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more about QRP / Backpack portable Random Wires

Discussion in 'QRP Corner' started by KK4NSF, Dec 14, 2015.

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  1. KK4NSF

    KK4NSF Ham Member QRZ Page

    The tests discussed in this post were done five years ago. Since that Time I've done a lot of other tests, designs and so forth..... but I still use the original results for my back-pack portable QRP set-up, and have had excellent results with it.

    I'm sure further testing using Field Strength Meters, and different test parameters would indeed produce additional information that would be helpful to the community. Anyone with an inclination to take up the project and build upon these results is welcome to do so.

    Dave
    KK4NSF
     
  2. AJ6KZ

    AJ6KZ XML Subscriber QRZ Page

    Just another anecdote about backpackable antennas. I recently made my own end-fed 40m half wave. It is made of stealth wire and connected at one end to a 49:1 balun that I wound myself. I just set it up today in the back yard in a very much less than optimal arrangement; one end of the wire was hung from the top of a 10 meter fiberglass mast and the wire swooped down in a catenary curve to be tied off to a branch about six feet up a small tree. Here are the results I got.

    40m (7.0 to 7.12): 1.5:1 or better (best was 1.33:1 @ 7.05).
    30m: forget it.
    20m (14.0 to 14.12): 1.25:1 or better (best was 1.19:1 @ 14.05).
    17m: 1.5:1 pretty much flat across the band.
    15m: 1.5:1 or better (best was 1.19:1 @ 21.225).
    12m: 5:1 flat across the band.
    10m: 2.5:1 at the lower end dipping to 1.1:1 at 29.343 and then climbing back up a bit towards the high end of the band.

    I felt fine about using this antenna without a tuner on 40, 20, 17, and 15. All in all I was happy with the results. Obviously my testing is skewed towards CW, but if your interest is SSB you would tune to your area of the band.
     

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