3 4-125a for a 2 meter amp

Discussion in 'Amateur Radio Amplifiers' started by AA7QQ, Jun 4, 2015.

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  1. AI6KX

    AI6KX Ham Member QRZ Page

    Thanks for the replies. I'm not home now but I'll check my 1964 Handbook next week to see if I can find that 2M amp.
    I'm thinking now of making the amp for 6 meters, which might be a more interesting band for me out here in the ocean. (I can work what I want locally on FM with a HT.) I have about 10 watts drive available from a transverter on 6, so I could make it grounded-grid.
    Also looking for a schematic to use an 832A or 829B on 6 or 2. I had an 829B rig for 2 meters as a kid. It was a commercial deck that used tuned lines for the plate circuit, maybe a 2E26 driver?

    Steve
     
  2. AI6KX

    AI6KX Ham Member QRZ Page

    OK! I did a small adjustment of the time machine, and found what I need in a 1957 ARRL Handbook. They sure built some pretty rigs back then. Dunno where I'll ever find butterfly capacitors though.
     
  3. WA7PRC

    WA7PRC Ham Member QRZ Page

  4. AI6KX

    AI6KX Ham Member QRZ Page

    Thinking of something more suitable for VHF actually.
     
  5. WA7PRC

    WA7PRC Ham Member QRZ Page

  6. AI6KX

    AI6KX Ham Member QRZ Page

    Nothing, but they seem to be meant for HF magloops. I think I can use a regular split-stator cap in the amp I am looking at, 30 pf/section double-spaced. Those should turn up fairly often.
     
  7. WA7PRC

    WA7PRC Ham Member QRZ Page

    I prefer to not assume stuff, especially when I have no other viable choices, and it's so easy to contact the seller. In one of his many ads, he states that he can build to suit. He shows a 100pF air variable in this video:

    And he states:
    10-100pF/5KV HOMEBREW AIR VARIABLE CAPACITOR KITS
    for yours KW RF amplifier and antenna tuner or magnetic loop antenna

    The plates are manufactured using a CNC machine
    The rotor has 4"OD.
    The aluminum spacer are
    OD = .500 (1/2") 12.7mm ID = .257 6.53mm L = .500 (1/2") 12.7mm

    I can build for u any air variable capacitors ,butterfly capacitor,single and split stator capacitor kits, parts

    I have also available for ham radio BUTTERFLY CAPACITOR KITS

    3" OD ROTOR + 2 STATOR PLATES $ 5.00
    4" OD ROTOR + 2 STATOR PLATES $ 6.50
    5" OD ROTOR + 2 STATOR PLATES $ 7.75
    6" OD ROTOR + 2 STATOR PLATES $ 8.75
    8" OD ROTOR + 2 STATOR PLATES $ 10.50
    10" OD ROTOR + 2 STATOR PLATES $ 14.00

    73 de VA6POP
    yo5bzz(at)gmail.com

    Bryan WA7PRC
     
  8. KH2G

    KH2G Ham Member QRZ Page

    I agree with WB2WIK in getting 3 in parallel to go on 2 meters. The tubes are okay but lead length etc etc is going to be a problem. Why not build with 1 as that will work fine. You can then think if you really want to try m,ore but you'll have a ton of problems guaranteed. Enjoy KH2G
     
  9. AI6KX

    AI6KX Ham Member QRZ Page

    That''s what I decided to do with my 4-65As. One single-tube deck for 2 and one for 6. I am only allowed to run 100 watts out anyway. Maybe I'll throw in a pushpull buffer just to use the 832A.
     
  10. W0AAT

    W0AAT XML Subscriber QRZ Page

    Just confused me at only allowed 100 watts? On 6& 2 all technician and above licensees are allowed legal limit...
     

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