Topband: tree losses

[ZR]

Jim, it seems to be a difficult subject for those who want to make a huge 
case out of taking measurements as if this was a scientific undertaking 
requiring a decade of reviews, papers, and the usual academia way of wasting 
time.

For the rest of us ancedotal evidence is often sufficient...if the tree or 
parts of it died coincidental with installing an antenna or increasing ERP 
then that is good enough IMO. Others can hire an arborist and a passle of 
investigators from the County Extension who just might take you to court 
along with a screaming horde of tree huggers demanding your scalp (-;

Foliage induced attenuation without obvious damage is another subject all 
together. That will vary by the tree, climate, phase of the moon and when 
the dog last peed on it. And like the perennial discussion on 
grounds....everyone has an opinion and different circumstances.

Carl
KM1H



----- Original Message ----- 
From: "jim rogers" <jdrog at bellsouth.net>
To: "ZR" <zr at jeremy.mv.com>
Cc: "Topband" <topband at contesting.com>; "Rudy Severns" <rseverns at gmail.com>
Sent: Monday, August 05, 2013 9:03 AM
Subject: Re: Topband: tree losses


> Carl et al,
>
> Interesting, my 80M full size (66') sloper comes within about 5 ft of a 
> dogwood tree and it is dying. The sloped is fed 8' AGL with 2 full size 
> elevated radials and about 500w and the dogwood is dying from that 
> height(8') to the top of the tree at about 15'. Unfortunately for me, my 
> XYL pointed this out to me - not good. The sloper has been in that 
> position for about 1 year, before that the tree was doing fine.
>
> Coincidence?
>
> Jim N4DU
>
>
> On 8/4/13 9:42 PM, ZR wrote:
>> I cant think of anyone claiming a tree is resonant on any particular 
>> frequency but that doesnt mean it cant be used as an antenna. Anyone 
>> disagreeing with that should discuss it with the military who have been 
>> loading trees for decades for emergency communications; in the 3-8MHz 
>> range if I remember and going back as far as the 50's. Read the old CQ 
>> and QST's.
>>
>> On another note I spent most of today outside doing tree trimming and 
>> other sweaty exercises. I noted that my best producing Bartlett pear tree 
>> was dead at the top and also a bit down on one side. Now it may be just 
>> coincidence but the 80M sloper passes about 5' from the farthest out 
>> branches and the end is exactly at the same height as the tree top.
>> This antenna is used at the vintage gear bench and also on the one for 
>> amp repairs where Ive been hitting it rather hard this year with AM with 
>> serious carrier power; the most recent being an Alpha 77SX.
>>
>> I also remember wilting the top of a sugar maple about 20 years ago with 
>> 1200W on 6M to a 6/6 yagi array. After I moved the antenna to another 
>> tower the tree recovered the following year.
>> Another coincidence?
>>
>> Carl
>> KM1H
>>
>>
>> ----- Original Message ----- From: "Rudy Severns" <rseverns at gmail.com>
>> To: "Topband" <topband at contesting.com>
>> Sent: Sunday, August 04, 2013 5:39 PM
>> Subject: Topband: tree losses
>>
>>
>>> Tom's correct, the issue is not "resonance" but rather what, if 
>>> anything,
>>> happens when you have a so-so conductor/insulator (a tree) in the 
>>> near-field and/or further out. Do the losses matter?
>>>
>>> Performing a definitive set of experiments would be a serious 
>>> undertaking. I've fiddled around a bit but not much more than the tree 
>>> conductivity work mentioned earlier.
>>>
>>> At this point I'm an agnostic: we really don't have good data. There are 
>>> a number of Vietnam era papers on trees as antennas and propagation 
>>> through jungle but most of that was at frequencies well above 160m.
>>>
>>> Here's a challenge for experimenters that'll keep you busy and out of 
>>> the
>>> bars.
>>>
>>> 73, Rudy N6LF
>>>
>>>
>>> _________________
>>> Topband Reflector
>>>
>>>
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>>
>> _________________
>> Topband Reflector
>>
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