For what it is worth, can it be a soundcard related problem?
" I should have mentioned before that I did indeed test with the AFC on and off in both sound card programs (MixW and Digipan), no difference in the drift was seen in any case, still a few tens of Hz. " (Brian K7RE) As I understand it, its only a small drift, Some odd things in a soundcard could maybe change the actual clock frequency a bit just after switching between TX and RX, This could result in a small change in the soundcard output frequency and so in the transmitted signal Just a thought, I hope not to send anyone in the wrong direction Happy 2007 pa0pvn (70 minutes to go 2006) groeten Peter petervn(a)hetnet.nl <mailto:[EMAIL PROTECTED]> ; pa0pvn(a)hetnet.nl <mailto:[EMAIL PROTECTED]> ; pa0pvn(a)gmail.com ; pa0pvn(a)amsat.org . ________________________________ Van: [EMAIL PROTECTED] namens Jim Lux Verzonden: zo 31-12-2006 22:18 Aan: Brian Kassel; Ross Stenberg CC: [EMAIL PROTECTED]; flexradio@flex-radio.biz Onderwerp: Re: [Flexradio] More Strange Frequency Drift Problem At 12:22 PM 12/31/2006, Brian Kassel wrote: >Hi Ross: > > As I had mentioned in 2 messages to Tim: > > "I also got a reply from Ken, N9VV. He basically agrees with you, and >I gladly accept the turn on drift, no problem. I stand informed and >educated by you both, thanks! > > What does bother me though is the drift that occurs for about 2 >seconds after going from TX to RX. This same amount of drift happens no >matter what power level is run, and no matter for what time period the >transmission occurs. Makes for tough operating in a digital mode >contest, which is my main operation here. I have never seen this >mentioned on the Flex reflector. Owing to the fact that the drift >amount and time to stabilize remains the same, it doesn't seem like any >temperature related phenomena. If this is inherent to normal operation >of the SDR-1000, then it would appear that either the K2WS mod, or the >GPS mod may be in order. I really want to be sure though before I spend >the big bucks, that there is no other alternative. " > >" I should have mentioned before that I did indeed test with the AFC on >and off in both sound card programs (MixW and Digipan), no difference in >the drift was seen in any case, still a few tens of Hz. " > > So even accepting the short initial turn on, I am still saddled with >the TX-RX drift. Also, I am not totally sure that going with the K2WS >or GPS mod, the TX-RX drift will be cured. Still open for any ideas! Something weird is going on. There shouldn't be that much change in the frequency just changing from Tx to Rx and back. Is your power supply voltage varying (although, I think the XO runs off a regulated 5V)? Is the frequency change a "step" change or a slow drift to a new steady state (where slow is a couple seconds).. My SDR1000s (old ones, no thermistors) drift on initial power up, but are rock steady shifting between Tx and Rx. James Lux, P.E. Spacecraft Radio Frequency Subsystems Group Flight Communications Systems Section Jet Propulsion Laboratory, Mail Stop 161-213 4800 Oak Grove Drive Pasadena CA 91109 tel: (818)354-2075 fax: (818)393-6875 _______________________________________________ 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 <http://www.flex-radio.com/> -------------- next part -------------- An HTML attachment was scrubbed... URL: http://mail.flex-radio.biz/pipermail/flexradio_flex-radio.biz/attachments/20061231/2fa15842/attachment.html _______________________________________________ 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
