Recent radios of that grade all have TCXOs, and that level of performance is really not that hard to achieve today at constant temperature.
My Yaesu FT-1000 Mk5 Field (with TCXO) drifts much less than 0.5 Hz at 14 MHz between 30 minutes and one hour after being turned on (in receive), but a couple of Hz during the 1st 1/2 hour (from memory, I did not record the data). I have not tried after continuous, prolonged transmission. I need to retake this data now that I have much better equipment. With regard to accuracy, the rig is about 0.82 Hz low at 14 MHz after warm-up (original factory adjustment, the rig is about 2.5 years old), measured in AM transmit mode, using a 40dB power attenuator on the output driving an HP 5370A counter with 1 sec gate time, with a Thunderbolt GPSDO as external reference. My older Kenwood TS-440S/AT radio (no TCXO, bought new in 1991), drifts about 100 Hz (at 14 MHz) during the 1st 30 minutes of operation (receive) but is quite stable after that ( I did not measure how much, but absolutely no noticeable drift in normal operation, for instance using WWV's zero beat as a reference), regardless of Tx or Rx operation. Didier KO4BB Colin Bradley wrote: > 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 > time-nuts@febo.com > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > > _______________________________________________ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
