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tree polarization (was Re: Antenna Selection)



Richard:
>>>Trees absorb *vertical* polarisation better than any other.
Franklin:
>> I am really surprised by that statement.
>> Can you provide a reference to the technical literature\
Richard:
>No. Saw it in RSGB's "Radio Communication" several years ago. Might have
>been in the same issue that talked about using trees as vertical radiators
>for hf 

Franklin:
I can believe it for HF.  At HF freqs, you need long pieces of tree to be
resonant.  For most kinds of tree, that means the trunk, and trunks are
indeed mostly vertical.  At higher frequencies, smaller branches, or even
leaves or needles are more likely to be the parts that matter, and they
tend (for most kinds of trees) to have a more random orientation.
Therefore, I'd be very surprised if signal attenuation due to trees was
very polarization specific at VHF or UHF or higher.  



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