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WWVB: a Half Century of Delivering Accurate Frequency and Time by Radio
Volume 119 (2014) http://dx.doi.org/10.6028/jres.119.004 Journal of Research of the National Institute of Standards and Technology WWVB: A Half Century of Delivering Accurate Frequency and Time by Radio Michael A. Lombardi and Glenn K. Nelson National Institute of Standards and Technology, Boulder, CO 80305 [email protected] [email protected] In commemoration of its 50th anniversary of broadcasting from Fort Collins, Colorado, this paper provides a history of the National Institute of Standards and Technology (NIST) radio station WWVB. The narrative describes the evolution of the station, from its origins as a source of standard frequency, to its current role as the source of time-of-day synchronization for many millions of radio controlled clocks. Key words: broadcasting; frequency; radio; standards; time. Accepted: February 26, 2014 Published: March 12, 2014 http://dx.doi.org/10.6028/jres.119.004 1. Introduction NIST radio station WWVB, which today serves as the synchronization source for tens of millions of radio controlled clocks, began operation from its present location near Fort Collins, Colorado at 0 hours, 0 minutes Universal Time on July 5, 1963. Thus, the year 2013 marked the station’s 50th anniversary, a half century of delivering frequency and time signals referenced to the national standard to the United States public. One of the best known and most widely used measurement services provided by the U. S. government, WWVB has spanned and survived numerous technological eras. Based on technology that was already mature and well established when the station began broadcasting in 1963, WWVB later benefitted from the miniaturization of electronics and the advent of the microprocessor, which made low cost radio controlled clocks possible that would work indoors. -
EHC 238 Front Pages Final.Fm
This report contains the collective views of an international group of experts and does not necessarily represent the decisions or the stated policy of the International Commission of Non- Ionizing Radiation Protection, the International Labour Organization, or the World Health Organization. Environmental Health Criteria 238 EXTREMELY LOW FREQUENCY FIELDS Published under the joint sponsorship of the International Labour Organization, the International Commission on Non-Ionizing Radiation Protection, and the World Health Organization. WHO Library Cataloguing-in-Publication Data Extremely low frequency fields. (Environmental health criteria ; 238) 1.Electromagnetic fields. 2.Radiation effects. 3.Risk assessment. 4.Envi- ronmental exposure. I.World Health Organization. II.Inter-Organization Programme for the Sound Management of Chemicals. III.Series. ISBN 978 92 4 157238 5 (NLM classification: QT 34) ISSN 0250-863X © World Health Organization 2007 All rights reserved. Publications of the World Health Organization can be obtained from WHO Press, World Health Organization, 20 Avenue Appia, 1211 Geneva 27, Switzerland (tel.: +41 22 791 3264; fax: +41 22 791 4857; e- mail: [email protected]). Requests for permission to reproduce or translate WHO publications – whether for sale or for noncommercial distribution – should be addressed to WHO Press, at the above address (fax: +41 22 791 4806; e-mail: [email protected]). The designations employed and the presentation of the material in this publication do not imply the expression of any opinion whatsoever on the part of the World Health Organization concerning the legal status of any country, territory, city or area or of its authorities, or concerning the delimitation of its frontiers or boundaries. -
A Century of WWV
