Hi, bought myself a hp 53131a from that well known auction site... didn't pay a lot for mine either, the only thing that was missing was the carrying handle. Went and bought internal ocxo for it, with a trimble oscillator and it's a superb performer! Also have a trimble thunderbolt gpsdo in my workshop (the gold can model). Happy days 👍
Yes they are a superb counter, & since putting in a new over controlled time base, has only drifted by a few mHz in roughly eight Months! I check it occasionally against the gpsdo
Nick, that is a very nice counter! The simplicity of calibrating was awesome! I thought you'd have to bust out the twiddle sticks! BTW, it did look like there was a screw cover on the oven for maybe a finer adjustment....but at just a few hertz...I'd be happy. Great video! ~Jack, VEG
Thanks, yes I was very lucky to get it & the usual hp quality. No twiddling on this counter all done in software! I just hope it never goes wrong as the service manual has no schematics, you're supposed to send a faulty board back to hp for replacement.regards Nick
@@VintageElectronicsGeek thanks for that link, that would be an excellent upgrade to the Crystal oven in my counter, but as I'm using a gpsdo as my external reference from a gpsdo most of the time, it's not really needed in my case, gpsdo are really great, they are a cheap option around $100 that provide amazing accuracy that was unheard of a few years ago unless you had several thousand $ to spend!
Well, I tried! :) I recently picked up a 10 MHz TCXO for $8 I believe...I was very surprised at how spot on it was. The next item I plan on picking up will be a GPSDO, as I am learning electronics I see I need one. ~Jack, VEG
@@VintageElectronicsGeek yes watched your video on that, they really are not stable enough for anything exempt a low resolution counter but hey you get what you pay for! these days GPSDO is the only way to go!
WARNING: this video may contain great knowledge and get you the urge to sit in your best sofa with a blanket and a cup of nice coffee. Viewers discretion advised!
You can grab a few decimals better by using stats and cranking the number of samples little by little. Also pretty important to keep the angle of the device constant after cal.
Thanks I will have to try that sometime. Yes I'm very much aware of the affects of gravity on the OCXO. By the way since calibration about 2 years ago the higher quality OCXO I installed has remained completely stable at about 5 mHz error compared to the gpsdo despite being power cycled several times due to power being off a few times
It's a long time since I did that video, so my memory is not good. But the problem is I think it's only got I think a 14 bit DAC so it's never going to be perfect and we're taking about milli Hz resolution here! Also the installed time base was not the ultra high stability version. I installed a better one in another video.
