[CQ-Contest] to pre-amp or not to pre-amp

Jim Brown k9yc at audiosystemsgroup.com
Sun Jan 17 01:50:31 EST 2016

On Sat,1/16/2016 10:30 AM, Franki ON5ZO wrote:
> Question 1 is: would I benefit from a pre-amp right at the feedpoint 
> of such a flag or single K9AY loop antenna? Coax to the shack is about 
> 50-60m max.

This fundamental rule works for ANY antenna. Connect it to your radio. 
If the noise level from the antenna is at least 10 dB higher than the 
noise level with no antenna and a 50 ohm resistor at the antenna input, 
you don't need a preamp. Do this test under the quietest actual 
conditions -- if on 160, between an hour before sunset and an hour after 
sunset, on a day when static is low.

> Question 2 is: The copper wire 'wannabee beverage' runs 10-15 cm above 
> the conductive wire mesh fencing (1m to 1.20m high). Would it be 
> better to just put it on the ground as a BOG? What about a pre-amp there? 

It's generally accepted that Beverages do NOT perform well in proximity 
to other parallel conductors (like your fence).  Beverages work because 
of their interaction with poorly conducting earth, and other parallel 
conductors defeat that.

73, Jim K9YC

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