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Re: [IRCA] Wellbrook Large Aperture Loop Antenna ALA100LN
Hi Mark,
I suspect you hit the nail on the head when you said
Being near the seashore probably means that the signals are "beefy"
enough most of the time.
Those of us who are more inland notice the limitations of the lower
signal antennas like untuned loops and the uni-directional loops such
as the Flag. DX can be pretty wispy on these antennas in such locations.
Even though my location is "coastal" by many DXers' standards, it's
still over 50 miles to the open Pacific from here, and I noticed the
difference immediately upon switching from unamplified Flags to using
the FLG-100. A lot of the improvement is due to overcoming the
local electrical noise that is conveyed to the antenna by the coaxial
feedline that many use, but sometimes it is just plain better
readability on an overseas signal due to more signal strength at the radio.
I suspect that the noise problem could be mitigated by careful use of
twisted pair feedline, perhaps multiple common mode chokes,
well-placed earth grounds etc., but most have neither the time nor
the expertise to investigate that black art, when a well-designed
amplifier out of the box will get one into the thick of the DX right away.
best wishes,
Nick
At 03:58 03-02-16, Mark wrote:
Flags, Deltas, and SuperLoops can indeed be changed to bidirectional
(figure-of-8) from cardioid by shorting out the termination resistor.
I do that here from time to time on N-S loop when it's more
important to null NYC (W) instead of Boston / Portland (N) when
DXing Latin America (S).
Depending on the size of the loop, you might want to go to a 1:1
transformer at the feedpoint for bidirectional instead of the usual
one in the 9:1 to 16:1 range used for the cardioid set-up.
10m high by 11m long loop here does not need any amplification
either in cardioid or figure-of-8 mode.
Being near the seashore probably means that the signals are "beefy"
enough most of the time.
Not sure why such a simple antenna needs to be purchased, especially
if you don't need to amplify. You just need some wire, supports,
easily-built RF transformer, and feedline to the shack. Maybe about
$40 worth of parts altogether.
Mark Connelly, WA1ION
South Yarmouth, MA
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