Ok JB
The loop is a equilateral triangle 'flat', running about 90 feet above the
sea level , each side is 200 feet , with the feed at the apex of the
south - east side, opposite is the 'base' running approx , north east
/south west. Total cable length just over 600 feet , 35 amp insulated mains
cable was used, as we had a roll and it keeps the salt spray off the wire
The voltage build up seems to be more of a problem with the loop, not sue
as to the final pd , but it gives a good flash and already has sent one
chap across the room .and that was on a fine sunny day ... the wire to
the light house, 680 feet, is still in place .. amazingly ... doesn't seem
to have the same static build up problem .. still charges but no where
near as much
The main use of the loop to date has been tx/rx on the HF ham bands fed
from a balanced tuner and rx on 500, with one end grounded and the other
direct to the rx ... this produces quite a high level of noise, next is to
try a small tuner with loop coupling to float the array . We have not yet
transmitted on the loop at 500 but the rx tuner should handle the 50
watts so we can take a signal reading at G4WGT grabber. The marine tx is
looking for a very low Z feed so any Ae coupling tends to be step up ,
the long wire is tuned with a parallel tuner , sort of 160 mtr fashion.
We did initially try a conventional loaded vertical system, however as the
Fort is 1000's of tons of sandstone rock it was difficult to tune the
system with 'no' earth as such , the loop was installed to take its place,
then we found that the lighthouse was owned by the owner of the fort
...one of those 'oh that's handy moments'
http://uk500khz.googlegroups.com/web/gb4f.jpg
73 - G ..
--------------------------------------------------
From: "J. B. Weazle McCreath" <[email protected]>
Sent: Friday, July 24, 2009 2:12 AM
To: <[email protected]>
Subject: Re: LF: Loop discussion
Hi Graham,
Would you kindly pass along some details of the GB4FPR delta loop?
I've been using one here with a perimeter of 333 feet for several years
now for receiving purposes in the range 160 to 530 kHz. A binocular
core with a 1:2 turns ratio at one of the bottom corners provides the
step-up to the RG-6U coax to the receiver. I've no problems with
static charges or arcs (so far), but I have thought of putting some
high value resistors from the loop ends to ground.
73, J.B., VE3EAR - VE3WZL
Solar and wind powered
Lowfer " EAR" 188.830
EN93dr
http://www.hurontel.on.ca/~weazle
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