[TenTec] Value of RX Only Antennas

Kim Elmore cw_de_n5op at sbcglobal.net
Sun Sep 22 14:30:52 EDT 2013

I think the thing to remember about rx antennas like small loops is 
that, while some of the noise may have a preferred polarization and 
small loops may provide some polarization isolation, they mostly reduce 
noise because of their directional characteristics. While they have very 
low efficiency, that's not a problem for rx purposes. If we assume that 
the noise comes equally form all directions because a loop has such 
sharp nulls means that the noise in those nulls is heavily attenuated 
while the desired signal isn't. If there is a particular noise source 
(that's not in the direction of your desired signal) adjusting the loop 
to null that source may be even more beneficial.

Kim N5OP

On 9/22/2013 12:46 PM, Spencer wrote:
> I almost gave up SWL in metropolitan areas outside
> the USA. I made a small multi-turn loop using FLAT
> 4 conductor telephone wire and resonated with a BCB capacitor. A small 
> ferrite bead on one of the wires to couple to the radio. Very narrow 
> band but almost noise free.
> Spencer W1GAK
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