Hi The only reason the check list is any good is the - gee if I'd checked that I would not have bought this one syndrome ...
------------ The same socketed ROMs on the A that have issues while they are "live" are easier to replace if / when they go bad. ------- Many of these counters (any model) spent their life on an external standard. Having an OCXO that's a ppm or two off is not unusual. What you want to watch out for is the one that's 30 or 40 ppm off. Bob On Nov 14, 2010, at 11:15 PM, John Miles wrote: > Bob's checklist is a good one, all right. It is important to get a solid > working example because they are quite challenging to troubleshoot and > calibrate. > > The only problem with the 5370A as far as I'm aware is the reduced > reliability caused by the larger number of socketed ROM chips. > > It seems that many, if not most, 5370s were used with external 10 MHz > references. If you're patient, you can wait for one to show up on eBay with > a display that is blank except for one bright LED. Buy it cheap, and flip > the external-reference switch back to internal-reference mode when you get > it. Easy "fix!" > > -- john, KE5FX > >> -----Original Message----- >> From: [email protected] [mailto:[email protected]]on >> Behalf Of paul swed >> Sent: Sunday, November 14, 2010 8:01 PM >> To: Discussion of precise time and frequency measurement >> Subject: Re: [time-nuts] How does one actually do Allan variation >> graphs? >> >> >> Really good advice on what to checkout. >> 5370s are the devil to fix if somethings wrong such as jitter. >> Good luck. >> Paul >> >> On Sun, Nov 14, 2010 at 12:40 PM, Bob Camp <[email protected]> wrote: >> >>> Hi >>> >>> Like a lot of stuff, the going price for these has dropped. >> They get less >>> and less respect every day ... >>> >>> One thing that may be specific to me - I do not consider a >> 5370A to be any >>> more or less valuable than a 5370B. They both do pretty much >> the same thing. >>> The 5370B might have fewer hours on it, it might not. On average 5370A >>> prices seem to run slightly higher than 5370B prices. Why is a >> mystery to >>> me. >>> >>> Bob >>> >>> >>> On Nov 14, 2010, at 11:57 AM, William H. Fite wrote: >>> >>>> Thanks, Bob >>>> >>>> He's asking $400 but I can tell by the look in his eye that he'll take >>>> substantially less. >>>> >>>> He's a lousy poker player, too... >>>> >>>> I asked him to turn it on about 0900 this morning and I'm >> going over in >>> an >>>> hour or so to check it out. >>>> >>>> Thanks again, >>>> >>>> Bill >>>> >>>> >>>> >>>> >>>> On Sun, Nov 14, 2010 at 11:44 AM, Bob Camp <[email protected]> wrote: >>>> >>>>> Hi >>>>> >>>>> Assuming: >>>>> >>>>> 1) All the knobs and switches are intact and working >>>>> 2) All the led's in the display work >>>>> 3) All the alarm and indicator LED's work >>>>> 4) The input amps are good >>>>> 5) All the connectors are intact >>>>> 6) The OCXO is good / on frequency >>>>> 7) It passes the diags >>>>> 8) Jitter is down below 100 ps ( should be below 40) >>>>> 9) You can check all this out before purchace. Let the beast >> warm up for >>> at >>>>> least an hour before you check it. >>>>> >>>>> Something in the $180 to $260 range is probably fair depending on >>>>> cosmetics. You might start out at $150 in order to >> compromise at $200. I >>>>> certainly would not pay over $300. I know the list sounds a bit long, >>> but >>>>> I've seen 5370's with problems in each of those areas. Pretty much >>> anything >>>>> damaged / non-functional would knock a pretty good chunk off >> the price. >>>>> >>>>> Bob >>>>> >>>>> >>>>> On Nov 14, 2010, at 11:29 AM, William H. Fite wrote: >>>>> >>>>>> Gentlemen, >>>>>> >>>>>> What is a reasonable price for a 5370A? Local guy here is trying to >>> hawk >>>>>> one to me. Not cosmetically perfect but fully operational. >>>>>> >>>>>> Yes, I know someone is going to say, "I got one for 50 bucks." But >>>>> really, >>>>>> what is a fair price? >>>>>> >>>>>> Thanks, >>>>>> >>>>>> Bill >>>>>> >>>>>> >>>>>> >>>>>> >>>>>> On Sun, Nov 14, 2010 at 10:48 AM, Magnus Danielson < >>>>>> [email protected]> wrote: >>>>>> >>>>>>> On 11/14/2010 09:41 AM, John Miles wrote: >>>>>>> >>>>>>>> >>>>>>>> I’ve looked at Wikipedia and I am as lost as when I started. >>>>>>>>> >>>>>>>>> Could someone walk me through the process step by step and also >>>>>>>>> tell me what test equipment is required? >>>>>>>>> >>>>>>>>> >>>>>>>> Besides the pointers at www.leapsecond.com , I've collected a few >>>>> links >>>>>>>> at http://www.ke5fx.com/stability.htm that may be helpful. >>>>>>>> >>>>>>>> The first .PDF link on that page is my presentation from the >>> Microwave >>>>>>>> Update conference a few weeks ago. It was meant as an >> introductory >>>>>>>> "Stability Measurement for Radio Nuts" talk, discussing >> the state of >>>>> the >>>>>>>> commercial art in light of what's available to hobbyists. >>>>>>>> >>>>>>>> The NIST