> On your rubidium comment, one needs to be a little careful about > expectations. For short tau (say 0.1 to 10 seconds) your average > cheap eBay surplus telecom Rb will have far less performance > than a good OCXO. Yet mid-term (say 10 to 10^4 seconds), a > Rb-GPSDO will win. However, long-term the LO makes much less > difference since GPS always wins. And GPS aside, clearly the > holdover performance of Rb will blow away OCXO. >
Good point, there's a big piece of the curve where simply upgrading a quartz-based GPS standard to drive an Rb would not be a win. Two pieces, actually, since Efratom (at least) doesn't seem to care much about phase noise. > So it all depends on ones need. I guess my main point is that a > typical rubidium-based TBolt is not necessarily, just because it's > "atomic", automatically better than a stock TBolt at every point. > > If you'd like to test an FRS or LPRO version of a TBolt for me let > me know. I'd rather see your plots than my words. I could graft a rubidium source onto the original Thunderbolt platform I used for the OCXO tests, but I currently don't have a good way to look at Allan deviation compared to the TSC/maser setup you've got. I can measure the phase noise easily enough but it'd be better to get it back to you for longer-term tests, especially if the loop parameters need to be adjusted iteratively. That would be a heat-death-of-the-Universe process on a 3048A... -- john, KE5FX _______________________________________________ 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.
