On 7/17/18 3:13 PM, Jim Brown wrote:
On 7/17/2018 1:50 PM, jimlux wrote:
Yes, you need a choke on the coax at the tuner (which is what forces
the above statement - you don't want currents going down the outside
of the coax).
A choke at the tuner is NOT equivalent to a choke at the feedpoint
(although a choke both places is not a bad thing).
The length of feedline between the antenna and the choke IS PART OF THE
ANTENNA, so noise picked up on that length of line is coupled to the
antenna, then comes back down the line (as a differential signal) to the
receiver.
I agree - I was assuming the "feedline" is short (single digit feet) and
reasonably balanced (so that environmental noise would couple equally to
both sides). And, of course, the tuner itself is sort of an asymmetric
thing, and if it has a conductive box (or a ground plane under the PWB
inside a plastic box), then noise could couple in that way too.
_______________________________________________
_______________________________________________
TowerTalk mailing list
TowerTalk@contesting.com
http://lists.contesting.com/mailman/listinfo/towertalk
|