Your RF Cafe
April 1958 Radio-Electronics[Table of Contents]
These articles are scanned and OCRed from old editions of the Radio & Television News magazine. Here is a list of the Radio-Electronics articles I have already posted. All copyrights are hereby acknowledged.
WWV is the oldest continuously-operating radio station in the U.S. since first going on the air from Washington, D.C. in May 1920. It moved around an area near D.C. for a few years before being relocated to its current location in Boulder, Colorado, in 1966. WWVB, another time standard transmitter, had already been established in Boulder a few years earlier. Sister station WWVH is located in Hawaii.
The National Bureau of Standards (NBS) was renamed National Institute of Standards and Technology (NIST) in 1988, nearly a century after its inception in 1890. Having grown up not too far from Beltsville, Maryland, I remember driving by their main campus when the NBS sign was still on the lawn. The decision to change the name never did make sense, but then most of what government bureaucrats do perplex me. Rank and file employees, the ones who do the amazing work that comes from NIST, NASA, NIH, NSA, NSF, NOAA, et al, are pawns in the process.
1The Department of Commerce's Boulder Labs were dedicated on September 14, 1954. The Boulder Labs have evolved from the National Bureau of Standards' Central Radio Propagation Laboratory to today's National Institute of Standards and Technology, National Oceanic and Atmospheric Administration, and National Telecommunications and Information Administration's Institute for Telecommunication Sciences.
NIST radio station WWV broadcasts time and frequency information 24 hours per day, 7 days per week to millions of listeners worldwide. WWV is located in Fort Collins, Colorado, about 100 kilometers north of Denver. The broadcast information includes time announcements, standard time intervals, standard frequencies, UT1 time corrections, a BCD time code, geophysical alerts and marine storm warnings. Broadcast Frequencies WWV operates in the high frequency (HF) portion of the radio spectrum. The station radiates 10,000 W on 5, 10, and 15 MHz; and 2500 W on 2.5 and 20 MHz. Each frequency is broadcast from a separate transmitter. Although each frequency carries the same information, multiple frequencies are used because the quality of HF reception depends on many factors such as location, time of year, time of day, the frequency being used, and atmospheric and ionospheric propagation conditions. The variety of frequencies makes it likely that at least one frequency will be usable at all times.
WWV Calls Attention to the fact that, besides providing correct time, it offers a number .of less well known services. For example, a standard musical pitch, 440 cycles, is broadcast by the National Bureau of Standards over its shortwave stations WWV (Beltsville, Md.) and WWVH (Maui, Hawaii). These broadcasts make a standard pitch available day and night throughout the United States and much of the world. A 600-cycle note is also broadcast. This together with the 440-cycle tone is used by scientists, electronic engineers and manufacturers in the measurement of short intervals of time and for calibrating instruments and devices that operate in the audio and ultrasonic frequency ranges. Both the 440- and 600-cycle tones are obtained from an electronic, crystal-controlled oscillator and are accurate as transmitted to better than 1 part in 100 million.
The two frequencies are broadcast alternately, starting with 600 cycles on the hour for 3 minutes, interrupted 2 minutes, followed by 440 cycles for 3 minutes and interrupted for 2 minutes. Each 10-minute period is the same except that WWV is off the air for 4 minutes beginning at 45 minutes after each hour, and WWVH is silent, in addition, for a 34-minute period each day beginning at 1900 Universal time or 1400 Eastern standard time. WWV broadcasts simultaneously on 2.5, 5, 10, 15, 20 and 25 mc. WWVH broadcasts on 5, 10 and 15 mc.
During the announcement intervals (19 1/2 and 49 1/2 minutes after the hour from WWV and 9 and 39 minutes after the hour from WWVH) these stations transmit propagation notices applying to transmission paths over the North Atlantic and North Pacific, respectively. The notices, in International Morse code, consist of the letter W, U or N followed by digits 1 to 9. W indicates ionospheric disturbance in progress or expected; U means unstable conditions with communication possible with high power and N means no warning.
The numbers indicate the propagation conditions expected during the next 12 hours. They have the following meanings: 1 - Impossible, 2 - Very Poor, 3 - Poor, 4 - Fair to Poor, 5 - Fair, 6 - Fair to Good, 7 - Good, 8 - Very Good, 9 - Excellent.
Posted June 3, 2014