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RF signal generator?

Discussion in 'CB Radio Modifications' started by TruckerKevin, Feb 20, 2018.

  1. TruckerKevin

    TruckerKevin New Member

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    I restore old vintage cb radios as a hobby. I don’t make any money doing so. It’s pure hobby. Sometimes I resell them if I already have one in my collection. But I would like to be able to get to the point of being able to do my own alignments, or get things very close. Right now my bench is equipmentless except a soldering station and some tools. I thought I would start by doing receiver alignments. I have a vintage cobra 142 here that has very poor receive.

    After googling countless threads (many on here) it seems that is it not suggested to use a cheap rf gererator off eBay, as I need a steady signal with the ability to inject a 1khz tone. I have seen mention of using a vintage HP model made in the 1980s, these seem to be well over $400 on eBay. But I see little mention of anything else. Is there anything out there that would work for my application that only costs around $100 to $200? Or less lol. I just shudder at the thought of paying so much for something old and used that is a crapshoot at best on wether it works or not.



    I see new Chinese generators that go as low as 100 kHz. But nothing that would work for me. I would be very happy if someone could say “look for xxxxx or xxxx will work”.

    Thanks
     

  2. Tallman

    Tallman W9WDX Amateur Radio Member, KW4YJ EXTRA class

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    You need more than just a signal generator. I have the B&K 200 and 400 If I were to sell those you would have to put up at least $600.00, shipping not included.
     
    rabbiporkchop likes this.
  3. TruckerKevin

    TruckerKevin New Member

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    T

    $600 vintage equipment. Is that all that’s gonna work for this job?
     
    #3 TruckerKevin, Feb 20, 2018
    Last edited: Feb 20, 2018
  4. Tallman

    Tallman W9WDX Amateur Radio Member, KW4YJ EXTRA class

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    Yes and it is calibrated.
     
    rabbiporkchop likes this.
  5. TruckerKevin

    TruckerKevin New Member

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    I think my point has been missed.

    Perhaps I need to reword it.

    I was hoping to find something non vintage and cheaper that would work for my needs.

    I find used old unguaranteed as is stuff on eBay all day long.it is not a matter of me not finding stuff.

    If this is possible could someone please advise me of a solution. If not, then not.

    Thanks
     
  6. Low_Boy

    Low_Boy Well-Known Member

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    For CB a good B & K 2040 would work great. Also the more costly HP 8640 B is a fantastic signal generator. I own both and love the 8640 B. I bought mine from a eBay seller I believe Electronics Revisited. He restores them and sells them and specializes in the 8640 B don't know if he's around anymore.
     
    rabbiporkchop likes this.
  7. Robb

    Robb Yup

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    The Hp 8656B is what I use, since it can also do FM deviation adjustments. Got mine for ~ $250. Good luck finding one at that price - tho; they usually sell for a bunch more. If you like B&K that's fine; but I like Hp gear - except for their scopes. The B&K should do the job just fine and make it happen for ya.
     
    rabbiporkchop likes this.
  8. Klondike Mike

    Klondike Mike Well-Known Member

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    What an eBay seller asks for and what they get are two different things. They ALL ask for the moon but if the item sits on their shelves they start coming back down to earth with their expectations. Make offers when none are asked for. Set up search queries and wait. You'll find something that fits your budget and needs. Eventually. I bought my Marconi 2018 80kHz-520MHz Signal Generator a few years ago for $91. Works good as new.

     
  9. TruckerKevin

    TruckerKevin New Member

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    Lowboy, I was wondering about that model. Thanks. I may spring for that one.

    Robb. I have been reading your posts for quite awhile now and have learned a lot of what I know now, and reflected some of it in this thread. You really attacked your learning curve here.

    Klondike Mike, I recapped this very radio I am referring to with your kit I just got in the other day, thanks. Seems like quality caps. I will be ordering several more kits in the next few weeks for the rest of my radios. I also just watched a few of your YouTube videos today,the one especially about the macrorni and the meter you recapped. Very cool stuff. You guys are all a bunch of smart ones for sure.
     
  10. TruckerKevin

    TruckerKevin New Member

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  11. Robb

    Robb Yup

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    Wouldn't touch it with a 10 ft pole.
    Simply not reliable.

    I'll elaborate:
    They are not stable on any one freq; they drift madly. They cannot regulate the output amplitude of that signal either. Which is also very critical to have stable.

    Keep in mind that when your are aligning a radio, you are holding it up to a gold standard (accuracy at all parameters) so that the radio knows how to interpret its function. Poor test equipment = bad results.

    I've owned one like it since they were made under different branding, in the attempt to bypass spending big $$ for a real unit. Which I ended up doing anyway. Ended up giving it away because I got tired using it for a doorstop. No exaggeration in that statement either; truth.

    Getting set up for the receive aspect of alignment is far more costly than for transmit test gear. A SINAD meter is also needed for a first class receive job. So does the experience and tricks involved/incorporated become very important to know - too. Not easy for a noob; but there is also nothing wrong with getting thrown in the deep end of the pool to learn how to swim - either. I did - with mixed results.
     
    #11 Robb, Feb 20, 2018
    Last edited: Feb 20, 2018
  12. TruckerKevin

    TruckerKevin New Member

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    For the sinad meter I was going to use the pc program.

    I trust your guidance. Looks like if I am going to do this job right I’m spending money. Do they make anything current that does the job, or must it all be vintage?
     
  13. Robb

    Robb Yup

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    I use a PC SINAD program too; but I also bought the isolation xformer/cables to ensure removal of any grounding problems.

    Dunno a thing about new units from China. Maybe? Perhaps someone else can weigh in on that. If it were me starting out all over again; then I'd go with gold standard test gear.
    Fluke, Tektronix, Hp, etc . . .

    What I use:

    Tektronix 465/100mhz oscilloscope
    Fluke 1900A/80mhz freq counter
    Hp 5316/1ghz freq counter
    Hp 8656B/1.2ghz sig gen
    SINAD program on homebuilt PC running Win Xp/SP4 (32" widescreen to see schematics and alignment data. Also run a program call 'touchstone' for checking the 54mhz harmonic with a SDR dongle)
    UNI-T UT61E multimeter
    Craftsman 82344 multimeter
    Autek Research WM-1 wattmeter.
    Goldline 100w dummy load
    ProsKit MT-5110 cap tester
    MESR-100 Cap ESR meter
    13.8v fixed power supply/20A
    1-20v variable power supply/30A
    26" x 20" anti-static workpad
    10mhz Rubidium standard clock (accurate within +/- .1hz; used to set freq counters right on the money)
    Weller TC202 solder station.
     
    #13 Robb, Feb 20, 2018
    Last edited: Feb 21, 2018
    Shadetree Mechanic likes this.
  14. TruckerKevin

    TruckerKevin New Member

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    You must have a nice shop setup. That is a lot of good equipment. I saw the history of your posts here while googling all of this, it looks like you have really come far.

    I think I might take KlondikeMikes advice and set up an eBay search, and make offers for this stuff over time. Rome wasnt built in a day I suppose.

    I still need an oscilloscope as well. Looks like I can get an old analog one pretty cheap on eBay as well
     
  15. Robb

    Robb Yup

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    I'm not a tech; just a hobbyist. I seem to be getting the job done for others as well as my own gear.
    Feels like far.
     

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