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Homebrew ATU

Discussion in 'Homebrew and Kit Projects' started by M6YDF, Jul 13, 2018.

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  1. M6YDF

    M6YDF XML Subscriber QRZ Page

    Hi all.
    Just prototyping an ATU. Very simple design using a variable cap and a length of coiled wire. It seems to work well so far. Just wondering if the final would be best housed in a metal case (to help combat RF)?

    Thanks in advance!

    Simon M6YDF
     
  2. G3YRO

    G3YRO Ham Member QRZ Page

    Your aerial radiates RF . . . so I wouldn't worry about putting it in a metal case !

    I used to use an end-fed half wave, with the end of the wire going to the ATU which I built in a wooden box.

    Roger G3YRO
     
  3. AA7QQ

    AA7QQ Ham Member QRZ Page

    I would suggest a metal enclosure. It helps contain the RF & lethal voltages, that are possible.

    Ed
     
    KU3X likes this.
  4. K6BSU

    K6BSU Ham Member QRZ Page

    That "simple" ATU might work in your application.

    A slightly more sophisticated ATU will work in nearly all cases. Sooner or later, you will wish for an ATU which is more versatile.
     
  5. G4COE

    G4COE Ham Member QRZ Page

    Might be an idea telling us what antennas you are matching, which ATU config. and the power level.

    Dave
     
  6. M6YDF

    M6YDF XML Subscriber QRZ Page

    It's for my G5RV jr. 10 watts
     
  7. G3YRO

    G3YRO Ham Member QRZ Page

    Well you would be MUCH better converting your G5RV into a proper Doublet . . .

    Run the balanced feeder all the way to the ATU (unlike on a G5RV, the length doesn't matter) . . . make a Balanced ATU, then you can tune the Doublet on ANY frequency, which then is a proper match to your 50 ohm rig.

    Roger G3YRO
     
    AG5CK likes this.
  8. M6YDF

    M6YDF XML Subscriber QRZ Page

    Food for thought! Thanks Roger!
     
  9. K8JD

    K8JD Ham Member QRZ Page

    Just a var cap and a coil sounds like a single band device. Is that your intention ?
     

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