[Elecraft] Electric fence QRM?

[Dale Boresz]

Deni wrote:

>Any tips on eliminating or reducing Electric fence QRM, apart from moving !
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>  
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Deni,

I don't know anything about electric fences, however I periodically have 
power line noise which can be quite strong - anywhere from S3 to S9 - 
and although the K2's NB does a wonderful job most of the time, the 
characterstics of this particular noise are such that the NB does 
nothing at all. The NB on the 746PRO is not the least bit effective either.

However, I can eliminate it completely by using the MFJ-1025/1026 Noise 
Cancelling device. I've had the 1025 for about 5 years now, and other 
than the K2 itself, it's the one piece of equipment in my shack that I 
would not want to be without.

A simplistic explanation of how the device works is:
It has two antenna inputs - one for your main receiving/transmitting 
antenna, and another for a 'noise' pickup antenna. The box gives you the 
ability to alter the phase and amplitude of the signal from the noise 
antenna with respect the the main receiving antenna, so by careful 
manipulation of phase and amplitude, the offending noise can be 
virtually cancelled, leaving everything else intact. I've successfully 
eliminated even S9 noise - BUT the key to success with this device is 
being able to obtain a 'noise' signal on the noise input with 
sufficiently strong amplitude, and ideally it should be as strong or 
stronger than the noise being picked up by your receiving antenna. If 
you are physically near the fence, and can place a noise pickup antenna 
nearby, you'll have the ideal situation.

The usual disclaimers - not associated w/ MFJ, no financial interest in 
the company, etc....., but as I said, I wouldn't be without it.

73, Dale / WA8SRA