Volume 124, Article No. 124025 (2019) https://doi.org/10.6028/jres.124.025 Journal of Research of the National Institute of Standards and Technology A Century of WWV Glenn K. Nelson National Institute of Standards and Technology, Radio Station WWV, Fort Collins, CO 80524, USA [email protected] WWV was established as a radio station on October 1, 1919, with the issuance of the call letters by the U.S. Department of Commerce. This paper will observe the upcoming 100th anniversary of that event by exploring the events leading to the founding of WWV, the various early experiments and broadcasts, its official debut as a service of the National Bureau of Standards, and its role in frequency and time dissemination over the past century. Key words: broadcasting; frequency; radio; standards; time. Accepted: September 6, 2019 Published: September 24, 2019 https://doi.org/10.6028/jres.124.025 1. Introduction WWV is the high-frequency radio broadcast service that disseminates time and frequency information from the National Institute of Standards and Technology (NIST), part of the U.S. Department of Commerce. WWV has been performing this service since the early 1920s, and, in 2019, it is celebrating the 100th anniversary of the issuance of its call sign. 2. Radio Pioneers Other radio transmissions predate WWV by decades. Guglielmo Marconi and others were conducting radio research in the late 1890s, and in 1901, Marconi claimed to have received a message sent across the Atlantic Ocean, the letter “S” in telegraphic code [1]. Radio was called “wireless telegraphy” in those days and was, if not commonplace, viewed as an emerging technology. -
What Is Rf? It's Like Magic
Originally appeared in the December 2011 issue of Communications Technology. WHAT IS RF? IT’S LIKE MAGIC By RON HRANAC The cable industry has, since the very first systems in the late 1940s, embraced and been based on radio frequency (RF) technology. These days, we’ve also embraced the digital world — and a subset of digital technology called Internet protocol (IP) — but RF still is needed in most cable networks to transport digital data to and from devices in our subscribers’ homes. The answer to the question in the title of this month’s column is far more complicated than it seems initially. A good place to start is with an explanation of “R” and “F.” What’s radio frequency? Here’s one high-level perspective: It’s that portion of the electromagnetic spectrum from a few kilohertz to about 300 gigahertz. The radio-frequency part of the electromagnetic spectrum is further broken down into two chunks: radio waves and microwaves. Some references define radio waves as those with a frequency starting at about 3 kHz (the beginning of the very low frequency [VLF] band) and extending to 300 MHz (the beginning of the ultra high frequency [UHF] band), with microwaves covering roughly 300 MHz to 300 GHz. The latter is the beginning of the far infrared (FIR) portion of the electromagnetic spectrum. Other references have microwaves starting at frequencies higher than 300 MHz; indeed, many RF engineers consider the microwave spectrum to be higher than about 1 GHz. Radio frequency also can be defined as a rate of oscillation within the 3 kHz to 300 GHz range (more on this in a moment). -
Very-Low-Frequency Radio Propagation in the Ionosphere
JOURNAL OF RESEARCH of the National Bureau of Standards-D. Radio Propagation Vol. 66D, No. 6, November- December 1962 Very-Low-Frequency Radio Propagation In the Ionosphere Daniel W. Swift Contribution from Research and Advanced Development Division, Avco Corporation, Wilmington, Mass. (R eceived April 27, 1962 ; revised June 5, 1962) Equations describing the propagation of radio waves in a horizontally stratified a niso tropic ionosphere were developed by considering the limit.ing case of a la rge number of in finitesimall y t hin slabs of constant electron density a nd collision frequency. The quasi longitudin al approximation was used. The propagation equations appeared as four co upled first-order linear differential equations, co upled by gradients in electron density and collision frequency. The quasi-longit udina l a pproxima tion permitted use of particul a rl y s imple forms for t he co upling coe ffi cients, t hese forms bein g a menable to simple analysis. Coupling between two ordinary or two extraordinary modes was found to be co nsid erably stronger than cross coupling between ordinary a nd extraordinary mode . Cross couplin g was related to the rate of change of the direction of the phase normal. It was found that the re fl ection of VLF radio waves from t he daytime ionosphere is relatively insensitive to t he angle of incidence on the ionosphere except for highly oblique propagation. "Vhistler penetration was a lso found to be insensitive to the angle of in cid ence on the ionosphere. 1. Introduction In this report, we shall consider the full-'wave solutions for a very low frequency radio wave propagating obliquely into a horizontally stratified ionosphere. -
