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Mark Your Calendar for the November 2008 Frequency Measuring Test

11/10/2008

On Wednesday, November 12 at 9:45 PM EST (Thursday, November 13 at 0245 UTC), W1AW will once again host the ARRL Fall Frequency Measuring Test (FMT), replacing the W1AW phone bulletin scheduled at that time. "These tests will exercise the capabilities of hams to measure important operating parameters, improve their understanding of complex radios and give them a better mental picture of their transmitted signals," Contributing Editor H. Ward Silver, N0AX, said in an October 2002 QST article describing the art and science of frequency measurement. "The goal is a more technically aware amateur confident of compliance with FCC regulations."

Today's amateurs tend to take for granted the accuracy of their transceiver's frequency readout. But, as Silver notes in his article, relying simply on a transceiver's digital readouts could mean part of your signal is outside the band edge -- in violation of FCC Part 97 rules. Transceiver or receiver readout accuracy "depends entirely on the quality of the receiver's master oscillator," he pointed out in QST.

In 2008, Silver said that activity on the digital modes has "skyrocketed with the advent of inexpensive radio interfaces and easy-to-use software. RTTY (radioteletype) remains the most popular data mode using simple FSK modulation. Critical to good performance on RTTY is using the proper 'shift,' or difference between the mark and space tones, encoding the 1s and 0s that make up the Baudot code." As such, the November FMT will take a step toward the measurement of shifts of FSK signals.

W1AW Station Manager Joe Carcia, NJ1Q, recommends that those planning to participate listen to W1AW's transmissions prior to the event to determine which band -- or bands -- will be best for measurement purposes.

The FMT will start with a general QST call from W1AW at exactly 9:45 PM EST on Wednesday (0245 UTC on Thursday), transmitted simultaneously on 3.5975 and 7.095 MHz. All identification and instructions will be transmitted in CW. The test will begin with an identification of the band on which the tones are to be transmitted (NOW 80 METERS). The tones to be used will be between 500 Hz and 2 kHz. The two tones will be transmitted in an alternating sequence of 10 seconds of each tone. Each tone will be transmitted three times for a total of 1 minute of continuous transmission on each band.

W1AW will then ID and identify the next band (QST DE W1AW 40 METERS) and the tone sequence will be repeated on the next band. The test will last for a period of approximately 15 minutes total and will end with a series of Vs followed by station identification. W1AW will identify before, during and after the transmissions.

West Coast participants have their own signal to check again this year, courtesy of Mike Fahmie, WA6ZTY.

Your report should be submitted via the FMT Report form on the W1AW FMT Web site. Along with your call sign and e-mail address, enter your most accurate measurement on each band and indicate whether you measured the W1AW or WA6ZTY signal (or both). There will be a window to list your equipment, describe the method you used to make the measurements and enter any Soapbox comments. W1AW will post the transmitted frequencies following the test on the FMT Web site, allowing participants to quickly determine the accuracy of their equipment and methods.

For more information, please check out "Frequency Measuring Test 2008," by H. Ward Silver, N0AX, in the November 2008 issue of QST. The article is also available on the ARRL Web site. Additional information about the FMT -- including a list of reference articles and updates to test schedules -- is on the W1AW Frequency Measuring Test Web page.



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