[TenTec] Earth those feeders

[Stuart Rohre]

I want to clarify my point in saying to AVOID leaving ungrounded feeders 
around a shack.  If they are disconnected and laid out on the operating 
desk, they might move over and touch a grounded metal chassis or case 
during a surge event.

The cases should, and are grounded by a proper grounding protocol. 
(Three wire AC cords for units containing AC supplies).  But the 3 wire 
cord should not be carrying the currents that might come in on a coax. 
And ultimately the grounds should be joined at the Service entrance by 
external ground rods, and adequately large earthing conductors, and even 
joined to a halo ground around the building in the ideal case.

You don't want the grounding to be casual, during a surge, to a chassis; 
you want a place to plug feeders into a dedicated ground bus that then 
is directly connected out side to earth with a large down lead.

High currents through coax can cause the coax to jump or move, and the 
free end might flop around and carry a surge to ground through a smaller 
conductor, (the radio) than a properly grounded coax. You DON'T want the 
end of a coax connector arcing to your other equipment.

Surprised at the statement coax can move?  We had a high voltage, high 
current plasma generating experiment in the University laboratory.  When 
we dumped a room full of racks of capacitors into the plasma tube,
the coaxes acting as high voltage cables jumped a couple of feet up and 
down although tied off, before crossing the ceiling between rows of racks.

That was a life lesson not lost on me when later I constructed lightning 
simulators for testing Army field electronics.

-Stuart Rohre
K5KVH