[TowerTalk] Radiating Lightning Rod

[Rick Stealey]

 Jim says:
> I run each coax to the bottom of the tower
> and have a 6-8 turn Coax coil on each line before it goes into the equipment
> box at the base of the tower. from there all the antenna coax and control
> cables go underground in PVC pipe and come up in the wall behind my
> operating desk.

If there is lightning induced current coming down the coax lines (in parallel with current coming down the tower legs themselves) the inductance of the coil causes a large voltage to appear across the coil.  This can flash to the tower easily and likely destroy the coax.  
I believe the proper thing to do is to install the coax so it gets grounded right at the tower base.  In other words, assume the lighting current is going to flow on the coax and we want that current to get into the earth by a path that we determine.
Assuming in your equipment box (you didn't say) you are bonding your coax lines to a good ground, then it is likely that the majority of the strike current is dissipating at the tower location and only a small portion will find its way to your house.  But to protect the equipment in the house you really should be grounding and providing lightning arrestors outside, at the point where the conductors enter the house.  

Rick  K2XT

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