KHF 950/990 HF Communications Transceiver PILOT’S GUIDE and DIRECTORY of HF SERVICES
KHF 950/990 HF Communications Transceiver PILOT’S GUIDE AND DIRECTORY OF HF SERVICES A Table of Contents INTRODUCTION KHF 950/990 COMMUNICATIONS TRANSCEIVER . .I SECTION I CHARACTERISTICS OF HF SSB WITH ALE . .1-1 ACRONYMS AND DEFINITIONS . .1-1 REFERENCES . .1-1 HF SSB COMMUNICATIONS . .1-1 FREQUENCY . .1-2 SKYWAVE PROPAGATION . .1-3 WHY SINGLE SIDEBAND IS IMPORTANT . .1-9 AMPLITUDE MODULATION (AM) . .1-9 SINGLE SIDEBAND OPERATION . .1-10 SINGLE SIDEBAND (SSB) . .1-10 SUPPRESSED CARRIER VS. REDUCED CARRIER . .1-10 SIMPLEX & SEMI-DUPLEX OPERATION . .1-11 AUTOMATIC LINK ESTABLISHMENT (ALE) . .1-11 FUNCTIONS OF HF RADIO AUTOMATION . .1-11 ALE ASSURES BEST COMM LINK AUTOMATICALLY . .1-12 SECTION II KHF 950/990 SYSTEM DESCRIPTION. .2-1 KCU 1051 CONTROL DISPLAY UNIT . .2-1 KFS 594 CONTROL DISPLAY UNIT . .2-3 KCU 951 CONTROL DISPLAY UNIT . .2-5 KHF 950 REMOTE UNITS . .2-6 KAC 952 POWER AMPLIFIER/ANT COUPLER .2-6 KTR 953 RECEIVER/EXITER . .2-7 ADDITIONAL KHF 950 INSTALLATION OPTIONS .2-8 SINGLE KHF 950 SYSTEM CONFIGURATION .2-9 KHF 990 REMOTE UNITS . .2-10 KAC 992 PROBE/ANTENNA COUPLER . .2-10 KTR 993 RECEIVER/EXITER . .2-11 SINGLE KHF 990 SYSTEM CONFIGURATION . .2-12 Rev. 0 Dec/96 KHF 950/990 Pilots Guide Toc-1 Table of Contents SECTION III OPERATING THE KHF 950/990 . .3-1 KHF 950/990 GENERAL OPERATING INFORMATION . .3-1 PREFLIGHT INSPECTION . .3-1 ANTENNA TUNING . .3-2 FAULT INDICATION . .3-2 TUNING FAULTS . .3-3 KHF 950/990 CONTROLS-GENERAL . .3-3 KCU 1051 CONTROL DISPLAY UNIT OPERATION . -
Time Signal Stations 1By Michael A
122 Time Signal Stations 1By Michael A. Lombardi I occasionally talk to people who can’t believe that some radio stations exist solely to transmit accurate time. While they wouldn’t poke fun at the Weather Channel or even a radio station that plays nothing but Garth Brooks records (imagine that), people often make jokes about time signal stations. They’ll ask “Doesn’t the programming get a little boring?” or “How does the announcer stay awake?” There have even been parodies of time signal stations. A recent Internet spoof of WWV contained zingers like “we’ll be back with the time on WWV in just a minute, but first, here’s another minute”. An episode of the animated Power Puff Girls joined in the fun with a skit featuring a TV announcer named Sonny Dial who does promos for upcoming time announcements -- “Welcome to the Time Channel where we give you up-to- the-minute time, twenty-four hours a day. Up next, the current time!” Of course, after the laughter dies down, we all realize the importance of keeping accurate time. We live in the era of Internet FAQs [frequently asked questions], but the most frequently asked question in the real world is still “What time is it?” You might be surprised to learn that time signal stations have been answering this question for more than 100 years, making the transmission of time one of radio’s first applications, and still one of the most important. Today, you can buy inexpensive radio controlled clocks that never need to be set, and some of us wear them on our wrists. -
STANDARD FREQUENCIES and TIME SIGNALS (Question ITU-R 106/7) (1992-1994-1995) Rec
Rec. ITU-R TF.768-2 1 SYSTEMS FOR DISSEMINATION AND COMPARISON RECOMMENDATION ITU-R TF.768-2 STANDARD FREQUENCIES AND TIME SIGNALS (Question ITU-R 106/7) (1992-1994-1995) Rec. ITU-R TF.768-2 The ITU Radiocommunication Assembly, considering a) the continuing need in all parts of the world for readily available standard frequency and time reference signals that are internationally coordinated; b) the advantages offered by radio broadcasts of standard time and frequency signals in terms of wide coverage, ease and reliability of reception, achievable level of accuracy as received, and the wide availability of relatively inexpensive receiving equipment; c) that Article 33 of the Radio Regulations (RR) is