Hi Jim,
One disadvantage of a big loop is the (dc) voltage it collects, the 600
ft delta at gb4fpr has a habit
of producing quite big arcs' if its not earthed ... and not just a small
one at that!!.
even on a fine sunny day ..it may be simply wind-age or perhaps ozone
from the sea,
may also account for the very high noise level as well ..?
Being surrounded by salt water seems to be a case of 'all that glitters
in not gold'
73 - G ..
Ps - Interesting topic .. may solve the 'problem'
--------------------------------------------------
From: "James Moritz" <[email protected]>
Sent: Friday, July 24, 2009 12:23 AM
To: <[email protected]>
Subject: Re: LF: Loop discussion
Dear Ha-Jo, LF Group,
The beauty of a large wire loop of several m^2 is that a high signal level
is produced, making tuning and matching non-critical, and so it is a very
simple and versatile antenna which works well over a wide frequency range.
My version of an outdoor wire loop tunable in the shack was the "Lazy
loop" - see http://www.wireless.org.uk/lazy.htm
When you are trying to make a much smaller loop with essentially the same
performance, design is more critical due to the lower signal power
available
from the loop, so the technical details need to be studied, and the
solution
has to be more closely defined. But the end result is still simple - a
single turn loop, a transformer, a preamp. In the case of the bandpass
loops, a few inductors and capacitors do impedance matching and define the
passband. It is worth going to this trouble, because a compact, portable,
easily rotated loop that does the same job as a much bigger antenna is a
useful thing to have.
Cheers, Jim Moritz
73 de M0BMU
----- Original Message -----
From: <[email protected]>
To: <[email protected]>
Sent: Thursday, July 23, 2009 9:20 PM
Subject: Re: LF: Loop discussion
Dear James and Alberto,
I must confess that my considerations were much simpler. I wanted to
find a solution for an outside wire (normal litz wire for electric home
wiring) loop for broadband reception and to transfer its received energy
into the shack via a cable. Especially at VLF to MF cable losses are
rather low. Furthermore I wanted to locate all electronic equipment in
the shack only, no remote controls or similars. My solution is simple
and is working according to my expectations.
73 Ha-Jo, DJ1ZB
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