Date: Mon, 10 Jan 2005 00:37:36 +0000
From: "J. Allen" <vy1ja@northwestel.net>
To: rsgb_lf_group@blacksheep.org
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Subject: LF: Antenna plans de  J.
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Alex, Jim, Markus, and LF,

The reason for setting my calculations in front of all, is that I am new to 
LF and want the station to have early  success, rather than being a set of 
mistakes and recoveries.  You might be surprised, but although I am a 4th 
dan black belt and head of TaeKwon-Do Yukon, I am not a fighter, and have a 
tendency to give up on things which I have made a solid attempt at and find 
repeated failures.

The reason for using the complicated antenna structure as I describe it is 
that it is already standing... It is a large HF/MF V-beam with ~120 meter 
legs up ~20 meters, with ~55 degree included angle.   The antenna is fed 
with 75 Ohm hard line which was in with a number of damaged tower sections 
which I earned by cleaning up a commercial broadcasting station construction 
site.  The towers had been taken down by persons unknown who cut the guy 
lines and let the towers fall!  I use this antenna on 160-2 meters and it 
functions quite well with an antenna tuner.  It is the receive antenna which 
I am now using on LF and although it is a sort of "short dipole"on LF, it 
works very well.

The area of the antenna for several KM in all directions is poor sandy soil.

I have on site approximately 20 km of ~#10 copper-clad high-tensile steel 
wire, which was used for overhead telephone wires for many years.  This can 
be buried for radials or more wires run up high to increase top capacitance. 
How big does the elevated counterpoise need to be at LF to be effective? 
With the wire I have available, I could make a fairly large one in terms of 
feet, but it would still be small in terms of wavelength.

It may be easier to put a loading inductor out at the tower end of each 
insulator, and add LF to the antenna use, than to build a new antenna 
system.

As to the typo.. It is not critical now that I know about it and can make 
allowance for it... When the loading coils are in and measurements can be 
take of the LF antenna as a system, I will again send calculations to the LF 
reflector to make sure that I am not running more power than I should be.  I 
prefer to have someone look at my work.  These are my limitations:

Technical Operation Data:
-A transmitter will be used between the frequencies of 135.7 and 137.8kHz, 
in the 2200 metre band.

-Emissions outside of this frequency range will be suppressed by a minimum 
of 30db from the fundamental signal.

-Bandwidth of the transmitted signal will be limited to 100Hz or less.

-Radiated power will not exceed 1 watt ERP.

-The transmitter will be operated with care not to interfere with authorized 
users. Authorization for experimental transmissions will be on a secondary 
user basis. I am aware of Canadian military operations in this frequency 
range and will avoid transmitting on their frequencies. Any requests from 
primary users to cease transmission or to change frequency will be 
immediately complied with.


I did not think to set 1W ERP relative to anything... I do not know what 
Industry Canada normally measures it to, and will need advice from 
experienced Canadian LF ops like Steve or Scott on the normal comparison for 
ERP.

Alex,  Thank you for your continuing help.  I am retired and live on a 
fixed, small income.  Litz (sp?) wire in not being considered.  I have 
friends at the local power company who are watching for a "pole pig" or 
other transformer with a burned primary winding and good secondary, which I 
can acquire at the value of the scrap copper within it.  I plan to 
disassemble it for the flat secondary copper strap winding, which is usually 
well insulated with a material that looks like varnish.  I have been given 
three pieces of 13 inch X 36 inch long PVC pipe, which I was going to use 
for loading coil forms (formers), but have been told that they are lossy and 
I should use something else.  At this point I am still planning to 
disassemble the transformer, but I do not know whether to use the PVC and 
accept the loss from it or to use another type of coil form.

I have about 20 pieces of 5/16 inch X 60 inch fiberglass rods which I can 
use to make a form if needed.

I can move the V wire insulators out from the tower by a couple meters if it 
will help.

I have found this LF group to be friendly and supportive, and believe that 
my chances of success are very likely to be a reflection of your direction.

I appreciate the humor of the group as well.

J.