[Towertalk] attenuation of fir trees at 50 mhz and 144

[John D. Farr]

Dan:

The NABS document "Transmission Loss Predictions for Tropospheric
Communication Circuits" by P. L. Rice, A. G. Longley, K. A. Norton and A. P.
Barsis gives the equation

    Aw = d(0.244 log f- 0.442) decibels , (f > 100 MHz)

where Aw is the absorption in decibels through d meters of trees in full
leaf at a frequency of f megahertz.

They state that this is an empirical relationship. They cite J. A. Saxton
and J. A. Lane "VHF and UHF Reception-Effects of Trees and other Obstacles"
Wireless World, May 1955.

Hope this helps
John KC4ZXX


----- Original Message -----
From: "DanB" <longterm@chatusa.com>
To: "tower" <towertalk@contesting.com>
Sent: Saturday, May 18, 2002 8:21 AM
Subject: [Towertalk] attenuation of fir trees at 50 mhz and 144


> Looking for a study on attenuation of fir trees at 50 MHZ and 144.
>
> Dan NN7J
>
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