Re: [amsat-bb] Foliage Attenuation at 2400mhz?

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

Tony,

In an earlier e-mail discussing tree blockage I related that I have a
single line of birch trees lining the street and power line which blocks my
view of AO-40 in the southwest (up here the elevation angle is usually
around 10-20 degrees in that direction...I think the max elev due south is
sometthing like 35 degrees).  Last winter, without leaves, I noticed some
blocking effect but could copy signals thru the trees (the beacon was
fine).  Now in summer with full foliage it is considerably worse (only can
hear the beacon, mainly).

Now I wish I had told the tree cutters for the electric company to just
take out all the trees last fall.  They cut the tops out the ones right
under the lines but left tall ones to the outside.  I can't cut them
because they are too close to the lines; the only direction I could fall
them is across the highway!  Fortunately I have a good window from east to
south.

Ed, AL7EB

At 08:56 PM 7/28/2002 -0400, AA2AE wrote:
>Group
>
>I was wondering what to expect from AO-40's 2400mhz downlink when beaming
>through the tall trees in my back yard. Since AO-40's orbit is such that
>beaming due south through the trees ( I live in the northeast ) can't be
>helped, my reception will suffer to a certain degree during the year when
>the trees are full with leaves.
>
>Has anyone noted a difference when beaming through trees, with and without
>leaves? I'm sure moisture content in the leaf itself, and the leaf density
>the signal has to beam through plays any important part in how much
>attenuation takes place, but is there a general "rule of thumb" expressed in
>db for this band?
>
>Thanks
>
>Tony - AA2AE
>
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