrastructure for R-Mode-Supported Navigation Paul Koch * and Stefan Gewies German Aerospace Center (DLR), Institute of Communications and Navigation, Kalkhorstweg 53, 17235 Neustrelitz, Germany; [email protected] * Correspondence: [email protected] Received: 10 January 2020; Accepted: 11 March 2020; Published: 18 March 2020 Abstract: The Ranging Mode (R-Mode), a maritime terrestrial navigation system under development, is a promising approach to increase the resilient provision of position, navigation and timing (PNT) information for bridge instruments, which rely on Global Navigation Satellite Systems (GNSS). The R-Mode utilizes existing maritime radio infrastructure such as marine radio beacons, which support maritime traffic with more reliable and accurate PNT data in areas with challenging conditions. This paper analyzes the potential service, which the R-Mode could provide to the mariner if worldwide radio beacons were upgraded to broadcast R-Mode signals. The authors assumed for this study that the R-Mode is available in the service area of the 357 operational radio beacons. The comparison with the maritime traffic, which was generated from a one-day worldwide Automatic Identification System (AIS) Class A dataset, showed that on average, 67% of ships would operate in a global R-Mode service area, 40% of ships would see at least three and 25% of ships would see at least four radio beacons at a time. This means that R-Mode would support 25% to 40% of all ships with position and 67% of all ships with PNT integrity information. -
Kahn Communications, Inc. 425 Merrick Avenue Westbury, New York 11590 (516) 2222221
KAHN COMMUNICATIONS, INC. 425 MERRICK AVENUE WESTBURY, NEW YORK 11590 (516) 2222221 THE "WGAS EFFECT" AND THE FUTURE OF AM RADIO In the history of broadcasting a number of "Effects" have dramatically impacted on broadcasting. For example, the "Capture Effect" and the "Multipath Effect" of FM, and earlier "Radio Luxemburg Effect" helped shape broadcasting history. More recently, "Clicks and Pops", "Platform Motion", and "Rain Noise" have influenced the path of AM Stereo. Remember when the Magnavox system was selected by the FCC as the standard in 1980 and the "Click and Pop" effect was discovered. By 1982 it became clear that this "Click and Pop" problem made it essential that the FCC revisit its decision. There is now a new phenomenon which we propose to name the "WGAS Effect" because it was first described in the "Open Mike" section of the September 7, 1987 issue of "Broadcasting" by Mr. Glenn Mace, President of WGAS, South Gastonia, North Carolina. It is essential that all AM broadcasters carefully read this short letter because the very future of AM radio may depend upon the industries knowledge of its contents. It should be stressed that WGAS does not, and cannot, endorse our stereo system as they have never used it. But, nevertheless, we are most appreciative that Mr. Mace has taken the time and effort to make his observations public on this important matter. More will follow re the "WGAS Effect" and how it impacts on all stations, large and small, which must serve listeners in their 25 my/meter contour and beyond. age.