[DX] Puuston vaikutus antenneihin

["T&M Ritola" <ritola@xxxxxxxxxx>]

Alla pari kommenttia NRC-listalta koskien puiden vaikutuksesta MW-antenneihin. Onko asiantuntijoilla kokemuksia, onko aukealle vedetty Beverage selkeästi parempi kuin tiheään metsään vedetty? Itsestä tuntuu, että tiheässä koivikossa sijaitseva K9AY:ni toimii nyt himpun verran paremmin, kun lehdet ovat pudonneet puista ...

73, MR

Colder weather and a huge wind storm the past couple days have ripped much 
of the leaves of the trees on my property. Last May when I moved my KAZ 
antenna from in front of my house to the west edge of my property to get it 
out of the way and away from as much power line noise as possible, I 
noticed the huge canopy of trees and leaves around it and hovering high in 
the sky behind it. This larger terminated delta loop just couldn't be made 
to null the back end as deeply as my former but still was very useful and 
with more signal pickup I never felt the need to turn the R8A"s preamp on.

Tonite, I noted 1050 seemed totally clear of semi local WLIP, Kenosha, 
who's 250 watts still is problem at night. Normally on 1050 I can hear 
things under or thru it, but tonite, I wrote in my log that WLIP was off 
the air. A while later, I switched antennas and there was WLIP blasting 
away far over the din of other stations.  I switched over to 620 and rather 
than having WTMJ atop and hearing things fade up underneath. WTMJ was at 
best equal to the QRM and normally clearly underneath.

Previously, I was getting about 22 dB of back null and I presume that the 
leaves on the thick woods right behind (South) and to the west of this 
sensitive antenna,must be getting enough signal to smear the deeper (my 
guess 30ish dB nulls) that I'm now getting.

I know leaves affect UHF and even VHF to some extent...but AM BCB ?!!?

Live and learn...73's KAZ

The trees, brambles, etc do affect antennas at MW. I especially notice
it on my NNW Beverage. It gets lost in the underbrash in the Summer/Fall
and when the leaves blow off a lot in the Winter the directivity and
gain of the antenna does improve. 

73s,

Patrick Martin
Seaside  OR
KAVT Reception Manager


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