The tone's the thing for 2004 ARRL
Frequency Measuring Test
There's a new twist to the ARRL Maxim Memorial Station W1AW Frequency
Measuring Test (FMT).
The 2004 FMT takes place November 18 starting at 0245 UTC (the evening
of Wednesday, November 17, in US time zones), replacing the W1AW phone
bulletin normally transmitted then.
Rather than measuring the transmission's carrier frequency, participants
in this year's FMT will attempt to accurately determine the frequency
of an audio tone. Engineer and ARRL Contributing Editor Ward Silver, N0AX,
says measuring an audio tone will reinforce understanding of the relationship
between carrier frequency and the components of a transmitted signal.
"The carrier is suppressed for SSB signals, leaving only the sideband
components," Silver explains in "The FMT Strikes a New Tone,"
in November QST. "The frequency of components of the modulating audio
signal is preserved as the difference between the carrier frequency and
the transmitted component. A single modulating tone results in a single
transmitted component."
W1AW will make the 2004 FMT transmissions on 80, 40 and 20 meters. The
FMT will begin with a general W1AW "QST" starting at 0245 UTC
sent simultaneously on the three W1AW transmission frequencies. The test
itself will consist of three 60-second tone transmissions on each band,
followed by a station identification. The whole test will run for about
15 minutes and will end with a station ID.
The tone frequency will be the same on all three bands.
During the 2004 FMT, W1AW will indicate the band on which participants
should measure. After the initial call-up, W1AW will begin the test by
announcing, "Now 80 meters." Except for the tone transmission,
all transmissions will be voice.
Frequencies are 3990 kHz (LSB), 7290 kHz (LSB) and 14,290 kHz (USB).
All frequencies will be accurate to at least
0.1 ppm (eg, 3990 ±0.4 Hz).
Submitted reports should include name, call sign, location, time of reception
and, of course, the tone frequency. Those using an indirect measurement
method also should include calculations showing how they arrived at the
tone frequency.
For additional details on indirect and direct measurement methods, see
Silver's article "The
ARRL Frequency
Measuring Tests," on the ARRL Web site, or in Oct 2002 QST.
Send entries postmarked by Friday, December 17, 2004, to W1AW/FMT, ARRL,
225 Main St, Newington, CT 06111.
Separate reports for each band are welcome.
All entrants qualify for a Certificate of Participation.
Those coming closest to the measured frequency will be listed in the test
report and get special recognition on their certificates.
Source: ARRL Letter - courtesy of The
American Radio Relay League
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