Education‎ > ‎

WWV

posted Feb 12, 2017, 7:14 PM by Charles Boling   [ updated Feb 12, 2017, 7:25 PM ]
Not part of the Amateur Radio service, but of interest to amateurs and other users of the HF bands, as well as people looking to find the correct time, WWV is one of the most well-known shortwave stations.  Not everyone is familiar with it, however, and I thought a brief overview of the WWV family of stations might be useful.


Current Stations

WWV

Location: Fort Collins, CO

Voice: Male (after HI)

Frequencies / Power (ERP) / Directionality:
 2.5 MHz
2.5 kW
 Omni
 5 MHz
10 kW
 Omni
10 MHz
 10 kW
 Omni
 15 MHz
 10 kW
 Omni
 20 MHz
 2.5 kW
 Omni
 25 MHz
 2.5 kW
 Omni
Services:
  • Audio reference tones: 600Hz (odd minutes), 500Hz (even minutes), 440 Hz (hourly)
  • Time: 1-second tick, 1-minute voice time announcement, continuous BCD date/time codes on 100Hz PWM tone
  • Reports: hourly reports on satellite health and propagation conditions, storm warnings

WWVH

Location: Kekaha, Kauai, HI

Voice: Female (before CO)

Frequencies / Power (ERP) / Directionality:

 2.5 MHz
5 kW
 Omni
 5 MHz
10 kW
 Westward
10 MHz
 10 kW
 Westward
 15 MHz
 10 kW
 Westward
Services: Same as WWV, except no 440 Hz tone

WWVB

Location: Fort Collins, CO

Frequency (kHz): 60

Power (kW):

Directionality: Omnidirectional

Services:
  • Time: continuous BCD date/time codes w/ DST/Leap indicators using PSK/ASK

Historical Timelines

WWV

  • 1919 - WWV call letters assigned to NBS (forerunner to NIST)
  • 1920 - Broadcast Friday night concerts on 500m/600kHz (50W AM) from Washington DC
  • 1921 - Agriculture market news broadcast on 750kHz (2kW spark gap)
  • 1923 - Broadcast Radio Frequency standards from 125kHz - 2MHz
  • 1933 - Moved to Beltsville, MD; Higher precision 5, 10MHz (30kW)
  • 1935 - Added 10,15MHz (20kW)
  • 1937 - Added 440Hz musical pitch, 1-second pulses, ionosphere bulletins
  • 1945 - USNO-synchronization; time announcements (Morse code)
  • 1946 - 30 & 35 MHz added (dropped in 1953)
  • 1950 - Voice time announcements every 5 minutes
  • 1960 - Digital time codes enabled self-setting clocks
  • 1966 - Moved to Fort Collins, CO
  • 1967 - GMT instead of local time
  • 1971 - Current BCD digital time code; voice announcements every minute
  • 1972 - First leap second broadcast
  • 1974 - UTC instead of UTC
  • 1991 - Solid state memory used instead of drums for voice recordings; DST notification improved and year added

WWVH

  • 1948 - Began on 5, 10, 15 MHz (1kW) from Kihei, Maui, HI
  • 1956 - 2kW, more accurate
  • 1964 - Voice announcements
  • 1965 - 2.5MHz (1kW) added
  • 1971 - Moved to Kekaha, Kauai, HI, current power levels, female voice, new digital time code  (telegraphic code turned off)
  • 1991 - Solid state memory

WWVB

  • 1956 - KK2XEI broadcast experimental carrier on 60 kHz @ 40W (then reduced to 1.4W) from Boulder, CO
  • 1957 - LF proved to provide more stable time reference than WWV/WWVH
  • 1960 - WWVL began operation in Sunset, CO on 20 kHz
  • 1963 - WWVB broadcast from Ft. Collins, CO on 60 kHz @ 5kW, enjoying better propagation due to good soil conductivity and not being right next to mountains
  • 1965 - BCD time code enabled self-setting clocks
  • 1972 - WWVL (now 2kW) went away
  • 1999 - Power increased to 50 kW ERP; consumer WWVB-synchronized clocks became commonplace

What good is WWV* to amateurs?

Time Reference

Yes, you can also get the time of day from the Internet using NTP, or over the telephone, rather than via RF.  Isn't choice great?

A precise short-term time reference can also be handy for calibrating computer clock for synchronized protocols like Slow-Scan TV

Frequency Reference

Want to check / adjust the accuracy of your VFO?  Zero-beat to WWV; it's accurate to a few parts in 10^13 (Yes, that's better than one part in a trillion -- that's a millionth of a Hz for the 10MHz signal).  That's far more stability than you'll ever need for your puny transmitter!

Want to check your sound card? The audio tones from WWV are still the gold standard in terms of frequency stability.

Propagation Indicator

This is the #1 use for HF operators, whether amateur, commercial, or government/military.  Quick, how many HF beacons operating in the amateur bands do you know the details (frequency, location)?  They're out there, but can you name some?  Thought so.  How about WWV? After reading the material above, do you remember any of the frequencies or the locations?  It's hard to beat the utter memorizing convenience of "Colorado Man, Hawaii Girl" exactly every 5 MHz (plus 1/2 the bottom one).  Add to that a nice AM voice format (you don't need to know Morse code, or remember specific call signs or time slots) that's receivable by about anyone on anything, and you've got something useful.  By checking the signal strength from Colorado & Hawaii on various frequencies, you can make predictions for amateur bands above/below them, to places closer/farther than the time stations.  No, it won't tell you if 10m is open to Finland, but it can tell you a lot.

In spite of the ease of remembering the WWV frequencies, if your HF rig is new enough to support memories, you might find it handy put program them; that way you can quickly switch between them for comparison with a single keypress, instead of having to type the frequency out every time.

Reliable signal source

It's always on, from a known location and power, and strong enough that you're all but guaranteed to pick it up on at least one frequency, and usually several (which you can usually guess roughly based on the time of day), making it a handy way to test/demonstrate a receiver system.  Calling CQ and not getting a response? The nice man in Colorado will always talk to you.

Comments