Thanks for bringing up phase noise. From my research on other cheap devices (knockoff TCXOs), I have found that phase noise was obviously not considered and in that case was truly awful. It was in the -115 dBc range at 100hz, but, likely due to poor design, actually rose to -110 dBc at 10-100 kHz offset, which is truly awful. There were also many spurs. If something is not specified, it is likely not even considered.
I had not realized a Trimble Thunderbolt was so good. I have been using the output of the low aging rate option of an HP8642A for a 10 MHz reference, no idea of the phase noise. Now you have me wanting something else! 73, Mark W7MLG On Tue, May 9, 2017 at 7:19 AM, Paul Christensen <w...@arrl.net> wrote: > >"If you want a good quality 10 MHz GPSDO, I recommend the one made by Leo > Bodnar M0XER. It was reviewed in QST, June 2016." > > Unless the K3S architecture is different than the K3, then frequency, > rather > than phase-locking is used from the external frequency source. Phase noise > performance of the GPS-DO doesn't impact performance of the K3 receiver. > > However, if planning on distributing the GPS-DO to other devices, I think > it's worthwhile to note that the higher-priced version of the Bodnar is > still > 30 dB worse at a 100 Hz Fc offset than a common Trimble Thunderbolt > with the Trimble-branded OCXO (not Piezo) when powered from a low-noise, > lab-grade supply. For example, typical Trimble PN at 100 Hz is -160 dBc. > The upper-grade Bodnar unit is about -125 dBc. > > Compared to what's available on the new and used markets, I agree with > G4DYA > that the Bodnar's performance is probably characterized as good, but not > excellent. Again, for K3 users it isn't an issue, but if the device is > driving other test gear or other transceivers, that 30 dB difference may > mean a lot. > > The Thunderbolts were once plentiful on eBay for USD $99. Scarcity has > driven that up but with persistence, a watchful eye can still spot one at a > reasonable price. > > I ended up installing a Trimble unit and Lambda linear supply into a > customized enclosure. It drives a TAPR distribution amp and that supplies > a > precision 10 MHz refence to multiple transceivers and test equipment. > > http://tinyurl.com/j7r36w5 > > Paul, W9AC > > > > > > > > --- > This email has been checked for viruses by Avast antivirus software. > https://www.avast.com/antivirus > > ______________________________________________________________ > Elecraft mailing list > Home: http://mailman.qth.net/mailman/listinfo/elecraft > Help: http://mailman.qth.net/mmfaq.htm > Post: mailto:Elecraft@mailman.qth.net > > This list hosted by: http://www.qsl.net > Please help support this email list: http://www.qsl.net/donate.html > Message delivered to marklgoldb...@gmail.com > ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to arch...@mail-archive.com
