How to test for tuning capacitor watts

Discussion in 'General Technical Questions and Answers' started by CAMERART, Oct 13, 2019.

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  1. CAMERART

    CAMERART QRZ Member

    Hi M,
    No I simply forgot which way it works.
    C
     
  2. CAMERART

    CAMERART QRZ Member

    Hi K,
    I think it goes out of match in different location situations, I'll see what happens.
    C
     
  3. GM3ZMA

    GM3ZMA Ham Member QRZ Page

    I am a little bit late to this thread, but I have just found a snippet of information which may be relevant.

    While reading something about Q measurements by W7ZOI, I noticed that he made some comments about a polyvaricon capacitor which he tested as part of his investigations into the Q of various capacitors and inductors.

    The document by W7ZOI is here:
    http://w7zoi.net/twofaces.pdf

    The interesting part is on page 19 of the document where he says:

    With that in mind, it could be that the polyvaricon tuning capacitors from transistor radios are a very poor choice for use in a simple ATU, even one which is only ised for low power (<5Watts).


    As a side note, my thanks to VK2TIL in this thread:
    https://forums.qrz.com/index.php?threads/using-vna-to-measure-coil-inductance.681215/
    for bringing the Q measurements document to my notice.

    Jim GM3ZMA
     
  4. AA7QQ

    AA7QQ Ham Member QRZ Page

    Good going !!! Even if it is me, once in a while.

    Ed
     
    KD0CAC likes this.
  5. AA5MT

    AA5MT Ham Member QRZ Page

    Cushcraft used to make the Skywalker monoband antennas. They used a series capacitor with a thick dielectric. The plates were about a foot long. In effect, it looks much like RG-8 with a solid sleeve. I suspect the reason they were discontinued was that it could not take the power. At least over a long period. You can get a manual on the Cushcraft Help Desk.

    Tom
     
  6. CAMERART

    CAMERART QRZ Member

    Hi J,
    Thanks for the links.

    I have looked at all this for years, and it doesn't get remembered unless, I try it live, by experiment. I'll have a 'play' soon.

    I've added the little metal plate cap into the box, and I hope to test it.
    C
     
  7. CAMERART

    CAMERART QRZ Member

    Hi T,
    "A foot long"! I won't really fit in the 2inch box I have, but thanks.
    C
     

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