[IRCA] Fwd: Topband: tree losses
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[IRCA] Fwd: Topband: tree losses



From a discussion on the Topband list concerning the effect of trees and foliage on a transmitted signal. Make of it what you will.

best wishes,

Nick


From: "Richard Fry" <rfry@xxxxxxxxx>
To: <topband@xxxxxxxxxxxxxx>
Date: Mon, 5 Aug 2013 06:05:13 -0500
X-Mailer: Microsoft Windows Mail 6.0.6002.18197

Rudy Severns wrote:
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?
________________

Here are several data points on this subject.

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

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 the effects are quite localized.

These locations were all within 100' of each other.
_________________
Topband Reflector



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