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Re: [DX] Puuston vaikutus antenneihin
Tervehdys kaikille,
itselläni on vain näitä peltolankoja joten en osaa verrata metsään
vedettyihin. Olen kuitenkin ollut tyytyväinen näihin maan pinnalla
vedettyihin beverageihin, samoin lw:n, häiriöttömyys ja
suuntaavuus on niiden paras etu verrattuna takakeiloihin.
Väittäisin, että tiheän metsän sisälle vedetyllä langalla ainakin
suuntakuvio on huonompi, koska langan suoruus ei ole samaa
luokkaa kuin aukella olevalla langalla - eihän suoruutta pysty
kunnolla edes tarkistamaan - lanka ei myöskään ole vaakasuora.
Muistelen jonkun ruotsalaisen joskus verranneen kahta
beverageaan toisiinsa ja maadoituksen lisäksi langan suoruus oli
eroja aiheuttava tekijä.
MKA
On 27 Oct 2001, at 11:26, T&M Ritola wrote:
> 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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