considering the coordination of the establishment and operation of services of standard-frequency and time-signal dissemination on a worldwide basis; d) that a number of stations are now regularly emitting standard frequencies and time signals in the bands allocated by this Conference and that additional stations provide similar services using other frequency bands; e) that these services operate in accordance with Recommendation ITU-R TF.460 which establishes the internationally coordinated UTC time system; f) that other broadcasts exist which, although designed primarily for other functions such as navigation or communications, emit highly stabilized carrier frequencies and/or precise time signals that can be very useful in time and frequency applications, recommends 1 that, for applications requiring stable and accurate time and frequency reference signals that are traceable to the internationally coordinated UTC system, serious consideration be given to the use of one or more of the broadcast services listed and described in Annex 1; 2 that administrations responsible for the various broadcast services included in Annex 2 make every effort to update the information given whenever changes occur. -
Heart Rate Variability Analysis System
Heart Rate Variability Analysis System Clinical Information VERSION 3.O. SA - 3000P Clinical Manual Clinical 3000P CONTENTS 1. ABOUT SA-3000P------------------------------------------------------------------------------------4 VER.3.0. 2. HRV, ITS BACKGROUND INFORMATION 2.1. HRV, ITS DEFINITION----------------------------------------------------------------------------------6 2.2. GENERATION OF HRV--------------------------------------------------------------------------------7 2.3. HISTORY OF HRV---------------------------------------------------------------------------------------9 2.4. ABOUT THE TASK FORCE--------------------------------------------------------------------------10 2.5. STRESS AND AUTOMNOMIC NERVOUS SYSTEM------------------------------------------11 2.6. THE MEANING OF DEPRESSED HRV-----------------------------------------------------------12 3. METHODOLOGY AND TERMINOLOGY OF HRV ANALYSIS 3.1. METHODOGOLY----------------------------------------------------------------------------------------14 3.2. TERMINOLOGY-----------------------------------------------------------------------------------------16 3.2.1. Time Domain parameters---------------------------------------------------------------------------16 3.2.1.1 SDNN 2 3.2.1.2 SDNN Index 3.2.1.3. RMS-SD 3.2.2. Frequency Domain Parameters----------------------------------------------------------------17 3.2.2.1. Total Power (TP) 3.2.2.2. Very Low Frequency (VLF) 3.2.2.3. Low Frequency (LF) 3.2.2.4. High Frequency (HF) 3.2.2.5. LF/HF Ratio 3.2.2.6. Normalized Low Frequency -
Time and Frequency Users' Manual
,>'.)*• r>rJfl HKra mitt* >\ « i If I * I IT I . Ip I * .aference nbs Publi- cations / % ^m \ NBS TECHNICAL NOTE 695 U.S. DEPARTMENT OF COMMERCE/National Bureau of Standards Time and Frequency Users' Manual 100 .U5753 No. 695 1977 NATIONAL BUREAU OF STANDARDS 1 The National Bureau of Standards was established by an act of Congress March 3, 1901. The Bureau's overall goal is to strengthen and advance the Nation's science and technology and facilitate their effective application for public benefit To this end, the Bureau conducts research and provides: (1) a basis for the Nation's physical measurement system, (2) scientific and technological services for industry and government, a technical (3) basis for equity in trade, and (4) technical services to pro- mote public safety. The Bureau consists of the Institute for Basic Standards, the Institute for Materials Research the Institute for Applied Technology, the Institute for Computer Sciences and Technology, the Office for Information Programs, and the Office of Experimental Technology Incentives Program. THE INSTITUTE FOR BASIC STANDARDS provides the central basis within the United States of a complete and consist- ent system of physical measurement; coordinates that system with measurement systems of other nations; and furnishes essen- tial services leading to accurate and uniform physical measurements throughout the Nation's scientific community, industry, and commerce. The Institute consists of the Office of Measurement Services, and the following center and divisions: Applied Mathematics -
