[NLRS] Is there published data on tree foliage ...

[Donn, WA2VOI]

'Morning, Chris.

No, the report doen't state "condition" of the foliage.  From contest, however, 
I assume it refers to "dry" foliage.  The report treats each source of loss 
seperately: i.e., atmospheric, water vapor, rain, scattering, etc.  (The report 
is aimed at mm wavelength propagation.  The foliage loss equation just happens 
to cover down to 200MHz.)

FWIW, I agree with you completely re: rain-covered foliage and TV signals.  My 
"look" at the Shoreview towers is blocked by a hill and I suffer badly from 
multi-path.  Dry conditions are... OK, but during and after rain, no so much.

73 Donn
WA2VOI/0

PS The FCC report is readily available on the Internet.  (Where I got it 
originally.)  Don't rememebr exactly, but 'FCC OET Bulletin 70' in a search 
engine should find it.
(dbb)


----- Original Message ----- 
From: "Chris Elmquist" <chrise at pobox.com>
To: "Donn, WA2VOI" <wa2voi at mninter.net>
Cc: <NLRS at mailman.qth.net>
Sent: Thursday, July 10, 2014 12:33 PM
Subject: Re: [NLRS] Is there published data on tree foliage ...


>
>
> On Wednesday (07/09/2014 at 11:03PM -0500), Donn, WA2VOI wrote:
>>
>> This may help.
>>
>> Foliage loss
>> L(dB)= 0.2 * f^0.3 *R^0.6
>> where: f = MHz
>> R= depth of foliage (in meters)
>> Valid for 200 - 95,000 MHz
>> Depth of foliage R < 400m
>>
>> From:
>> CCIR Rpt 236-2
>> FCC OET Bulletin 70, July 1997
>
> That's interesting.  Does it indicate whether that is dry or wet?
> or the worst case?
>
> Judging by attenuation of broadcast TV here, on say 600 MHz, wet trees
> are way worse than dry ones...
>
> Chris N0JCF
>
>> ----- Original Message ----- From: "Bill Smith via NLRS"
>> <nlrs at mailman.qth.net>
>> To: <NLRS at mailman.qth.net>
>> Sent: Thursday, July 10, 2014 2:51 AM
>> Subject: [NLRS] Is there published data on tree foliage ...
>>
>>
>> >
>> >
>> >... absorption at 432 mHz?
>> >
>> >Any reference would be appreciated.
>> >
>> >Thank you es 73.
>> >
>> >Bill, W0WOI
>> >______________________________________________________________
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>
> -- 
> Chris Elmquist
> ______________________________________________________________
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