Topband: Outdoor cable trunking - opinions pse

[Tom W8JI]

> Lightning strikes aren't common round here, and if there is one it's more 
> likely to damage the trees or the house.
>

I don't want anyone to get the impression the lightning damage I get comes 
from lighting hitting my cables.

The damage I get is from ground loop currents that flow through the cables. 
The current opens the shield inside the cable by melting the foil and the 
shield. The better the grounded, the worse the problem becomes. The most 
unreliable cables I have are the cables out to the elements in my eight 
circle, because it has 6 or 8 buried radials at each vertical. I used to 
lose a cable or two every year.

I fixed it by plowing in a number 8 wire out from the hub to each vertical, 
and using a 50 foot coil of small cheap coax in a sacrificial choke where 
the feed for the eight circle branches off the 1500 foot or so long trunk 
bundle.

Damage to shields has nothing at all to do with direct strikes, but rather 
ground loop currents in the earth when lightning hits within several hundred 
feet of the cable at any point. The better the cables are grounded, the 
worse this type of problem becomes.