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See thru amplifier

Discussion in 'Amplifiers' started by Mudfoot, Sep 27, 2019.

  1. Mudfoot

    Mudfoot Sr. Member

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    357magnum and Shadetree Mechanic like this.

  2. Shadetree Mechanic

    Shadetree Mechanic 808 On The North Side of Dover

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    Might be a nice driver.:whistle:

    s-l400 (15).jpg
     
  3. sunbulls

    sunbulls Sr. Member

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    They have lot more info on the kit version. With some SMT soldering involved, I would be tempted to experiment with one already assembled. Check out the following links. Having a bias adjustment and PTT is a plus. Interesting filter mods for various bands also shown.

    https://www.dk9jc.de/blog/equipment/142-diy-kits-70w-ssb-linear-hf-power-amplifier-ft-817-kx2-kx3

    http://pa-11019.blogspot.com/2016/11/diy-kits-70w-ssb-linear-hf-power.html



     
  4. Beetle

    Beetle Sr. Member

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    Transparent to outgoing RF as well, I'd guess.
     
  5. Ranch55

    Ranch55 Well-Known Member

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    I think it is a bad idea.
    With no metal case, it has no RF shielding ........

    Just sayin' ........
     
  6. KD2GOE

    KD2GOE W9WDX Amateur Radio Club Member

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    [​IMG][​IMG]
     
  7. kopcicle

    kopcicle Sr. Member

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    So how does a MRF 1920 work at 1.8-54MHz ?
    https://www.nxp.com/docs/en/data-sheet/MRF9120.pdf

    @Mudfoot However :) , See the similarities to ...
    board.jpeg


    Anyway I was looking at the board and it seems to be used for not only the MRF1920 but the pair of plastic no name TO-220 devices as well.

    My thought was (is?) to upgrade to 50V components and stuff the MRF101/AN-BN in it and see if I can saturate the output transformer

    minipa_sch.jpeg

    Lowest price I saw was $39 for the TO-220 version . Come to think I may have seen the MRF-1920 for even less recently.

    At those prices I could be easily talked into experimenting. Now if anyone finds just the board (y)(y)(y)(y)
     
    #7 kopcicle, Sep 27, 2019
    Last edited: Sep 27, 2019
    Tallman and Shadetree Mechanic like this.
  8. sunbulls

    sunbulls Sr. Member

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    No, I wouldn’t operate the transparent version as is either. Besides RF issues, those SMA connectors would be replaced with SO-239’s. A metal encasement would take care of both issues. At least having the amp already assembled will save time and possible errors. The Chinese seem infatuated with using SMA on almost everything these days. IMO it’s bad enough they replaced the durable BNC’s with those fragile connectors on HT’s, now their using them on HF. We’re certainly not dealing with 900Mhz or higher. I particularly like the workmanship this guy did with his amp.
    PA 20-70 amp.jpg
     
    bobl9355 and Shadetree Mechanic like this.
  9. Tallman

    Tallman W9WDX Amateur Radio Member, KW4YJ EXTRA class

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    Sounds like a smoked RMItaly amp case would work good as a project box for the see through design.
     
    Shadetree Mechanic likes this.
  10. Tallman

    Tallman W9WDX Amateur Radio Member, KW4YJ EXTRA class

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    I might have some for sale.
     
  11. SIX-SHOOTER

    SIX-SHOOTER Sr. Member

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    The MORON building & selling them does NOT care about anyone but themselves & any result of RF damage to them.It's CHEAP make a quick dollar & Run.

    SIX-SHOOTER
     
    Tallman likes this.
  12. S&W357

    S&W357 WDX-556 Supporting Member Space For Rent

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    So dainty looking.
     
  13. Shadetree Mechanic

    Shadetree Mechanic 808 On The North Side of Dover

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    Could just about bolt it to the back of a radio.....
     
  14. SIX-SHOOTER

    SIX-SHOOTER Sr. Member

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    More like,so dangerous looking.

    SIX-SHOOTER
     
    S&W357 and Shadetree Mechanic like this.
  15. Shadetree Mechanic

    Shadetree Mechanic 808 On The North Side of Dover

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    Someone should make a video of a field strength meter near it.
     
    binrat likes this.

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