Message-ID: <000a01bed5f3$b06179e0$95eb869f@beachwood.tinet.ie>
From: "Finbar O'Connor" <beachwood@tinet.ie>
To: rsgb_lf_group@blacksheep.org
Subject: LF: Re: Ant effects
Date: Fri, 23 Jul 1999 01:40:47 +0100
MIME-Version: 1.0
Content-Type: text/plain; charset=iso-8859-1; format=flowed
Content-Transfer-Encoding: 8bit
Precedence: bulk
Reply-To: rsgb_lf_group@blacksheep.org
Sender: <majordom@post.thorcom.com>

Hi Doc,
           Found your comments regarding effects on Medium wave broadcast
antenna systems very interesting indeed, and as you say, LF must be effected
even more by surrounding objects, considering how  narrow tuned they are,
with our tiny antenna's. If I keep my present system in place until Winter
time, I will observe whether there is a gradual rise in Antenna current,
back to what it was, last Winter.
If we can get rid of Loran, on both sides of the Atlantic, perhaps we will
one day have an  LF/LF qso, however a friend of mine in Canada tells me that
the Loran signal really makes a mess of reception on    136 khz, pity
really.
Best regards
Finbar    EI0CF
-----Original Message-----
From: Doc Gruis <donnatom@netins.net>
To: rsgb_lf_group@blacksheep.org <rsgb_lf_group@blacksheep.org>
Date: 22 July 1999 02:56
Subject: LF: De-tuned antenna


>I really don't know if there is the practice in Europe of
>directional AM broadcast stations, i.e., 540 to 1600 (or 1700) KHz., but
>it sure is practiced here in the U.S.
>
>     The mention was made of the foliage growth close to the feed line,
>etc.  Here are a couple of many instances of natures messing up an
>antenna system.  Well, maybe three...)
>
>     1.  One station I worked at was on 1390 KHz. and had a four tower
>array and the tower field was surrounded by corn fields and even though
>they were over a hundred feet away at the closest point, the radiation
>pattern of the station was altered and so was the impedance's, tuning,
>phase, etc., of the towers.
>
>     2.  I worked at another 4 tower station on 1360 and for no apparent
>reason the whole array would go in and out of tune and specifications.
>Then one evening, I spotted a field mouse in the tuning house and found
>nests built inside the lighting isolation transformers or coils,
>whichever they happened to have.  The little mice must have thought it
>very warm due to R-F heating.
>
>     3.  And it seems like last winter someone on this list was talking
>about ice formation and that is enough said.
>
>     SO if the tuning is that sensitive at a frequency about ten times
>your 136 KHz. band, it must be devastating at the long waves!
>
>     I certainly enjoy the postings to this list.  Thank you very much!
>AND your home pages are very good indeed.
>
>     I have a 1 watt beacon operating on 175 KHz. and will be putting up
>a new antenna this autumn.  My efforts must be modest since our lot is a
>rather conventional 50 X 150'.
>
>73!
>
>Doc, K0HTF and long wave "D"
>
>