Hi Are you interested in 24 hour stability or something longer than that?
Bob On Sep 22, 2010, at 1:42 AM, Lester Veenstra wrote: > > > > > From: [email protected] [mailto:[email protected]] On Behalf Of David > Sent: Tuesday, September 21, 2010 10:55 PM > To: [email protected] > Subject: [qs1r] Looking for good, cheap, external reference > > > > > > Hi, > > I'm interested in doing some ionospheric research, but I don't want to break > the bank with an $8,000 USD GPS disciplined Rubidium clock. > > Anyone have some ideas on cheaper alternatives? The QS1R, and the Flex-3000, > both use a TCXO and they have pretty good long-term stability, but there is > a 1-2 Hz wander at 10 MHz imposed on the frequency over a duration of about > 45 minutes to one hour. It looks like an exponential rise to one limit, > followed by an exponential decay to the opposite limit. > > For long term stability, it obviously requires a temperature stabilized > environment, but I have observed a slow diurnal variation in the TCXO mean > frequency of about 1-2 Hz at 10 MHz just sitting on my desk, exposed in the > morning to some brief sunlight. > > For comparison, my old Icom 756ProIII looks astonishingly stable, but with a > fixed frequency offset of around 0.8 Hz (the best I could do by tweaking the > pot on the PLL). At most I see a very slow diurnal wander of around 0.5 Hz > at 10 MHz. Whatever Icom did, they did it very well. > > - de N7AIG > > __._,_.___ > > Reply > <mailto:[email protected]?subject=looking%20for%20good,%20cheap,%20external%20 > reference> to sender | Reply > <mailto:[email protected]?subject=looking%20for%20good,%20cheap,%20extern > al%20reference> to group | Reply > <http://groups.yahoo.com/group/qs1r/post;_ylc=X3oDMTJxcXF1czR1BF9TAzk3MzU5Nz > E0BGdycElkAzIxNDM0NTE1BGdycHNwSWQDMTcwNTA2MzEwOARtc2dJZAM2OTAyBHNlYwNmdHIEc2 > xrA3JwbHkEc3RpbWUDMTI4NTEwNjk2MA--?act=reply&messageNum=6902> via web post > | > <http://groups.yahoo.com/group/qs1r/post;_ylc=X3oDMTJmcW43cmY3BF9TAzk3MzU5Nz > E0BGdycElkAzIxNDM0NTE1BGdycHNwSWQDMTcwNTA2MzEwOARzZWMDZnRyBHNsawNudHBjBHN0aW > 1lAzEyODUxMDY5NjA-> Start a New Topic > > Messages > <http://groups.yahoo.com/group/qs1r/message/6902;_ylc=X3oDMTM1bmNjNWZkBF9TAz > k3MzU5NzE0BGdycElkAzIxNDM0NTE1BGdycHNwSWQDMTcwNTA2MzEwOARtc2dJZAM2OTAyBHNlYw > NmdHIEc2xrA3Z0cGMEc3RpbWUDMTI4NTEwNjk2MAR0cGNJZAM2OTAy> in this topic (1) > > Recent Activity: > > . > <http://groups.yahoo.com/group/qs1r/members;_ylc=X3oDMTJnc2lrMmdzBF9TAzk3MzU > 5NzE0BGdycElkAzIxNDM0NTE1BGdycHNwSWQDMTcwNTA2MzEwOARzZWMDdnRsBHNsawN2bWJycwR > zdGltZQMxMjg1MTA2OTU5?o=6> New Members 10 > > > <http://groups.yahoo.com/group/qs1r;_ylc=X3oDMTJmbWZ2b3BhBF9TAzk3MzU5NzE0BGd > ycElkAzIxNDM0NTE1BGdycHNwSWQDMTcwNTA2MzEwOARzZWMDdnRsBHNsawN2Z2hwBHN0aW1lAzE > yODUxMDY5NTk-> Visit Your Group > > > <http://groups.yahoo.com/;_ylc=X3oDMTJlYWxqazRmBF9TAzk3MzU5NzE0BGdycElkAzIxN > DM0NTE1BGdycHNwSWQDMTcwNTA2MzEwOARzZWMDZnRyBHNsawNnZnAEc3RpbWUDMTI4NTEwNjk2M > A--> Yahoo! Groups > > Switch to: > <mailto:[email protected]?subject=change%20delivery%20format: > %20Traditional> Text-Only, > <mailto:[email protected]?subject=email%20delivery:%20Digest> > Daily Digest . > <mailto:[email protected]?subject=unsubscribe> Unsubscribe . > <http://docs.yahoo.com/info/terms/> Terms of Use > > . > > > <http://geo.yahoo.com/serv?s=97359714/grpId=21434515/grpspId=1705063108/msgI > d=6902/stime=1285106960/nc1=1/nc2=2/nc3=3> > > __,_._,___ > > _______________________________________________ > time-nuts mailing list -- [email protected] > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
