Topband: Trees (not the N6TR kind)

[Richard Fry]

As for the affect of trees on EM waves, below are the results of some simple 
measurements I posted earlier on another board.
___________________

Recording the relative readings on the dBµ and S/N displays of a Tecsun 
PL-310 tuned to a directional station about 52 miles east of me on 790 kHz, 
radiating about 1 kW in my direction:

        Location                                     dBµ                S/N 
(dB)
   (Tecsun 4-1/2 ft AGL)
Area clear for 50 ft around                    32                       15
Pin oak tree, 3' diameter trunk,             42                       24
  east side against trunk
Ditto, but west side of trunk                  34                      14
Gnd Wire of 50' utility pole                    48                      24
   (Tecsun 9 ft AGL)
Gnd Wire of 50' utility pole                    50                      24

These locations were all within 100' of each other, in my back yard.

(later)

I just went back out to my pin oak tree, tuned in the 790 kHz station east 
of me, and found that the field improvement when the rx is held against the 
east side of the trunk is completely gone when the receiver is moved to the 
east about 15 feet.  So this is quite localized, and probably wouldn't have 
much of an affect on a DA unless an MP was poorly located.

R. Fry