I used to use an HP frequency counter in the 70's, which measured about 3' by 3' by 3'. It weighed slightly less than a house, it had an incredibly powerful and loud fan, and a removable module. I'm guessing it was made in the 60's. The digital display was made of Nixies.
I've been trying to find photos of this rig for a while, without any luck. I don't even remember the model number.
Help with either URL's to photos of this thing, or the model number, would be most appreciated.
Thanks!
-jav
Was that the one that used a harmonic mixer to get the frequency down to something it could count? I remember using a counter like that way back--you had to twist a tuning knob to select the right LO harmonic. Weird.
Cheers,
Phil Hobbs
I could have suggested a model# 15+ years ago but I've passed the age when CRS (Can't Remember Stuff) set in. :-( Have a mental image of an HP counter I used in the Air Force back in 1969-70 that had a kazillion (more like 15-20) Nixies spread across almost the entire width of the front panel, at top. Used the counter during calibration of HP-5060A cesium beam.
A former A.F. PMEL guy who apprently is the same vintage as I am responded to a post of mine a year or two ago. He might know the naswer to your question. You still around, Sarge?
Michael
That would probably be the HP model 5245L, or one of its cousins. It was a
50MHz mainframe counter, having a variety of plugin modules that carried the counter frequency range from 50MHz into the GHz. There were also time interval plugins, DVM plugins, and several other miscellaneous plugins available. It was certainly the industry standard for a number of years because of its reliability and its stable, accurate time base oscillator (3x10-9 as I remember).I have one of these units in my shack, but rarely use it because of its
50MHz limit and lack of a plugin to make it go beyond that. It is a great unit to use, however, because ot the nice Nixie display.-- Dave M MasonDG44 at comcast dot net (Just subsitute the appropriate characters in the address) Never take a laxative and a sleeping pill at the same time!!
A 5245L was made by HP But the version your looking for, and that I have used was much larger. Not however 3x3x3 feet. More like 28x28 x28 inches. I do not remember the model number so I did not reply sooner. I did use various versions of the 5245 and it was a desktop "Stackable" instrument.
-- The 5245L doesn't meet either the 3'x 3'x 3' envelope or the weight criterion, but the fan noise probably comes close! If I'm not mistaken, that old counter is an HP524CD. Back in those days I was working for Loral Electronics in New York, and we built some ECM test equipment for the air force which had one of them rack-mounted in a test console which was used to align ECM receivers.
John is probably right - I cant remember the model no, but the size/description was right - and from memory it had hundreds (well, a lot) of 12AT7's to do the logic. Cant be sure it used NIXIE readout tho - the one I remember had some other scheme, perhaps lightbulbs/neons behind celluloid windows (possibly raving here, it was a LONG time ago)....I still have (and use) a HP5245L, I have the prescaler to 2.3Ghz, xtal locked to the main timebase oscillator to select harmonics - ovenised xtal, so state of the art then. Beautifully made mechanically, and the service manual was a superb example of "how to write a good manual" - it even has Boolean equations for how it works, so troubleshooting was dead easy. Perhaps its age, but I still find NIXIE tubes easier to read across the room than led's or LCD's.
73 de VK3BFA Andrew
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It can't be a 5245L because they're only 6 or 8 inches high. He's talking about one that's at least five times that size, three feet high.
I have a '73 HP catalog with the 5245L in it, and it's more modern than the one he's talking about. I think the 5245L is all solid state. The old HP counters had a lot of tubes, and a crystal oven for the timebase, so you had to leave it plugged in with the oven turned on all the time to keep the crystal from drifting.
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--- Sometimes you can 'remove the dark' by reading the earlier posts in a thread:
John is probably right - I cant remember the model no, but the size/description was right - and from memory it had hundreds (well, a lot) of 12AT7's to do the logic. Cant be sure it used NIXIE readout tho - the one I remember had some other scheme, perhaps lightbulbs/neons behind celluloid windows (possibly raving here, it was a LONG time ago)....I still have (and use) a HP5245L, I have the prescaler to 2.3Ghz, xtal locked to the main timebase oscillator to select harmonics - ovenised xtal, so state of the art then. Beautifully made mechanically, and the service manual was a superb example of "how to write a good manual" - it even has Boolean equations for how it works, so troubleshooting was dead easy. Perhaps its age, but I still find NIXIE tubes easier to read across the room than led's or LCD's.
73 de VK3BFA Andrew---
-- John Fields
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