[TenTec] re Trees

Dave, K2DP k2dp at charter.net
Sat Feb 4 10:00:42 EST 2006


I can assure you that running a dipole through a tree can cause RF to arc to 
the branches and burn/ignite a branch on the tree. It depends upon how you 
are feeding the antenna (coax vs open wire feeders) and where the current 
and voltage nodes appear throughout the length of the antenna. With QRO and 
shortened antennas fed with ladder line and high power, you can create 
significant current and voltage nodes where the element wire runs adjacent 
to tree branches. This occurs even with insulated wire. This morning, I am 
about to add some ADDITIONAL insulation to my modified Alpha Delta 100 foot 
long 40/80/160 mtr inverted V which I feed with Ladder line, using vinyl 
tubing bought in your local plumbing department. Hopefully, that will 
provide enough insulation for the portion of the element wire that runs 
through the tree in my front yard, lest I too have a "burning bush" at my 

By the way, whatever little attenuation the tree imparts to my signal, has 
not limited me from working the world on 75/80 mtrs this winter, so enough 
signal is definitely getting out from St. Louis to Europe, Africa and the 

Dave, K2DP
----- Original Message ----- 
From: "Rob Atkinson, K5UJ" <k5uj at hotmail.com>
To: <tentec at contesting.com>
Sent: Saturday, February 04, 2006 7:51 AM
Subject: [TenTec] re Trees

> The topic of trees has come up elsewhere (towertalk and a broadcast
> reflector i read) and i can say from reading them that the consensus is 
> that
> trees attenuate RF if they are in the near field.   this is why mw and sw
> broadcasters clear trees off their sites but, it isn't always such a big
> problem that you should abandon the idea of putting your vertical dipole
> amongst them.   I would be more concerned about pine tree contact with the
> high v. end of ur dipole and burning.   Have not experienced this myself
> (and being a chicken i hired a guy to trim a pine tree away from part of 
> my
> loop) and nothing may happen in your case, but if i were you and i ran 
> QRO,
> i'd rest easier if I could position the wire so that it's a few feet from
> any branches and needles, or if that isn't possible, trim anything making
> contact back a few feet.   Some guys say they get around this by using
> insulated wire, but I have also read that the insulation can rub off
> eventually.
> rob / k5uj
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