The MVUS FMT:
December 2009 2M Transmission Information
Last Minute News!
Nominal 2M frequency (+/- 50Hz) for the December, 2009 FMT: 144.2743 MHz
The Midwest VHF/UHF Society (located in Southwest Ohio) Frequency Measuring Test will be held on December 28-30, 2009. In addition to signals on 80, 40, and 20 meters, we will also transmit on 2M with the idea of providing both an opportunity for those interested to measure a VHF frequency to high precision, and to provide a calibration signal for the general VHF community.
The test will begin with a call-up starting at about 1445 UTC (0945 EST) on Monday, 28 December. The continuous transmission period will begin at 1500 UTC (1000 EST) and will end at 1500 UTC (1000 EST) on Wednesday, December 30.
The signal will be a continuous carrier with CW ID every ten minutes. We will use MVUS club call W8KSE and the transmitter will be at Mike, W8RKO's QTH in Centerville, Ohio (grid square EM79wq).
The 144 MHz transmission has two purposes:
First... If you want to try to precisely measure its frequency, have at it! The signal is generated by a low-noise frequency synthesizer driven by a Cesium Beam atomic frequency standard that is monitored against the GPS system, which in turn is compared by the US Naval Observatory and the National Institute of Standards and Technology (NIST, formerly the NBS). After the test, we will announce the 2M frequency to an accuracy of better than one thousandth of one Hertz, and you can see how you did.
Second... Even if you don't go that far, the "nominal" frequency shown at the top of this page is accurate enough to check the calibration of almost any commercial 2M SSB rig. Even with an optional Temperature Controlled Crystal Oscillator ("TCXO"), the Icom, Kenwood, and Yaesu rigs we've looked at have a specified frequency accuracy of at best 0.5 part per million ("PPM"). With the standard oscillator, the stability is typically 2 or 3 PPM.
0.5 PPM translates to plus or minus 0.5 Hertz at 1 MHz, or at 144 MHz, 72 Hertz. Three PPM is about 420 Hertz at 2M. The frequency noted at the top of this page is within 50 Hertz of the true value. That's close enough to calibrate your dial as accurately as is worthwhile given a 0.5 PPM oscillator.
Since the signal will be very stable over the 48 hours of the transmission, you can use it measure how your rig drifts as it warms up. An easy way to do that is to hook its audio output (in SSB mode) to your PC sound card and use software like Spectrum Lab to view the output tone; any change in the tone represents a change in the radio's frequency.
If you'd like to submit your measurement of the 2M frequency, do so by January 15, 2010 using the new, improved submission form at www.febo.com/pages/mvus-fmt/entry_form.html.
We hope this FMT will encourage new experiments taking advantage of the long transmission duration. Therefore, a prize will be awarded to the most interesting report received, as determined by the MVUS Official Committee on Such Things.
If you have any questions, please send them to fmt@mvus.org. We will publish the official frequencies shortly after the submission deadline to time-nuts and fmt-nuts, and will make the full results available on the MVUS FMT web page as soon as we can.
For discussion about off-air frequency measurement, we suggest you check out the FMT-nuts mailing list, sponsored by Connie Marshall, K5CM. For details, go to http://tech.groups.yahoo.com/group/FMT-nuts.