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Thread: Motorola S1075C with optional S1079B unit/ ham cb radio - $300

  1. #1
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    Default Motorola S1075C with optional S1079B unit/ ham cb radio - $300

    Not my sale. I put it here because it is VINTAGE:

    I am putting this out for the hard core collector (I know my own limitations) . It is a "service monitor" of sorts and it appears to work and frankly might have some utility left for a newbie. It is not my listing, nor do I know the seller. Hoping it finds a home here on CS. It would be a shame to see it gutted for the NIXIE tubes.

    Link to Craigslist ad far below.

    https://images.craigslist.org/00H0H_...l2_600x450.jpg

    QUOTED TEXT FROM CRAIGSLIST:

    "The Motorola S1075C with the optional S1079B plug-in unit which thus turns this into a Motorola model S1078B according to the instructions.

    This item is a Frequency meter, Deviation monitor, and Frequency Synthesizer.

    The item has been equipped with the optional S1079B plug in unit which appears to be a set up from the optional S1079A unit. Someone has written on the manual indicating that this optional plug-in unit cost $725 back in 1968.

    Testing: Besides moving all controls, the following tests were also preformed.
    Unit self test was done and it passed. See picture.
    I checked the frequency readout on my $90 TYT MD-380(not included) and the unit showed that the 380 was a couple of cycles off. I ran this test in analog using both the 2 meter and the 440cm. Both tests revealed the frequency that the TYT-380 was transmitting on was a couple of Hz off. I did not give the MD-380 any warm up time. I simply turned it on and then went right into transmit.

    I have no idea how to test this unit further but it does appear to be working as it should.

    What’s included:
    S1075C Digital Frequency Meter with instructions
    S1079B Deviation Monitor / Frequency Synthesizer optional plug-in unit with instructions.
    Factory carrying case with handle.

    The following items were stored with the unit so they are included as well.
    S1079A Deviation Monitor / Frequency Synthesizer (instructions)
    One 18 inch coax jumper which has male BNC’s on each end. Coax on this jumper states Amphenol RG-58A/U.
    One 9 inch coax jumper which has male BNC’s on each end. Coax on this jumper states Amphenol RG-58A/U.
    One 11 inch BNC female terminated coax with an open end(possibly used as a shortened antenna???). Coax on this jumper states Amphenol RG-58A/U.
    One BNC terminated wire antenna.
    One Filter model SFE6200A.

    Asking $300 OBO or up or down trade for ???(HF radios, 4' box blade, etc.) "


    https://tampa.craigslist.org/psc/ele...981676075.html


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  3. #2
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    Default

    Gotta love the NIXIES
    K1ngfish

    Supreme and Exalted leader of the Mystic Knights of the Sea

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    Avery Johannssenn (Oct 10, 2019),Radio Tech 64 (Oct 27, 2019),RFI-EMI-GUY (Oct 03, 2019)

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    Since it is not your Craigslist listing then I assume you won't be offended if I say that this thing is astronomically overpriced. They are not that rare and use unobtainable parts, such as tunnel diodes. Yes, the Nixies are cool, but not $ 300 worth of cool. I paid $ 30 for mine at a California hamfest a few years ago.

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    motorola_otaku (Nov 04, 2019)

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    I don't know if anyone would find this interesting/uselful here but the 1075 is related to a Systron Donner 1038 counter (Motorola contracted SD to make the counter portion). Repaired one a week ago for a friend and was trying to find service info on it (hopefully this saves someone an hour or so of googling). I'm sure this one is long sold by now but my friend picked up his for $15 if anyone is looking for a reference.

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    RFI-EMI-GUY (Mar 30, 2020)

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    Some of this ancient test gear is still useful for the hobbyist and uses cave man technology so can be repaired without firmware concerns. I got my start in the hobby/ business decades ago with a Measurements signal generator and a cheap counter that used a common 3.58 MHz TV reference crystal. I would not recommend spending hundreds for this gear unless you are a museum collector when you can buy an HP 8920B or 8924 for under a thousand.

    Any kind of counter with Nixies is nice and useful because you can always calibrate or run from a GPS derived reference.

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    Same here.
    Started with a Hp sig gen about the size of a small refrigerator.
    "upgraded" to the Motorola branded Measurements sig gen.
    Motorola T1020 Frequency Meter.
    Add the Bird 43, a PL tone generator to connect to the sig gen, Simpson and other trinkets and you could do pretty well.
    Even got a spec an that I can't recall the brand.
    It was huge also. 2 ft by 3 ft and about 4 ft deep.
    Good old days!

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    HP608C or D?

    I started my career in a lab where I was taught to measure receiver intermediation using three of those beasts. Keeping them on frequency was a pain. Thankfully 3 HP8640D generators soon arrived, I connected them all to same reference source and from then on those tests were a breeze. We had an HP distortion analyser for the SINAD,

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    One issue with the Motorola/Systron Donner item is that the counter prescaler uses a bunch of tunnel diodes. I was surprised when I saw that because this is the first time I have encountered them and I am not really sure how to deal with them. The prescaler is the only thing left that I don't have operational and I suspect one or more diodes are toast. I was thinking about just building a new prescaler on perf board using a modern single-IC design and sticking it on the prescaler board after stripping enough original parts to make it fit. I saw my first one of these in 1970 in the local sheriff's communications shop and was very impressed!

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    You can probably find replacements out there. This was the first that popped up. It would be simpler just to fix what worked 50 years ago.


    https://www.ebay.com/itm/Set-10-Tekt...4AAOSwsdJdoQL0

    Quote Originally Posted by WB6NVH View Post
    One issue with the Motorola/Systron Donner item is that the counter prescaler uses a bunch of tunnel diodes. I was surprised when I saw that because this is the first time I have encountered them and I am not really sure how to deal with them. The prescaler is the only thing left that I don't have operational and I suspect one or more diodes are toast. I was thinking about just building a new prescaler on perf board using a modern single-IC design and sticking it on the prescaler board after stripping enough original parts to make it fit. I saw my first one of these in 1970 in the local sheriff's communications shop and was very impressed!