WWV (radio station)
WWV is a shortwave ("high frequency" or HF) radio station, located near Fort Collins, Colorado.
It has broadcast a continuous time signal since 1945, and implements United States government frequency standards, with transmitters operating on 2.5, 5, 10, 15, 20, and 25 MHz.
[2] WWV was established in 1919 by the Bureau of Standards in Washington, D.C., making it one of the oldest continuously-operating radio stations in the United States.
WWV shares this site with longwave (also known as "low frequency" or LF) station WWVB, which transmits carrier and time code (no voice) at 60 kHz.
It is of particular importance in broadcasting, whether it be commercial, public, or private interests such as amateur radio operators, who use the station's transmissions to test their equipment.
[9] Each transmitter has a dedicated antenna, with a height corresponding to one-half of its wavelength, and an omnidirectional signal radiation pattern.
[15][16][17] As of May 1920 the Bureau's Radio Laboratory was reported to be conducting weekly Friday evening concerts from 8:30 to 11:00, transmitting on 600 kHz.
[12] A newspaper article the following August reported that the weekly concerts could be heard up to 100 miles (160 km) from Washington.
It also noted that "The bureau has been experimenting with the wireless music for several months, and has reached such an advanced stage of development that further investigation to them is useless, and they are going to discontinue the concerts.
"[19] However, the station continued to make occasional broadcasts, and in January 1921 a new distance record was announced when a listener in Chattanooga, Tennessee reported hearing the "jazzy waves whirling out from the Bureau of Standards".
[20] On December 15, 1920, WWV began broadcasting 500-word "Daily Radio Marketgrams", prepared by the U.S. Bureau of Markets, in Morse code on 750 kHz, which reportedly could be heard up to 200 miles (320 km) from Washington.
[21] However, on April 15, 1921 responsibility for the reports was transferred to four stations operated by the Post Office Department, including its WWX in Washington, D.C.[22] At the end of 1922, WWV's purpose shifted to broadcasting standard frequency signals.
These were an important aid to broadcasting and amateur stations, because their equipment limitations at the time meant they had difficulty staying on their assigned frequencies.
[23] Regularly scheduled operations began on March 6, 1923, consisting of seven transmitting frequencies ranging from 550 to 1,500 kHz (wavelengths of 545 to 200 meters).
Its signal could only cover the eastern half of the United States, and other stations located in Minneapolis and at Stanford University and the Massachusetts Institute of Technology were slowly making WWV redundant.
The station's impending shutdown was announced in 1926, but it was saved by a flood of protests from citizens who relied on the service.
The frequency and transmitting equipment was recovered, and the station was back on the air (with reduced power) on November 11.
[23] Beginning in 1913 the primary official time station broadcasting in the eastern United States was the Navy's NAA in Arlington, Virginia.
In June 1944, the United States Naval Observatory allowed WWV to use the USNO clock as a source for its time signals.
This "NASA time code" was modulated onto a 1 kHz audio tone at 100 Hz, sounding somewhat like a monotonous repeated "baaga-bong".
[26] WWV moved to a location near Fort Collins on December 1, 1966,[27] enabling better reception of its signal throughout the continental United States.
[29][30] WWV, along with WWVB and WWVH, was recommended for defunding and elimination in NIST's Fiscal Year 2019 budget request.
[32] WWV's 20 MHz signal was used for a unique purpose in 1958: to track the disintegration of Russian satellite Sputnik 1 after the craft's onboard electronics failed.
John D. Kraus, a professor at Ohio State University, knew that a meteor entering the upper atmosphere leaves in its wake a small amount of ionized air.
In particular, he observed that satellites do not fall as one unit; instead, the spacecraft broke up into its component parts as it moved closer to Earth.
WWVH makes an identical time announcement, starting 15 seconds before the minute tone, in a female voice.
After the 1967 switch to GMT, the announcement changed to "National Bureau of Standards, WWV, Fort Collins, Colorado; next tone begins at X hours, Y minute(s), Greenwich Mean Time.
[9] WWV transmits 44-second official announcements from various government departments (in lieu of the standard frequency tones) on an hourly schedule:[37] Solar-terrestrial indices for 23 May follow.
Inquiries regarding these transmissions may be directed to the National Institute of Standards and Technology, Radio Station WWV, 2000 East County Road 58, Fort Collins, Colorado, 80524.WWV accepts reception reports sent to the address mentioned in the station ID, and responds with QSL cards.
Also like the IRIG timecode, numeric data (minute, hour, day of year, and last two digits of year) are sent in binary-coded decimal (BCD) format rather than as simple binary integers: Each decimal digit is sent as two, three, or four bits (depending on its possible range of values).
