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I had a commercially made Common mode choke some years ago. I first placed it just outside the shack and there was little difference. Then I added a long piece of coax and set the choke way out in the yard and it did make some difference but the added coax may have done that, not sure. I eventually added one I made up at the feed point of my 5 band quad and that solved all the RF in the shack problems.

It really makes sense to have it at the feed point. It's the furthest point from the rig/shack so any radiation from it is also furthest away. If it is very near the shack, the radiation from the coax up to the choke may still be pretty strong in the shack and can disturb some equipment.

I wouldn't expect a common mode choke to kill any receiver noise, just reduce any RF getting into the shack and getting into the rig or computers etc.

A good line filter may do well in reducing receiver noise.

<blockquote data-quote="Hurricane145" data-source="post: 787622" data-attributes="member: 21302">I had a commercially made Common mode choke some years ago. I first placed it just outside the shack and there was little difference. Then I added a long piece of coax and set the choke way out in the yard and it did make some difference but the added coax may have done that, not sure. I eventually added one I made up at the feed point of my 5 band quad and that solved all the RF in the shack problems.It really makes sense to have it at the feed point. It&#039;s the furthest point from the rig/shack so any radiation from it is also furthest away. If it is very near the shack, the radiation from the coax up to the choke may still be pretty strong in the shack and can disturb some equipment. I wouldn&#039;t expect a common mode choke to kill any receiver noise, just reduce any RF getting into the shack and getting into the rig or computers etc.A good line filter may do well in reducing receiver noise.</blockquote>

[QUOTE="Hurricane145, post: 787622, member: 21302"] I had a commercially made Common mode choke some years ago. I first placed it just outside the shack and there was little difference. Then I added a long piece of coax and set the choke way out in the yard and it did make some difference but the added coax may have done that, not sure. I eventually added one I made up at the feed point of my 5 band quad and that solved all the RF in the shack problems. It really makes sense to have it at the feed point. It's the furthest point from the rig/shack so any radiation from it is also furthest away. If it is very near the shack, the radiation from the coax up to the choke may still be pretty strong in the shack and can disturb some equipment. I wouldn't expect a common mode choke to kill any receiver noise, just reduce any RF getting into the shack and getting into the rig or computers etc. A good line filter may do well in reducing receiver noise. [/QUOTE]

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