[TowerTalk] ground systems... ferrous conduit

[Jim Jarvis]

Jim, W6RMK provided a link to the FAA's lightning ground and
surge protection standards.  They include a requirement that
cables pass through a grounded 10' long ferrous conduit (pipe),
before entering a structure.

I recall reading that this serves as a choke for current
flowing on those cables.  As a result, I've routed all my
runs through a section of iron pipe, for as long as I can
remember.

On the other hand...I ALSO recall reading comments on here 
poo poohing the idea.  

Comments from someone who really knows?

N2EA
jimjarvis at ieee.org