Information by Phone

The Geophysical Alert Broadcast is also available as a telephone recording. This is useful if you cannot hear WWV or WWHV on the air due to poor propagation. The message can be reached by calling (if necessary) the international exchange, then 1 for the United States, followed by (303) 497 3235. This message lasts about 40 seconds, and is updated every 3 hours. If you're trying some long distance listening, and neither WWV nor WWVH are audible in your area, the short call to Boulder may save a lot of time. At off-peak rates it can be very economical, even long-distance.

In Australia, a similar service is offered by the Ionospheric Prediction Service near Sydney. Their propagation message is available free of charge by dialing 61 for Australia, and then 2 269 8614.

Information on the Web

Chances are you have access to the Web. In that case, current solar activity is available on-line. Check our Hitlist for details since this is kept up to date.

APPENDIX

a index. A 3-hourly 'equivalent amplitude' of geomagnetic activity for a specific station or network of stations expressing the range of disturbance of the geomagnetic field. The a index is scaled from the 3-hourly K index according to the following table:

K 0 1 2  3 4 5 6 7 8 9 a 0 3 7 15 27 48 80 140 240 400

x-ray flare class. Ranking of a flare based on its x-ray output. Flares are classified according to the order of magnitude of the peak burst intensity (I) measured at the earth in the 0.1 to 0.8 nm wavelength band as follows:

Peak, 0.1 to 0.8 nm band Class (Watt/square metre) B I < 10-6 C 10-6 I < 10-5 M 10-5 I < 10-4 X I 10-4

A multiplier is used to indicate the level within each class. For example:

M6 = 6 X 10^-5 Watt/square metre

Additional Information Sources

Space Environment Laboratory Computer Bulletin Board

If you have a modem-equipped computer, you can use it to call the Space Environment Laboratory's free computer bulletin board and obtain additional solar and radio propagation-related data. This board operates 24 hours a day, 7 days a week and is located in Boulder, Colorado in the United States. Access is free except for the charges made by your phone company for the call.

The telephone number is 1 for North America, then (303) 497-5000. The communications parameters are as follows: 300, 1200 or 2400 baud; data word protocol is 8-bit/character with 1 stop bit and no parity. The board is completely menu-driven and contains an extensive Help section.

Available material includes HF Propagation Reports based on actual operational experience during the previous several hours, regular Solar Reports which give more extensive data on solar and geomagnetic activity than in the Geophysical Alert Broadcasts, and Maximum Usable Frequency (MUF) predictions based on user-supplied geographic coordinates and existing sunspot numbers. Data on the board is continuously updated from the Space Environment Laboratory's worldwide data base.

NOTE: This computer bulletin board uses the Bell Standard tones for its data communications. Many modems outside the U. S. use other standards (e.g CCITT) so consult your equipment operating instructions before attempting to contact this bulletin board from outside the U. S.

What Next?

If you have any further specific questions about propagation, here are some further sources of information:

Space Environment Services Center
NOAA/ERL R/E/SE2
325 Broadway
Boulder, Colorado 80303
U S A

IPS Radio and Space Services,
P.O. Box 702,
Darlinghurst NSW 2010
Australia

Further Reading:

'Proceedings 1991'. Editors: John Bryant, Fritz Mellberg et al. Publisher: Fine Tuning Special Publications, RRT #5, Stillwater OK 74074 USA. Price: US$19.50 cover price plus US$2.00 postage in USA, US$3.00 elsewhere surface mail, US$15.00 airmail.

A board of twelve editors has selected a range of in-depth articles about tropical band propagation, antennas (e.g. the T2FD & the famous Beverage. This project is non-profit making.

Did you find this guide useful? What could be improved? Send your comments to:

David A. Rosenthal
P. O. Box 1502
Ridgecrest, CA 93556
U S A