Trees and HF RF Interactions

It’s well established that trees can attenuate RF signals, particularly at VHF and UHF, and particularly in summertime when leaves are added to the equation. But there hasn’t been much attention paid to the impact of trees on HF communication. W3DIY and G3WRT have concluded that close-in trees not only introduce signal loss but also change polarization and radiation patterns.

HENRY L. “RICK” CIOTTI, IAN J. DILWORTH

In 1976, G3WRT wrote a tongue-in-cheek letter in Wireless World (UK), commenting on the influence of a single tree on HF radiation, after reading that trees were being used by the military as makeshift HF antennas in the tropical jungles of the world by exciting the sap structure. My current (2022) interest was spurred by a contact with someone who lives in a densely wooded deciduous tree area in the U.S., W3DIY. The trees in question are shown in Photo A (summer) and Photo B (winter). His experience has been particularly disappointing for HF DX in his dense woodland location. Measuring and then modeling the influence of trees on HF propagation is the subject presented here using his wood dimensions and spacings as an example. An excellent article in QST1…

You're reading a preview of

CQ Amateur Radio (Digital) - 1 Issue, February 2023

DiscountMags is a licensed distributor (not a publisher) of the above content and Publication through Zinio LLC. Accordingly, we have no editorial control over the Publications. Any opinions, advice, statements, services, offers or other information or content expressed or made available by third parties, including those made in Publications offered on our website, are those of the respective author(s) or publisher(s) and not of DiscountMags. DiscountMags does not guarantee the accuracy, completeness, truthfulness, or usefulness of all or any portion of any publication or any services or offers made by third parties, nor will we be liable for any loss or damage caused by your reliance on information contained in any Publication, or your use of services offered, or your acceptance of any offers made through the Service or the Publications. For content removal requests, please contact Zinio.