[TowerTalk] another common mode choke question

[charlie carroll]

So following up to last week's thread, a couple questions that will 
surely get some traffic...

Do we really need common mode chokes on our transmitting antenna? The 
station is located on an island in the Caribbean and the nearest AC 
power is about 2 miles away at an industrial site generating their own 
power.  Commercial AC is probably another 2 miles beyond that.  We 
generate our own power with a couple commercial generators.

 From a noise/interferer perspective, our biggest problem was the 
on-island broadcast station that created horrendous fundamental overload 
problems for our 160/80 receiving circle arrays.  About 2 megawatts ERP 
from that station was causing some real havoc until we added a filter 
before each vertical's preamp and plenty of choking on the feed lines.  
I'm not aware of any other noise issues affecting the station on any band.

With that said, assume that we decide to incorporate CM chokes on the 
low-band transmitting antennas and the higher frequency yagis that do 
double duty.  Do we have chokes only at the antenna's feed point and/or 
have others scattered along the coax feed line, including right at the 
back of the amplifiers?

Thoughts, and any real data would be nice too!

73 charlie, k1xx