80M Inverted L for 160?

Discussion in 'Antennas, Feedlines, Towers & Rotors' started by WY0Q, Nov 2, 2019.

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  1. WY0Q

    WY0Q Ham Member QRZ Page

    I know the 80m Inverted L is too short for 160m. But I have heard that some folks get away with it with the tuner. Anyone have any luck with that or heard of that?
  2. K7TRF

    K7TRF Premium Subscriber QRZ Page

    You might get away with it if you have a very good tuner like an ATR-30. But the easier way is to add a large loading coil in series with the antenna feed point that loads the antenna at least close to resonance on 160 meters and then use a shack tuner to clean up the match. You can build the loading coil with a clip lead tap so you jump around the coil when you want to operate on 80 meters or build in a remote relay so you can select 80m or 160m operation from the shack.
    AK5B, K0UO and KU3X like this.
  3. WA7ARK

    WA7ARK Ham Member QRZ Page

    You will also have to add some longer radials to whatever you have now.

    What are the dimensions of the existing antenna?

    Are you willing to modify them?

    How much room do you have?
    Last edited: Nov 2, 2019
    K0UO likes this.
  4. N8AFT

    N8AFT Ham Member QRZ Page

    Try it and see.
  5. WA7F

    WA7F Premium Subscriber QRZ Page

    I had good luck on 160 and with an Icom AH-4 and a 130’ non-resonant Inv-L. That’s a great little tuner if you are running barefoot.
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  6. KU3X

    KU3X Ham Member QRZ Page

    The above is the correct way to use your antenna on 160 meters.

    By just using an ATU, you are actually putting way too much voltage on your ATU. MFJ sells coils if you look in their catalog. They are not that expensive. A relay is great, but if the antenna is easy to get to, moving a tap by hand is not a big deal.
    On my full size Delta Loop for 80 meters, I have a multi tapped coil on the horizontal wire so I can change from CW to SSB. It only takes 2 minutes to make the change.

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  7. WA7F

    WA7F Premium Subscriber QRZ Page

    There is usually more than one correct way. Remote tuners work great when end feeding a non-resonant wire. A resonant 80m Inv-L would need a little extra wire to avoid an unacceptable voltage feed. So about 130’ of insulated wire with a .96 vf or 135’ of bare wire. This also open up the Inv-L to multiband operation on 160-10m. If running QRO I’d probably go with your recommendation but, I do have a 1kW remote ATU that I’d like to try on an Inv-L. Either way there will be some losses but, they are both viable options.
  8. WY0Q

    WY0Q Ham Member QRZ Page

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  9. WY0Q

    WY0Q Ham Member QRZ Page

    160m problem solved. The radials in the ground were from my previous 160m Inv L antenna. About half are 123-130 feet. That is what I have been using for the 80m inv L. I installed another inverted L 125 feet and kept it away from the 80m antenna by at least three feet at the feed point. All I did was connect the 160m ant to the existing 80m feed line, like a vertical Fan dipole. It works great and does not affect the 80m Inv L. Seems to be effective. Made a phone contact to Idaho the other night. Thanks for all the ideas.
    AK5B and K7TRF like this.

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