Certainly in the 1 in 10E9 region a scope is fine. Set the scope to trigger on the 1 PPS and look at your local 10 MHz at 10 or 20 nS/div. A storage or DSO scope makes this pretty easy. You can tweek your local osc pretty quickly this way. At 10 nS/div a 1 in 10E9 walks 1 div in ten seconds.
FWIW, -John ================= > Well, my 8662A I believe has an 10811A in it. Hard for me to imagine that > I > would be able to see this drift on the scope? But I've never thought about > it so maybe I need to think more! But I don't mind spending a bit of $ to > avoid the periodic scope-based calibration process to adjust. Although > granted, the scope approach seems pretty benign. I'll have to research > this > approach more. > > > > 73 Eugene W2HX > > > > From: Robert Atkinson [mailto:[email protected]] > Sent: Friday, November 26, 2010 11:47 AM > To: Eugene Hertz; Discussion of precise time and frequency measurement > Subject: Re: [time-nuts] ok, newbie questions > > > > > Hi Eugene, > > From your comments and equipment list I guess you are looking for low > noise > and stability rather than absolute accuracy. In this case I'd go ro a > 10811 > OCXO. Check to make sure none of you existing equipment doesn't have one > already They were commonly fitted as high stab options. For calibration > you > can use a GPS with 1PPS output. The Timing versions are best. A quick > check > shows Resolution T's and Oncore timing boards available on ebay. There are > also integrated antenna / receivers (HP/Symmetricom 58534A ) for under > $50. > You also need a 'scope. Triggger the scope from the 1PPS. Monitor the OCXO > output and adjust for zero drift across the screen. > Next up you will want to look a TBolt ;-). > > > > Welcome to the Nuthouse! > > > > Robert G8RPI. > > > --- On Fri, 26/11/10, W2HX <[email protected]> wrote: > > > From: W2HX <[email protected]> > Subject: [time-nuts] ok, newbie questions > To: [email protected] > Date: Friday, 26 November, 2010, 4:48 > > Hi all, I am sure my questions have been asked before. Unfortunately, the > mailman style archives are so hard to search through. So forgive me my > transgressions. Happy will I be to get a reference to an old thread that > answers my questions. Don't need new answers if old ones suffice. (of > course > new answers always welcome!) > > I am looking for a 10 MHz standard for my lab. Accuracy/stability > probably > wouldn't make a hill of beans difference in the stuff I do, so my > questions > are more academic and it's just nice knowing I have a "really good" > standard. > > 1. So from reading about this topic on KE5FX.com I understand that a > better > ocxo makes for better phase noise and near-term quality. I also > understand > that some later tbolts had a very good ocxo in them and therefore would > not > benefit significantly from an upgrade as ke5fx did using an HP 10811 unit. > I am considering a thunderbolt advertised on ebay by "flyingbest." I will > be > traveling to China (mainland, and Hong Kong) on business the last two > weeks > in December so I might save some shipping. Here is a photo. Can anyone > tell > me if this unit has a "better" 10811-class ocxo or "not so good "ocxo? I > also understand that not all ocxo's are created equal, even if they are > the > same model number. > > http://tinyurl.com/2dg2dz3 > > 2. Other GPS DO units seem to differ on the number of satellites they can > receive from simultaneously (channels). What is the net effect of having a > standard that can see 6,8 or 16 birds? Is noise averaged out? Is > stability/phase noise improved? Here is an example of a 16 sat unit. > Anyone > have any experience with this unit? Good/bad indifferent? It seems they > can > be had for about $200. > > http://tinyurl.com/2ad5kls > > 3. And then there is the venerable HP units like this one. I understand > this uses the 10811 ocxo. Other than the better ocxo, is there anything > inherently superior about these HP units to warrant the additional cost? > Or > are we mostly just paying for the HP name? This one is 6 sats. > > http://tinyurl.com/24tkwdv > > Lastly, my use of a 10 MHz standard will be for use in equipment like > microwave counters (EIP 548A), Spectrum analyzers (HP 8658B) VNA's (HP > 3577A, 8753C to 6 GHz), synthesizer (HP 3326A and HP 8662A), premium > receivers (Harris 590H), etc., etc. For these purposes, is a GPS DO > advised, > or perhaps a rubidium standard? For example, I don't need this to power a > clock. Just a good, clean, stable signal with low noise, low spurs, etc. > > What's the overall opinion? THANKS !!!! > > (here's to hoping this message looks better than the first two tests I > made) > 73 Eugene W2HX > > > > > > _______________________________________________ > time-nuts mailing list -- [email protected] > <http://uk.mc271.mail.yahoo.com/mc/[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.
