Hi Any time you get into something like this, there are a lot of qualifiers on everything. That makes for a number of special cases. Ignoring them and looking at the most likely:
1) Your typical modular Rb will beat your typical good OCXO past a few hundred seconds on short term stability. 2) The same Rb will start to degrade on short term stability past a few thousand seconds. (Curve goes down, levels, and then starts to come back up). 3) GPS it's self starts out pretty awful. It just keeps getting better the longer you look at it. 4) Most good GPS's will get better than most modular RB's between 5,000 and 50,000 seconds. 5) We are talking about radio here. The atmosphere does matter. There are some daily cycles that might push you out past 86,000 seconds for a unit that's stable under all conditions. You could go with an L1/L2 receiver if you have one available. Of course, what matters is "what do the ones I have do" and not what a typical population does. You might select parts that do a bit better than typical. That is likely to involve some measure and adjust cycles. If you toss in a TBolt rather than a simple GPS receiver, it's going to clean up some of the GPS crud for short time intervals. That may or may not help things overall. It's not likely to hurt anything though. That's the overview, there are a whole lot of grubby little details each step along the way. Bob -----Original Message----- From: [email protected] [mailto:[email protected]] On Behalf Of Tim Tuck Sent: Monday, July 11, 2011 9:16 PM To: Discussion of precise time and frequency measurement Subject: [time-nuts] Disciplining a Rubidium with a Thunderbolt. Hi all, Just wondering how many people have used John Miles work @ http://www.ke5fx.com/tbolt.htm, or similar, to discipline a rubidium oscillator and if so... 1. what was the RB of choice ? 2.have any measurements of phase noise etc. been published on such a rig ? 3. Are there any published how-to's etc. available ? I'd like to build such a beast as my lab standard so any help appreciated. thanks Tim -- VK2XTT :: QF56if :: BMARC :: WIA :: AMSAT-VK :: AMSAT _______________________________________________ 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. _______________________________________________ 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.
