Thanks Tom for the explanation. As always, this is a learning Reflector. Part of my location involves potential BCB, power line, adjacent home electronics, and of course the legal limit transmissions close to the loop/feed/rotator controller. Common mode supression is an absolute requirement on all lines.
As to it's +- effect on the loop, well, as I mentioned, it was a shotgun process during the installation. Without common mode filtering on all cabling I couldn't operate. Such is the dilemma of the city dweller who has an S4-7 noise floor depending upon season. It's substantially worse in winter as explained below. I'm told that the effective RF ground in these parts of Alaska is 15+ meters down, and it'll find a way into the shack unless crowbarred at the door. Ground rods surrounded by 4-5' of winter frost and non-conductive soils are useless. 73, Gary NL7Y > This doesn't mean loops will never work, or loops with poor feed systems will > never make people happy. It just means it is almost impossible to correct a > bad feed design by stringing beads or winding conventional chokes, even if > you get up to 5,000 ohms. It is always far better to make the antenna with a > correct feed system, because a proper feed has far less common mode response > without any common mode foolery. > > 73 Tom All good topband ops know how to put up a beverage at night. _________________ Topband Reflector
