Hi Roger if it is laid on the ground the currnet will couple to the lossy
ground increasing the aerial loos and reducing the already low efficiency
of
the loop. You might search for articles by Bill Ashlock who has done a lot
of systematic experiments with TX loops in the States. I dont recall
anyone
bar Dave Sargent using a loop in the UK.
Alan G3NYK
----- Original Message -----
From: "Roger Lapthorn" <[email protected]>
To: <[email protected]>
Sent: Friday, August 13, 2010 4:08 PM
Subject: LF: A question about loops for 136 and 500kHz TX
Having considered the antenna options for my small garden, I'm going to
erect a TX loop antenna rather than a Marconi vertical for 136kHz: the
earthing issues are removed and it is easier to build a capacitor
selection
box (to tune and match the loop) than wind a huge loading coil and match
it.
I've seen some of the webpages dealing with these and understand
basically
what is needed (large loop area, thick wire, capacitor match-box, dealing
with high RF currents, etc). I understand the loop will have
directionality
and nulls.
My question is this. *Is there any reason why the bottom of the loop
cannot
be laid along the ground rather than elevated a few metres?* Most designs
show the bottom elevated a bit, but if laid on the soil I could use thick
coax or multiple wires for part of the loop so reducing the loop
resistance.
Views appreciated, although it may be a case of "suck it and see".
73s
Roger G3XBM
--
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http://www.g3xbm.co.uk
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G3XBM GQRP 1678 ISWL G11088
