From: "Des Kostryca" <des@kostryca.freeserve.co.uk>
To: "RSGB LF_Group" <rsgb_lf_group@blacksheep.org>
Subject: LF: Advice on Antenna.
Date: Tue, 14 Sep 1999 01:07:52 -0700
Message-ID: <000e01befe88$3e764be0$572e883e@default>
MIME-Version: 1.0
Content-Type: text/plain; charset=iso-8859-1; format=flowed
Content-Transfer-Encoding: 8bit
Importance: Normal
Precedence: bulk
Reply-To: rsgb_lf_group@blacksheep.org
Sender: <majordom@post.thorcom.com>

Hi Everyone,

   Following a request to this reflector for advice on setting up an L.F.
station (last winter) the help I received has enabled me to gradually build
up a station which will be ready for testing within a few weeks. I promise I
will do my best not to be one of those "deaf" stations and intend to ensure
optimum receiver sensitivity. My special thanks to Steve Rawlings (GW4ALG)
for his transverter circuit notes, this has now been built and works very
well. I have been listening to activity on the band using the "strapped"
feeder to a short doublet antenna to get a "feel" for the band and operating
practices.

The final part of my L.F. project requiring construction is the antenna.
Though I had decided on a "T" antenna I now find that due to a lack of
viable supports for the top loading wires I may have to "re-think" my
antenna. The vertical part /around 10 mtrs) is ok but I have a number of
options for "top loading" and I should like to ask the opinion of yourselves
as to the best option to choose from the following list:

1) 10 mtr vertical only i.e. No top loading.
2) 10 mtr vertical with top loading "T" wires (7 mtrs each side) sloping
downwards.
3) 10 mtr vertical with about 7 mts of horizontal wire at the top to form a
sort of inverted "L" type antenna.
4) 10 mtr vertical with 3x7 mts of horizontal wire to give increased
capacity.

>From the texts I have read the theory would seem to suggest that a vertical
antenna offers the best chance of success and the use of some form of
capacity hat is desirable (top loading capacity) this reduces the amount of
loading inductance and hence the loss. Reducing the number of turns on the
loading coil can mean lower voltages and less risk of insulation break down.
For these reasons I should like to include some top capacitance if possible.

 Reading past postings on this reflector it seems to me that the classical
theory alone is not the full story and that successful practical "garden
sized" L.F. antennas can be made to work. For this reason I should like to
ask those of you on this reflector with experience with small garden sized
vertical antennas for your opinions and advice. Thanks in advance and I look
forward to working some of you on L.F. in the near future.

73's

Des.

Des Kostryca (M0AYF)  G.Q.R.P. no. 9788
I.A.R.U.  loc.  IO93OJ  W.A.B.  SK89
Member of the N.B.T.V.A.