Joe It is not clear to me what your goal is. Simplicity, cost or performance. A PLL based on 1 pps is not optimum. I call this approach GPSPLL versus GPSDO. Thanks to work done by Karen in Moscow I found out that you can program a $14 ublox M7 to frequencies above 1 KHz. If you use 200 KHz for 5 MHz XO and 400 KHz for 10 MHz you can make a GPS PLL with one 390, one 86 and an op amp. If the XO output is sine wave you have to add a Schmitt Trigger. I recommend Wenzel, AC14 or SN75176. I prefer 75176 it is 8 pin DIL. I do have a board layout if interested. Our Australian team members will introduce it to the HAM community. Not exactly a time nut product. We have done a GPSPLL using a M7 at 1 KHz and tests show better than 1 E-10 at 1 second after 10 seconds GPS takes over it gets better following GPS performance. I have a few boards and op amps left over if interested contact me off list. Bert Kehren In a message dated 11/11/2014 1:05:49 A.M. Eastern Standard Time, jgray@zianet.com writes: > You can run at 400 KHz by dividing by 5/5 and 4/9. True. Either will work. > You said "0.2ppm stability". What do you need for accuracy and/or how are you going to calibrate your setup? I will initially calibrate the OXCO against my HP GPSDO. Idealy, it will only need checking against the GPSDO once a year. Is that asking too much for it to be stable over that length of time? I could simply look up the specs for the various models that I find on ebay. However, I know that a lot of the stuff that is sold has been through the mill and may not meet spec any more. Thus my request for recommendations for models that someone here has actually purchased and tested. Joe Gray W5JG _______________________________________________ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.