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Old HP freq counter

Discussion in 'Misc Electronics' started by Javier Henderson, Oct 3, 2004.

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  1. 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
     
  2. Phil Hobbs

    Phil Hobbs Guest

    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
     
  3. Michael

    Michael Guest


    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
     
  4. Tweetldee

    Tweetldee Guest

    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!!
     
  5. Clarence

    Clarence Guest

    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.
     
  6. John Fields

    John Fields Guest

    ---
    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.
     

  7. 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
     
  8. was a

    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.
     
  9. John Fields

    John Fields Guest

    ---
    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
    ---
     
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