Choosing antenna tuner capacitor

Discussion in 'Radio Circuits, Repair & Performance' started by 9A5DLZ, Feb 16, 2016.

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  1. 9A5DLZ

    9A5DLZ Ham Member QRZ Page

  2. WA9WVX

    WA9WVX Ham Member QRZ Page

    Who was wondering about TEFLON Sheets? There's a supplier known as McMaster-Carr that sells all forms of Teflon Products http://www.mcmaster.com/#sheets-(made-with-teflon-ptfe)/=11llmzq I've used this company for buying hardware Brass Screws & Nuts, Lexan sheets, Stainless Steel "U" Bolts, practically every thing for homebrewing projects, special tools or what ever I need. I can't believe that other countries don't have industrial suppliers like McMaster-Carr.

    Dan
    WA9WVX
     
  3. 9A5DLZ

    9A5DLZ Ham Member QRZ Page

    There is something like that in Croatia, but It turns out I don't have skills to make capacitors from scratch.
     
  4. 9A5DLZ

    9A5DLZ Ham Member QRZ Page

    I measured today, I will need right about 40m of open wire feedline. Can I use 40m of open wire feedline on 80m, 40m, 20, and 10m? You know, because wave length on 80m is close to open wire length. And it's 2 lambda, 4 lambda, 8 lambda length on 40, 20 and 10m. Should I put 50m of feedline instead?
     
  5. N7EKU

    N7EKU Ham Member QRZ Page

    Hi Mario,

    This depends on your actual antenna. If you are planning on a dipole, then you should check here: http://w5dxp.com/goodbad/goodbad.htm to help you choose wisely.

    Concerning the high-voltage capacitors that you bought. Capacitors also come in RF-specific types. These are assured to have low-dissipation at HF or higher frequencies. With normal high voltage types, you don't know how they will behave until you try them. So once you put them in use, make sure you check them for heating as that would indicate problems with them.

    73,

    Mark.
     
    9A5DLZ likes this.
  6. 9A5DLZ

    9A5DLZ Ham Member QRZ Page

    Thanks, this is very helpful.
     
  7. W7DEX

    W7DEX Ham Member QRZ Page

    Thank you. I've never heard of this before, it solves a major problem I've been trying to solve. Looks like you can't buy these anymore, they have to be built.
     
  8. W7DEX

    W7DEX Ham Member QRZ Page

    Looks like a great design! Do you have a parts list for this design? I'm curious to see what type of relays you're using for this, solid state or electromechanical? Also, what type of diodes?
     

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