[TowerTalk] 40M rotary dipole

[Joe Subich, W4TV]

On 9/21/2017 1:35 AM, Stan Stockton wrote:

> So there is no propagation such that Antenna 2 picks up the noise 
 > radiated from Antenna 1, end of which is at most a few inches away?

In practice, it is not *radiated* noise that is of concern.  The noise
on antenna 1 is actually *conducted* into antenna 2 by the bonding of
antenna 1 (the tower) to the "cold" (shield) side of the the feed line.
Proper use of common mode chokes - typically at the bottom where the
feed line leaves the tower, at the top in the jumper at the antenna
feed point, and at the feed line "entry window" - provides several K
Ohms of impedance and reduces that *conducted* noise significantly.

73,

    ... Joe, W4TV