Prototype Build: Backpackable Foldable Yagi antenna

This is only the proof-of-concept prototype.

I have been cooking a design for a backpackable 4-element Yagi antenna for some time now.

The basic idea is to make a telescopic boom out of two PVC pipes and have removable elements that store inside it.

It took me some time to figure the method of attaching the aluminum welding rod elements (used Kosh electrical connectors) and how to integrate the feed point inside the boom. This will be the next build step.web-0593-640

Feedpoint detail

I went through several Yagi designs and calculations but I finally found a workaround to impedance matching. A recipe/design calculated to be a 50-ohm one from the start.

It is the 100 grams 4 elements VHF Yagi-Uda by IZ2UUF.

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Temporarily assembled on a target stand pole.

For the purpose of testing and hoisting the antenna above ground, I screwed another piece of wood on a 90 degree angle, to balance the antenna vertically. Hoists were 3 pieces of cord with a tautline hitch 😉  adjusting their length for balance.

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I cut the elements to the final length right on the spot by consulting the SWR Meter. I started with 1.31 at 145 MHz and by removing some length I got 1.18 @ 145 MHz, 1.47 @ 142 MHz and 1.56 @ 149MHz. A fellow ham 50 miles away gave me a 5-9 RST.

It was a nice day, with coffee, sunshine and a non-HAM friend to help me. Who was flabbergasted by the process and what a few humble materials can do.

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2 thoughts on “Prototype Build: Backpackable Foldable Yagi antenna

  1. Hello SV2???. Thank you for writing. Nice DIY Yagi-Uda, built with stuff everyone can really find everywhere! I’m really happy you have been able to reuse my 50-ohm design!

    VY 73 de Davide IZ2UUF

    Like

    1. Thank you David….It has been my pleasure. Your design helped me look to other ready-to-build 50ohms designs.
      I wish you good success to your HAMventures.
      Hope you don’t mind, but I edited out of your post the last 3 letters of my callsign, for OpSec reasons.

      Like

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