Radiorama N.58.Pdf
Panorama radiofonico internazionale n. 58 Dal 1982 dalla parte del Radioascolto Rivista telematica edita in proprio dall'AIR Associazione Italiana Radioascolto c.p. 1338 - 10100 Torino AD www.air-radio.it lll’angolo delle QSL storiche … radiorama PANORAMA RADIOFONICO INTERNAZIONALE organo ufficiale dell’A.I.R. Associazione Italiana Radioascolto recapito editoriale: radiorama - C. P. 1338 - 10100 TORINO AD e-mail: [email protected] AIR - radiorama - Responsabile Organo Ufficiale: Giancarlo VENTURI - Responsabile impaginazione radiorama: Bruno PECOLATTO - Responsabile Blog AIR-radiorama: i singoli Autori - Responsabile sito web: Emanuele PELICIOLI ------------------------------------------------- Il presente numero di radiorama e' pubblicato in rete in proprio dall'AIR Associazione Italiana Radioascolto, tramite il server Aruba con sede in località Palazzetto, 4 - 52011 Bibbiena Stazione (AR). Non costituisce testata giornalistica, non ha carattere periodico ed è aggiornato secondo la disponibilità e la reperibilità dei materiali. Pertanto, non può essere considerato in alcun modo un prodotto editoriale ai sensi della L. n. 62 del 7.03.2001. La responsabilità di quanto pubblicato è esclusivamente dei singoli Autori. L'AIR-Associazione Italiana Radioascolto, costituita con atto notarile nel 1982, ha attuale sede legale presso il Presidente p.t. avv. Giancarlo Venturi, viale M.F. Nobiliore, 43 - 00175 Roma SR1 EUROPAWELLE SAAR 1421kHz, GERMANIA (anni ‘80) RUBRICHE : Pirate News - Eventi Collabora con noi, invia i tuoi articoli come da protocollo. Il Mondo in Cuffia - Scala parlante e-mail: [email protected] Grazie e buona lettura !!!! Vita associativa - Attività Locale Segreteria, Casella Postale 1338 10100 Torino A.D. radiorama on web - numero 58 e-mail: [email protected] ------------------------ [email protected] Rassegna stampa – Giampiero Bernardini SOMMARIO e-mail: [email protected] ------------------------ In copertina : "Musica a richiesta - Radio Trst", opera di Vilma Coti (cortesia Rubrica FM – Giampiero Bernardini Dorigo Valdi). -
Nbs Technical Note 674 National Bureau of Standards
NBS TECHNICAL NOTE 674 NATIONAL BUREAU OF STANDARDS The National Bureau of Standards' was established by an act of Congress March 3, ,1901. The Bureau's overall goal is to strengthen and advance the Nation's science and technology and facilitate their effective application for public benefit. To this end, the Bureau conducts research and provides: (1) a basis for the Nation's physical measurement system, (2) scientific and technological services for industry and government, (3) a technical basis for equity in trade, and (4) technical services to promote public safety. The Bureau consists of the Institute for Basic Standards, the Institute for Materials Research, the Institute for Applied Technology, the Institute for Computer Sciences and Technology, and the Office for Information Programs. THE INSTITUTE FOR BASIC STANDARDS provides the central basis within the United States of a complete and consistent system of physical measurement; coordinates that system with measurement systems of other nations; and furnishes essential services leading to accurate and uniform physical measurements throughout the Nation's scientific community, industry, and commerce. The Institute consists of the Office of Measurement Services, the Office of Radiation Measurement and the following Center and divisions: Applied Mathematics - Electricity - Mechanics - Heat - Optical Physics - Center for Radiation Research: Nuclear Sciences; Applied Radiation - Laboratory Astrophysics * - Cryogenics ' - Electromagnetics - Time and Frequency *. THE INSTITUTE FOR MATERIALS RESEARCH conducts materials research leading to improved methods of measurement, standards, and data on the properties of well-characterized materials needed by industry, commerce, educational institutions, and Government; provides advisory and research services to other Government agencies; and develops, produces, and distributes standard reference materials.