links under "General timing and noise metrology", in >>>>> particular >>>>>>>> this one ( http://tf.nist.gov/general/pdf/2220.pdf ) are >> excellent. >>>>>>>> >>>>>>>> If you have an HP 5370A/B counter and a GPIB interface >> you can do a >>> lot >>>>> of >>>>>>>> good measurement work. With the appropriate software you can make >>>>>>>> conventional strip-chart style plots of frequency and >> phase, as well >>> as >>>>> ADEV >>>>>>>> and similar plots. Unless you are a software nut you >> probably do not >>>>> want >>>>>>>> to homebrew the necessary code to do this. Most people >> don't use the >>>>> same >>>>>>>> program for acquisition and plotting; a script or batch >> file does the >>>>> job of >>>>>>>> reading the data from the counter and spooling it to a text file, >>> while >>>>> a >>>>>>>> program like Stable32 or Ulrich Bangert's (search on >> df6jb plotter) >>>>> renders >>>>>>>> the graphics. >>>>>>>> >>>>>>>> My own app (TimeLab) is an exception, in that it attempts to do a >>> good >>>>> job >>>>>>>> at both data acquisition and rendering. It's still under heavy >>>>>>>> construction. Right now I'm rewriting all of the acquisition >>> routines >>>>> to >>>>>>>> support, among other things, the use of more than one >> GPIB counter at >>>>> once. >>>>>>>> >>>>>>>> Given that you have an HP 5370 available, if you wanted a >>> walkthrough, >>>>> you >>>>>>>> could try something along these lines: >>>>>>>> >>>>>>>> 1) Get an NI or Prologix GPIB adapter, install per manufacturer's >>>>>>>> guidelines. >>>>>>>> >>>>>>>> 2) Download the current TimeLab beta. You have two options here: >>>>>>>> http://www.ke5fx.com/timelab/setup.exe -- Graphically ugly but >>>>>>>> better tested >>>>>>>> http://www.ke5fx.com/timelab/setup_temp.exe -- Nicer looking, >>>>> but >>>>>>>> more likely to have bugs, and some features have yet to be ported >>> over >>>>> to >>>>>>>> the new codebase. Use this one for the instructions below. >>>>>>>> >>>>>>>> 3) Decide whether you want your HP 5370A/B to run in >> talk-only mode >>> or >>>>>>>> addressable mode and set its DIP switch accordingly. The software >>> will >>>>> work >>>>>>>> either way since it doesn't actually try to control the >> counter, but >>>>> for a >>>>>>>> 5370 I'd use addressable mode unless you have a reason not to. >>>>>>>> >>>>>>>> 4) Set up a basic frequency measurement to begin with. >> Feed a 10 MHz >>>>>>>> signal or whatever into the STOP jack, and hit FREQ and 1s. >>>>>>>> >>>>>>>> 5) In TimeLab, select Acquire->Acquire from HP 5370A/B, and then >>> select >>>>>>>> the NI interface or the Prologix interface's COM port >> from the list. >>>>> Hit >>>>>>>> the "Monitor" button and you should start seeing the counter's >>>>> frequency >>>>>>>> readings scroll by. If not, find out why before going >> any further. >>>>>>>> >>>>>>>> 6) Hit "Start Measurement." After a few readings have >> come in, you >>>>> should >>>>>>>> see your ADEV plot start to take shape. >>>>>>>> >>>>>>>> 7) Hit the 'f' key to switch to a frequency-difference >> chart, or the >>>>> 'p' >>>>>>>> key for a phase-difference chart. The 'y' key will >> toggle the Y-axis >>>>>>>> between easy-to-read round numbers and full display range. >>>>>>>> >>>>>>>> You can get somewhat cleaner measurements from the 5370 if you use >>>>>>>> time-interval mode rather than frequency mode, but time-interval >>>>>>>> measurements require a 1-pps or similar source and some additional >>>>> setup >>>>>>>> effort. >>>>>>>> >>>>>>> >>>>>>> 0) Essentially whatever source you have (crystal, Rubidium, Cesium, >>>>> GPSDO) >>>>>>> unless you haven't done it before, turn it on well in advance. I >>> prefer >>>>> days >>>>>>> over hours. Locked crystals such as Rubidium, Cesium and >> GPSDOs will >>>>> cancel >>>>>>> the last part of the oscillator drift but depending on details >>>>> performance >>>>>>> may be more or less compromised by this drift. I think >> this is one of >>>>> the >>>>>>> practical details one should not miss. >>>>>>> >>>>>>> I for one thinks that using a trigger signal such as the >> PPS or more >>>>>>> preferably a higher frequency trigger is worthwhile, as >> you get a more >>>>>>> stable rate of read-outs. Also, it gives a larger amount >> of raw data, >>>>>>> allowing for the increased degrees of freedom and quicker >> convergence >>> of >>>>>>> estimator(s). >>>>>>> >>>>>>> Do use TimeLab, I think it is a great way to get going. >> It's also fun >>> to >>>>>>> see the curve converge as more data comes in... >>>>>>> >>>>>>> Cheers, >>>>>>> Magnus >>>>>>> >>>>>>> >>>>>>> _______________________________________________ >>>>>>> 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. >>>>> >>>> _______________________________________________ >>>> 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. >> > > > _______________________________________________ > 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.
