What is the phase noise like on the cheap TCXO? Being on frequency is far from the only characteristic that matters. I did some research on cheap TCXOs for Kenwood radios and found truly awful phase noise and lots of spurs above and below the oscillator frequency. I don't know if these characteristics are important for your unit.
One eBay source says -125 dBc/1kHz. (Should be stated as -125 dBc/Hz @ 1 kHz). That is not very good. I found the cheap TCXOs I tested actually had worse phase noise at 15 - 20 kHz offset. Mark W7MLG On Feb 8, 2018 4:24 AM, "Thomas Allgeier" <[email protected]> wrote: > Hello All, > > This is for the medium-precision nuts amongst us. I have invested £14.50 > in one of these Vanguard 0.1ppm TCXO's to pimp my Siglent FG which has a > footprint for it. It is its internal ref at 25 MHz. The swapping-in was > simple to do and the FG works fine with it. Since it has a counter mode I > did a quick check to show whether it was worthwile: I made it count the 10 > MHz from my Proteus GPSDO. The Siglent reads to 1 Hz and straight after > turn-on it went straight to 10.000000 MHz. Over about 1 day I never saw it > more than +/-1 Hz off, and this involved a deliberate temperature change of > just over 5 deg C, basically by having the heating in the room off and on. > For most of the time the display sat solidly at 10.000000. > > So, to summarise, in a rough sort of way the thing lives up to its 0.1ppm > spec, at least around the 20C temperature mark. I bought it from a Hong > Kong seller on Ebay - naturally there is always a chance that other devices > sold with the same description/label might not perform as well. > > I'm quite aware that the generator (DDS) suffers from other sources of > error, which won't be improved by the clock being better, but at least the > nominal frequencies it outputs are now going to be very close to the mark > without the need for an external ref. > > Kind regards, > > Thomas. > > _______________________________________________ > time-nuts mailing list -- [email protected] > To unsubscribe, go to https://www.febo.com/cgi-bin/m > ailman/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.
