Re: [amsat-bb] trees

["Edward R. Cole" <al7eb@xxxxxxxxxxxxx>]

At 09:53 AM 7/13/2002 -0700, Bob V Johnson wrote:
>Hello
>Just how attenuating are fir trees at 2.4Ghz?  I was trying to work  into
>Europe and could not even hear the MB.  Would a bigger dish help?  I'm
>fairly new on AO-40 and I haven't had more fun since I lit up my first
>vacuume tube!
>73...Bob...W7LRD
>Seattle

Bob,

Conifers and fully leafed decidous trees are "death" to 2.4 GHz
signals...bigger dish?  Maybe 30 to 50 foot (joking)!  But realistically,
you need to get above or around those trees...a big chainsaw will help,
though*!  Other than that you are stuck with tree blockage.

I have a single line of 50-foot Birch trees along my street (to my
southwest) that screen the satellite...I can copy the beacon but the trees
knock down other signals so that working stations is near impossible
(better in the winter when leaves are gone).  BTW trees not only attenuate
the signal severely, but are also a source of thermal microwave noise
(ruining your receive noise foor).  I can see an s-unit of noise floor rise
when I lower my dish below tree-top level!

sorry,

Ed, AL7EB
*Note:  Not kidding here:  I dropped over 12-18 trees on my property
boundary to improve low elevation look angles.  Easy to get away with in
Alaska as heating with firewood is still prevalent!  In a state with
highest per-capita gun ownership, what one does on his own property is
respected!  {SW treeline is on power company easement, though}

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