As unhappy as you may be to hear it, Mike, you're done upgrading, at least for now. Thunderbolts are about as good as they get. Yes, some units like the HP and Jackson Labs clocks can do somewhat better, and with entirely-different equipment, you might be able to tell. Not with the 49xP analyzer, though.
Your 497P is limited by its 1-Hz counter LSD, not the Thunderbolt. 1E-10 accuracy from the Thunderbolt is 1 Hz at 10 GHz, and that's about what the Thunderbolt does at tau=1s, even though the spec sheet shows it closer to 1E-9 at t=1s. That means that there is no conceivable benefit to further upgrading the 10 MHz reference beyond where you already are. I know, I know, that's the worst news of all. :) Focus on giving the Thunderbolt the best signal you can, via antenna mounting. -- john, KE5FX > -----Original Message----- > From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] > Behalf Of Michael Baker > Sent: Sunday, January 27, 2008 8:17 AM > To: time-nuts@febo.com > Subject: [time-nuts] Best choice for house 10MHz reference...?? > > > Hello, All-- > > RE: Tom Van Baak's comments on his preference for a CNS-II > for long-term, high -accuracy UTC measurements (against > Cs or maser) included the statement: > > > I don't use a GPSDO. Instead I use a plain, non-disciplined > > OEM GPS board or something like a CNS II" > > (http://www.cnssys.com/cnsclock/CNSClockII.html). > > > High-end, short-term, or low phase noise, you always use > > quartz; long-term you always used GPS. The cool thing about > > a GPSDO is that you get (almost) the best of both in one box. > -------------------------- > > This got me to wondering.....: > > My primary need for a GPSDO is as a 10MHz house frequency > reference to externally lock my spectrum analyzer up with. > I currently have a Trimble Thunderbolt running and it seems > to be working OK-- > > Is this a good choice for a 10MHz long-term frequency > reference that does not require hocking my wife's > car to pay for...? (she might notice if I did that...) > > I will be a happy camper if I can reliably measure up > to the upper frequency limits of my Tek 497P/494P (21GHz) > to within +/- a few hundred Hz... > > Any feedback on this will be most appreciated!! > > Mike Baker > WA4HFR > Micanopy, Florida > > _______________________________________________ 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.