[TenTec] Portable QRP/SOTA

Jim Brown k9yc at audiosystemsgroup.com
Sat Mar 19 20:52:41 EDT 2016


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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