QST Article – “Live Trees Affect Antenna Performance” – implications for #POTA #SOTA

In February 2018’s QST was a very interesting and scholarly article, the cover story actually, on the effects of live trees on the performance of both vertical and horizontal antennas.  Things to ponder:

  1. Living wood (trees, as opposed to dry dead wood such as boards) absorbs EMF from vertically polarized antennas.
  2. Living wood resembles human tissue in terms of dielectric properties, so wearing your HT on your belt will greatly reduce your effective antenna power.  Presumably, unless you’re a real fathead like me, talking into HT held at your face should not be too bad.
  3. A single vertical tree has next to no effect on horizontal antennas, such as dipoles.
  4. A forest, containing lots of vertical trees, is even worse than a single tree like in your backyard, so for us backpackers and hikers, we need to find a clearing when trying to use our HT’s in the woods.
  5. Worse, a forest will affect both vertical and horizontal antennas so when we’re operating in the field, for POTA or SOTA for example, we should look for a Goldilocks spot with enough trees to launch the, say, dipole, but not too many.  Better in Winter after leaves fall, though.

This is Wayne,  k4wk, http://www.hamdom.com.  Thanks for listening; you’re in the log.

Wayne Robertson, K4WK, is a regular contributor to AmateurRadio.com and writes from Georgia, USA.

2 Responses to “QST Article – “Live Trees Affect Antenna Performance” – implications for #POTA #SOTA”

  • David Harden, KJ4CMY:

    I always knew that forests affect VHF/UHF propagation, but this an interesting addition to this knowledge. Thanks!

  • Lenny W2BVH:

    I get on 1296 MHz every Monday night (cw / ssb) and I’m shooting through the trees in most directions. Summer q’s are usually down 1 1/2 or more s-units over winter, presumably because of the leaves.

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