On Sat,3/19/2016 4:17 PM, Barry N1EU wrote:
I've had excellent results with a variety of properly fed random wires when
operating QRP portable.
Yes. But properly fed is the key. :) The best way to feed a random wire
in most portable operations, especially backpacking, is a wire somehow
placed sort of vertical, even if it's sloping, terminating at the output
of the rig, and with some sort of counterpoise going sort of in the
opposite direction from the random wire.
That random wire will work best if both it and the counterpoise aren't
too different from a quarter wave (3/16 to 5/16 is great) or 3/4 wave
(9/16 to 11/16 is great). These lengths do three things -- they make the
antenna easier to load with the tuners in most rigs, they minimize the
number of funny lobes in the pattern, and they reduce losses in the
counterpoise. The random wire will also work better if the counterpoise
is at least 1/20 of a wavelength above ground. Laying on top of low
brush is good, because it reduces ground losses.
An important way to think about this is to remember that the
counterpoise is half of the antenna.
73, Jim K9YC
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