Hi > On Nov 17, 2014, at 7:48 PM, Charles Steinmetz <csteinm...@yandex.com> wrote: > > Bob wrote: > >> The 58503 is a Z3801 with a pretty instrument style package put around it - >> right? >> >> If so, it might / should have a 10811 in it rather than an MTI OCXO. > > I think there may be other minor differences between the 58503 and the Z3801, > including a newer GPS engine, but I'm not positive what they all are. They > are clearly very similar. > > The 58503 should have either a dual-oven 10811 or the Symmetricom look-alike. > (The Symmetricom has a 5MHz crystal and a doubler -- it looks exactly like a > DO 10811 except for lacking an HP sticker.) I bought a 58503 from one of the > usual far-eastern suspects, which was advertised expressly as having a 10811. > When it arrived, I saw that it had the Symmetricom OCXO. I fired off a > message to the supplier complaining that I did not receive the promised > 10811, and he offered to part-refund the purchase price or exchange the > oscillator. Because of the high transaction cost of exchanging, I elected to > take the part refund thinking I would swap in one of the DO 10811s I had on > hand. But after only a week of running, the Symmetricom was better than all > of the 10811s I own!
It’s the -155 to -160 dbc / Hz phase noise limit that can be tough to hit with a 5 MHz doubled to 10 MHz. Getting below -166 dbc / Hz at 100 Hz offset on a 5 MHz is quite unusual. > (Interestingly, my best 10811 is not a DO unit -- it is a SO 10811 that came > out of an HP5345A that was originally part of a 5390A frequency stability > analyzer.) > > Note: My experience should NOT be read as a claim that the Symmetricom > oscillators are better than 10811s. My sample of the Symmetricoms is way too > limited to make any claims. But this particular Symmetricom happens to be a > very fine OCXO. If it’s a 5 MHz it *should* have ADEV that is as good as / better than just about all the 10811’s out there. Bob > > Best regards, > > Charles > > > > _______________________________________________ > 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. _______________________________________________ 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.