Time and Frequency Services

Time and Frequency services are presently available from stations WWV and WWVB in Fort Collins, Colorado, and from WWVH in Kauai, Hawaii.

WWVH Broadcast Format

Format messages available via telephone: (808) 335-4363

Location of WWVH is at:

Latitude:   21 degrees, 59 minutes, 26 seconds North
Longitude: 159 degrees, 46 minutes, 00 seconds West

Address of WWVH is:

NBS Radio Station WWVH
PO Box 417
Kekaha, Kauai, HI 96752

Standard Broadcast Frequencies and Radiated Power:

 2.5  MHz:   5,000 Watts
 5.0  MHz:  10,000 Watts
10.0  MHz:  10,000 Watts
15.0  Mhz:  10,000 Watts


Hourly Schedule

Minutes after the top of the hour/Broadcast information:

01 min    400 Hz 1-HOUR mark
03 min    reserved
29 min    Station Identification
47 min    Omega reports
48 min    Storm information
49 min    Storm information
50 min    Storm information
59 min    Station Identification

In addition, minutes 08-10 and minutes 15-19 have no audio tones so that informational broadcasts out of WWV can be heard.

The broadcasts on 5, 10, and 15 MHz from WWVH are from phased vertical half-wave dipole arrays. They are designed and oriented to radiate a cardioid pattern directing maximum gain in a westerly direction. The 2.5 MHz antenna at WWVH is a half-wave dipole.

At both WWV and WWVH, double sideband amplitude modulation is employed with 50 percent modulation on the steady tones, 25 percent for the BCD time code, 100 percent for the seconds pulses, and 75 percent for voice.


Geophysical Alerts

Current geophysical alerts are broadcast in voice from WWV at 18 minutes after each hour, 46 minutes after at WWVH. The messages are changed approximate every six hours at 1800, 0000, 0600, and 1300 UTC.

Part A of the message gives the solar-terrestrial indices for the day; namely, the 1700Z solar flux from Ottawa, Canada at 2800 MHz, the estimated A value for Fredericksburg, Virginia, and the current, Boulder, Colorado, K-index. Part B gives the solar-terrestrial conditions for the previous 24 hours, and Part C gives the forecast for the next 24 hours. If stratwarm conditions exist, a brief advice is given at the end of the message.

1. Solar activity is classified as:

VERY LOW       Usually only quiet regions on the solar disk and no
               more than five of these; fewer than ten class-C
               subflares without centimetric radio burst of SID
               observed or expected.

LOW            Usually more than five but less than ten quiet
               regions on the solar disk; only class-C subflares
               without centimetric radio bursts or SID (sudden
               ionospheric disturbances) observed or expected.

MODERATE       Eruptive regions on the solar disk; fewer than five
               class-M X-ray events with centimetric radio bursts
               and SID observed or expected.

HIGH           Active regions on the solar disk; several class-M
               X-ray events with centimetric radio bursts and
               strong SID; and/or one to two importance=2
               chromospheric flares or class-X X-ray events
               observed or expected.

VERY HIGH      Region capable of producing protons on the sun; one
               or more chromospheric flares of importance-2 or
               greater; with outstanding centimetric radio bursts
               (500 flux units or greater), Class-X X-ray bursts,
               and major SID observed or expected.

2.  The geomagnetic field is classified as:
QUIET: A less than or equal to 7; no K-indices greater than 2
UNSETTLED: A less than 15; usually no k-indicies greater than 3
ACTIVE: A greater than or equal to 15 and less than 30; a few k-indices of 4.

   The geomagnetic storms are classified as:
MINOR: A greater than 30 and less than 50; K-indicies mostly 4 and 5.
MAJOR: A greater than 50; some K-indices 6 or greater.
Sudden commencements indicated by beginning time to nearest minute.
Gradual commencement indicated by beginning time to nearest hour.

4.  The rest of the report as follows:


CLASS C        any solar X-ray burst with a peak flux at 1-8
               angstroms of less than 1 microwatt per square meter

CLASS M        a solar X-ray burst with a peak flux at 1-8
               angstroms, greater than or equal to 10 but less
               than 100 microwatts per square meter.

CLASS X        a solar X-ray burst with a peak flux at 1-8
               angstroms, greater than or equal to 100 microwatts
               per square meter.

               a flare of optical importance (at least 2B -
               BRIGHT) with a centimetric outburst of 500 flux
               units or more; or an X-ray event of Class-X
               intensity of duration 3 hours or more regardless of
               optical flare importance.

PROTON FLARE   protons by satellite detectors (or polar cap
               absorption by riometer) have been observed in time
               associated with Ha flare.

PROTON EVENT   a proton enhancement detected by Earth orbiting
               satellites with measured particle flux of at least
               10 protons per square centimeter per second per
               steradian of at least 10 Million electronvolts.

ABSORPTION     proton-induced absorption at least 2 dB as measured
               by a 30 MHz riometer located within the polar cap.

STRATWARM      reports of stratospheric warmings in the high
               latitude regions of winter hemisphere of the earth
               associated with gross distortions of the normal
               circulation associated with the winter season

Inquiries regarding these messages should be address to NOAA, Space Environment Services Center R43, Boulder, CO 80303. These messages are also available by dialing (303) 499-8129


The station identification and time-of-day announcement are pre- recorded -- not "live". The announcer for WWV is Don Elliott of Atlanta, Georgia. Mrs. Jane Barbe is the announcer for WWVH, and she is also from Atlanta.

TOURS: Guided tours are available at all NBS radio stations. However, arrangements for visiting the sites should be made in advance with the EIC. There aren't any 'regular' visiting hours.

Correspondence pertaining directly to station operations may be addressed to:

NBS Radio Station WWVH
PO Box 417
Kekaha, Kauai, HI 96752
(808) 335-4361

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