At 07:20 AM 1/7/2007, Brian Kassel wrote: >Hi Jim: > > As always, thanks very much for taking the time to reply and your >help in getting this problem fixed. Yes, feeding the PTC directly off >of the main power supply must lead to some heat variance due to the >inevitable voltage sag caused when going from TX to RX. However, I just >have to ask a question here. How come no one else is seeing this 22 >Hz., 10 second drift when switching from TX back to RX? It is very >apparent on the waterfall in the digital modes, and anyone running any >digital mode would immediately see this frequency change. I amusing a >typical power supply, and see this change, let's remember, even at the >5W TX level.
Maybe your power supply changes a bit more? Maybe the thermal connection between thermistor and the crystal is different? There might be more people than you think that actually experience the same phenomenon (some worse than others, just due to manufacturing variability and different power supplies), just that they operate CW or SSB, where a 10-15 Hz shift probably wouldn't be noticed, most of the time. Just as a general question, what's the temperature coefficient of the 200 MHz oscillator? It could be as much as 1 ppm/degree C, although I think it's less. I rummaged around a bit and couldn't find my copy of the datasheet for the oscillator, and I don't have my test data handy, either. Jim, W6RMK _______________________________________________ FlexRadio mailing list FlexRadio@flex-radio.biz http://mail.flex-radio.biz/mailman/listinfo/flexradio_flex-radio.biz Archive Link: http://www.mail-archive.com/flexradio%40flex-radio.biz/ FlexRadio Homepage: http://www.flex-radio.com/ FlexRadio Knowledge Base: http://kb.flex-radio.com/
