Hi > On Nov 27, 2014, at 8:05 PM, Don Latham <[email protected]> wrote: > > I’ve just replaced the SR620 oxco option 01 with a Morion, by simply adding a > 7812 to the 15 v heater feed. Locks well with either gpsdo or cesium external > source. Don’t forget to turn on the external option and set the frequency for > 5 or 10 MHz. It took about 5 days for the Morion to reasonably settle down. > I agree about the Rb, has to be set with Gpsdo anyway, and I’ve already had > 2 of them go South.
I’ve had much better luck with Rb’s once I started heat sinking them properly. I pretty much ignored that issue early on and would regularly loose them. So far I have not lost one with a decent heat sink (and sub 40C baseplate). Without heat sinking, some of them are up around 60-70C on the baseplate. Internal temps are even higher. Bob > > Prescalers from RFBay. > > Don > >> On Nov 27, 2014, at 4:25 PM, Brooke Clarke <[email protected]> wrote: >> >> Hi David: >> >> For me the key benefit of the SR620 is the 16 digit display. That implies a >> lot of digits in the reference (although not all 16 of them) so I always use >> an external reference. >> >> When I turn the PRS-10 upside down the crystal changes frequency and the Rb >> corrects the crystal, see: >> http://www.prc68.com/I/PRS10.shtml#Accel >> http://www.prc68.com/I/Images/FC_ROT.jpg >> >> Mail_Attachment -- >> Have Fun, >> >> Brooke Clarke >> http://www.PRC68.com >> http://www.end2partygovernment.com/2012Issues.html >> http://www.prc68.com/I/DietNutrition.html >> Dr. David Kirkby (Kirkby Microwave Ltd) wrote: >>> On 27 November 2014 at 22:15, Brooke Clarke <[email protected]> wrote: >>>> Hi David: >>> Hi Brooke >>> >>>> If you look just to the right of the SR620 you will see a separate box that >>>> contains the PRS10. >>> Ah, I missed that!!! >>> >>> I was thinking it fitted inside the SR620, but obviously not. >>> >>>> The PRS10 can work as either a Rb GPSDO or as a time stamping device. For >>>> the SR620 any GPSDO would make a good external reference. >>> It would have been nice to have a better reference inside, as >>> sometimes I move equipment around, and don't always want to take more >>> than necessary, so having a better reference inside would have been a >>> nice thing, but I see it is not what I thought. >>> >>> This unit I purchased has the option 01, the ovenized VCXO, but of >>> course that is not going to have the long-term stability of a Rb >>> source. >>> >>> I see one of the SR625 add-ons on eBay, >>> >>> http://www.ebay.com/itm/STANFORD-RESEARCH-SYSTEMS-SR625-2GHz-PRESCALER-/281486714451?pt=US_Marine_Aircraft_Radios&hash=item4189ea6653 >>> >>> but it does not look in good condition, so I'm not paying $700 for it. >>> >>> Dave >>> _______________________________________________ >>> 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. >> > > > _______________________________________________ > 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.
