HI Opening the box to be sure there's not a dead spider in there is always a good idea...
The old oscillators all went out before firmware 3.0. Manufacturing dates past end of 2000 should all have a better oscillator. You could test it for phase noise and short term stability, but pulling the cover is *lots* easier. Firmware rev does show up in software. Anything past 2.1 is fine. The only reason to watch for 3.0 is that's what the e place sellers key into. The temp sensor is the one that moves in real small steps. The bad one moves in (1/2 degree???) big steps. All of that (and much more) is visible if you bring up Lady Heather and see what's going on. Bob On Sep 22, 2010, at 7:58 PM, russell wrote: > Is there anyway to tell without opening the box if you have: > > 1) "better oscillator" (=Trimble labeled) Anything visible from SW > (Tboltmon or LH)? Any behavior fingerprint? > > 2) "newer firmware" (=rev 3.00) Does show up in SW. > > 3) "newer brain dead temp sensor" (= ?). Anything > visible from SW (Tboltmon or LH)? Any behavior fingerprint? What is the > new sensor you changed to? > > Thanks. Russell > > > ----- Original Message ----- From: "Ed Palmer" <[email protected]> > To: "Discussion of precise time and frequency measurement" > <[email protected]> > Sent: Wednesday, September 22, 2010 6:39 PM > Subject: Re: [time-nuts] [qs1r] Looking for good, cheap, external reference > > >> And if you buy a newer unit with the better oscillator, new firmware, and >> newer (but brain-dead) temperature sensor, it's trivial to replace the >> sensor. It took me longer to take the unit apart than to change the chip >> and I don't have a lot of experience with surface mount. >> >> Ed >> >> Bob Camp wrote: >>> Hi >>> >>> That's my feeling. The firmware isn't the issue. The OCXO and the temp >>> sensor are the important points. The firmware is just an easy way to get >>> the right OCXO. >>> >>> Bob >>> >>> >>> >>> On Sep 22, 2010, at 7:00 PM, Mark Spencer <[email protected]> wrote: >>> >>> >>>> Would a newer unit with the 3.00 firmware, the trimble branded OCXO and >>>> the older temperature sensor be one of the better (or perhaps best ?) >>>> TBOLT combinations ? >>>> >>>> >>>> >>>> ----- Original Message ---- >>>> From: John Miles <[email protected]> >>>> To: [email protected]; Discussion of precise time and frequency >>>> measurement <[email protected]>; David <[email protected]> >>>> Sent: Wed, September 22, 2010 12:42:06 PM >>>> Subject: Re: [time-nuts] [qs1r] Looking for good, cheap, external reference >>>> >>>> >>>> >>>>> John, unless I am going mad, the ADEV plots for both auctions you >>>>> mentioned look the same - maybe the bad one has been replaced since >>>>> you posted your message? >>>>> >>>> The black-and-white plot that everybody uses is from the original >>>> Thunderbolt data sheet, which was way conservative even for the older >>>> units. >>>> Towards the bottom of the 290308733659 auction, though, the seller has >>>> appended a half-dozen or so photographs of a TSC 5120A screen showing what >>>> are (for a Thunderbolt) some weak results. The ADEV plot shows poor >>>> long-term disciplining and the PN plot doesn't look good either. Possibly >>>> he's using a noisy reference, or the unit was tested during a 2-day-long >>>> earthquake. >>>> >>>> I've never seen one do ~-88 dBc/Hz at 10 Hz. Even my original one with the >>>> lower-quality OCXO was good for -105 dBc/Hz, while the ones with the >>>> Trimble-labelled OCXO can do -130 or better. Likewise the 'good' ones will >>>> do several dB better than the -150 dBc/Hz broadband floor he shows. >>>> >>>> I've also never seen one in a black anodized(?) housing like that (has >>>> anyone else?) Mark is right in that the 3.00 firmware doesn't necessarily >>>> do much for you, but the newer units also had the good OCXOs, which IMO is >>>> more important than the temp sensor. >>>> >>>> -- john, KE5FX >> >> _______________________________________________ >> 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. > _______________________________________________ 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.
