That's interesting -- from your earlier message, I thought they were still running the Harris exciters for the test itself. It'll be interesting to monitor the drift during the test.
My plan is to record audio (W1AW plus my known-frequency marker) of all three bands simultaneously for the whole test period, so if the propagation gods are smiling upon us, I'll be able to look at the beginning-to-end drift. Two of the bands will use HP 3586C selective voltmeters driven from an HP 5065A (using the internal tracking generator as the marker), while 40M will be on an Icom 746 with a PTS synthesizer hooked to the same 5065A providing the marker. The audio from all three receivers is fed into a 4-input Delta44 sound card and recorded as separate .wav files. It's a shame the test wasn't a week or two later -- I just acquired two more 3586Cs on eBay today so I would have been able to use the same hardware for all three bands. That'll have to wait until next year... (I really love the 3586C as an HF measurement machine.) I also hope that by next year I'll have the crystal in the Delta44 slaved to the external reference, and that will remove my last significant source of measurement uncertainty -- though the Delta44 sample rate seems to be very stable even on its own. John ---- Colin Bradley said the following on 11/15/2006 04:37 PM: > I received the following email from the station manager of W1AW. > > Hi Colin, > > I didn't want to answer your question too soon. > > On the days prior to the FMT, I conduct measurements at 1 hour, 3 and 6 hours > after initial warm-up. (And of course, this time frame includes the normal > broadcast schedule.) > > From what I can see, the drift on the Orion and Pro IIs is minimal. For > example, from the 3 to 6 hour time period (today), the "40-meter" Orion > drifted 0.12 Hz. The "80-meter" Pro II drifted about 0.11 Hz and the > "160-meter" Pro II drifted about 0.04 Hz. (You have to understand that these > three radios are here for evaluation only, and went through their respective > Service Departments before we received them.) > > And just now, I conducted a quick test to see what the "real short-term" > drift would be (given the time frame of the FMT). I didn't notice any > significant difference. > > I'm a little surprised at these numbers. But I have to go on what my counter > is telling me. Oddly enough, when we used to run the Harris exciters (during > past FMTs), it was not uncommon for me to see at least a 2-4 Hz difference in > the 3 to 6 hour time period. > > So we'll see... > > Good luck! > > 73, > > Joseph Carcia, NJ1Q > W1AW Station Manager > > Interesting...I would not have thought these transceivers were that stable. > Colin > > _______________________________________________ > time-nuts mailing list > [email protected] > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > > _______________________________________________ time-nuts mailing list [email protected] https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
