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Author Topic: Interference from trees  (Read 12236 times)
N4WVE
Member

Posts: 33




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« on: June 21, 2013, 04:54:33 PM »

This may seem like a stupid question, but my PAR End fedz SWL antenna is located in a large oak tree. Will the foliage interfere with my reception? Huh
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Greg N4WVE
K0OD
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Posts: 2578




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« Reply #1 on: June 21, 2013, 09:09:57 PM »

Are you asking about rf interference, or signal reduction? I presume the latter.

Almost definitely not. Even if there's some loss, that wouldn't affect the signal to noise ratio. It would be like turning down the gain a few dB. Now, If you were to transmit with that antenna the trees might decrease your signal slightly and affect the SWR.

There are many variables: frequency used. species of trees, water content of leaves. density of foliage, height of antenna in relation to trees. The subject has received some scientific research that has been discussed on eham over the years.

I've used 50'+ oaks to support dipoles that work great on receive and transmit. Main problem is that tree sway will snap support lines within a few years.
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WA2ONH
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Posts: 260




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« Reply #2 on: June 22, 2013, 04:49:45 PM »

Here's a short article concerning Trees and HF operation by

Carl Luetzelschwab K9LA
Propagation - NCJ March/April 2006
Low Band Antennas and Trees

LINK: http://k9la.us/Low_Band_Antennas_and_Trees.pdf

A small PDF File approx 31kb in size.  Good Luck!
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73 de WA2ONH   ...Charlie
----------------------------------------------------------------------------
"No time is ever wasted that is spent LEARNING something!"
MISTAKES are proof that you are TRYING
G4FUT
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Posts: 88




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« Reply #3 on: July 02, 2013, 02:57:20 PM »

While in the UK Military we did some experiments using trees as antennae, by wrapping a long copper coil around the trunk. Just think if it caught on... we could have awards for say.  "Worked all Oaks"  Grin
Seriously, it was mainly tried in the jungle, and we did have some success.
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