[TowerTalk] Musing on G5RVs, baluns et al......

[Jim Brown]

On 2/3/2011 12:28 AM, Steve Hunt wrote:
> As you realise, adding a choke to the G5RV is not primarily about
> improving the match or saving dB - it's about stopping the ladderline,
> and more importantly the coax, from becoming part of the radiating
> structure.
>
> Chances are the coax comes very close to equipment in the shack/home
> that is susceptible to RFI, and that generates noise on RX; it probably
> then connects directly to the household mains earth. You don't want it
> becoming a part of the antenna!

This is exactly right -- except that common mode current is equally 
possible, and equally undesirable on parallel wire line as compared to 
coax, BECAUSE of the noise coupling issue, AND to prevent the feedline 
from radiating  TX RF where it is more likely to couple to your 
neighbor's stereo rig, AND to prevent it from conducting common mode 
current to the shack, where it excites Pin 1 Problems.

> Varney didn't have that problem - no PCs, digital 'phones, plasma TVs
> etc in his shack when he developed the antenna

Right!

73, Jim Brown K9YC