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 Previous: ARRL Announces Amateur Radio Today CD-ROM Presentation |  Next: President Haynie on hand for Tropical Hamboree |
By Stan Horzepa, WA1LOU
Contributing Editor
January 24, 2003
This week, Surfin' gives you something else to do during the Super Bowl halftime show.
In case you missed the announcement, the Super Bowl is on the tube this Sunday. Now that you know, you can make plans to watch the game, but what to do during the halftime show? I guess you can watch it, but I prefer to do something else as I typically find the show over-hyped and unlistenable to my Beatles-generation ears. So, let me suggest an alternative: calculate the safety of the RF emanating from your antenna system. Find out if it is safe for your Monday morning quarterback to toss the pigskin around the base of your tower while you are on the air.
 Is it safe? The Amateur Radio RF Safety Calculator will determine if the ether is harmless around your shack. |
The University of Texas Amateur Radio Club at Austin has a fine Web site that includes an on-line Amateur Radio RF Safety Calculator. The calculator is "a main beam power density estimation program intended for use as part of a routine evaluation of RF safety compliance with FCC regulations," according to the explanatory text at the top of the page, which is available in both English and French. FCC regulations require Amateur Radio operators to do a "routine evaluation" of the strength of the RF fields around their stations, subject to certain exemptions.
To use the calculator you need the average power in Watts at the antenna--rather than Peak Envelope Power or PEP--the antenna's gain (in dB), the distance (in feet) from the center of the antenna to the area of interest--ie, your Monday morning quarterback's 50-yard line--and the frequency (in MHz) of operation. Input the numbers, then click on the "Calculate RF Power Density" button, and read the results, which include estimated RF power density, maximum permissible exposure, distance to compliance from the center of the antenna, and most importantly, "Does the area of interest appear to be in compliance?" If the answer is "Yes," then you can return to the tube to enjoy the rest of the game, as Shania should be just about finished by then.
Until next time, keep on surfin'.
Editor's note:
Stan Horzepa, WA1LOU, resides in downtown Wolcott, Connecticut, and is a member
of the QQCC (QST quarter century club), i.e., he has been a QST writer for 25
years. Since getting his ticket in 1969, Stan has sampled nearly every entrée
in the Amateur Radio menu (including a stint as Connecticut Section Manager),
but he keeps coming back to his favorite preoccupations: VHF and packet radio.
As a result, he runs a 2-meter APRS digipeater and weather station (WA1LOU-15)
from his mountaintop location in central Connecticut. Stan has been a long time
advocate of using computers with Amateur Radio and wrote programs to dupe
contests and calculate antenna bearings way back in 1978. Today, he is on the
board of directors of the Tucson Amateur Packet Radio (TAPR) and uses his Mac
to surf the Internet searching for that perfect ham radio web page. To contact
Stan, send e-mail to wa1lou@arrl.net.
| Previous: ARRL Announces Amateur Radio Today CD-ROM Presentation | Next: President Haynie on hand for Tropical Hamboree |
