For those interested in HF radio frequency and propagation measurement,
here is an announcement about a test transmission my local group in
Dayton, Ohio is going to run over the holidays.
More details below, but in short we're going to put out a low power
(about 5 watts) signal on three HF ham bands simultaneously, for 48
hours continuously (an unmodulated signal except for a morse code ID
every ten minutes).
If all goes according to plan, the RF chain will be an FTS-4100 Cesium
standard driving three low noise PTS synthesizers (two of them the very
low phase noise SX51 models). The FTS-4100 will be monitored in real
time against GPSDO so we'll have a pretty good idea of its offset and
stability throughout the test.
What's cool about this is that the 48 hour transmission period will
allow observations of propagation effects such as Doppler shift as the
ionosphere raises and lowers.
John
----
The Midwest VHF/UHF Society (MVUS, located in Southwest Ohio) is pleased
to announce that the third MVUS Frequency Measuring Test will be held on
December 28-30, 2009.
The MVUS Frequency Measuring Test is intended to supplement, not
replace, the ARRL FMT.
The test will use a novel format. Instead of the usual 5 to 15 minute
test, we will transmit simultaneously and continuously on 80, 40, and 20
meters for 48 hours. We hope this long transmission period, which will
encompass two full propagation days, will encourage new techniques and
experiments. For example, it should be possible to measure Doppler shift
caused by ionospheric raising and lowering.
The test will begin with a call-up starting at about 1445 UTC (0945 EST)
on 28 December. The continuous transmission period will begin at 1500
UTC (1000 EST) on Monday, December 28) 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.
Transmissions will be from W8KSE in Dayton, Ohio (grid square EM79).
Here are more details:
Start time 1500 UTC (1000 EST) Monday, December 28, 2009.
Nominal frequencies: 3577, 7055, and 14055 kHz, plus or minus QRM.
NOTE: Check here right before the test for last minute frequency changes.
Power: about 5 watts.
Antenna: Vertical on 80M, inverted vee on 40M, and 3 element yagi at
about 90 feet, aimed west, on 20 meters,
Submit entries 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 (and experimenters!)
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. We also are planning
other performance based prizes, but have not finalized those or the
prize categories at this time.
We will publish the official frequencies to time-nuts and fmt-nuts
shortly after the submission deadline , and will make the full results
available on the MVUS FMT web page as soon as we can.
Our goal is to transmit a signal known in frequency to parts in 10e-12
(i.e., less than 0.0001 Hz error at 10 MHz) and stable to a similar
level during the course of the transmission, as they will be derived
from an on-site Cesium-based reference. Frequencies will be measured at
the transmitter site with a system capable of microHertz resolution
referenced to a GPS disciplined oscillator, and will also be monitored
by another station in groundwave range that can measure the frequencies
with similar accuracy.
Further information will be posted at
http://www.febo.com/time-freq/mvus-fmt.
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.
If you have any questions, please send them to [email protected].
Looking forward to a fun event!
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