[Towertalk] Lightning Ground

[jljarvis]

I read the Polyphaser piece with some amusement.
He's right-on with what he's proposing, but as many have
observed, we don't need to be up 24/7, and the thorough
approach is not cost effective.  Try and get your cable
TV vendor to comply with it!  They want no part of your
ground.

I've developed a few rules, over the years, with which
you might disagree, but for what it's worth:

*  You CANNOT protect against a direct hit.
	It's an illusion.  You CAN protect against
	secondary strikes, or induced currents in 
	house/phone/antenna wiring from nearby hits.  

*  OUT THERE is a better place for lightning, than in here.
	I disconnect the entire shack, including
	ground, when it's not in use, or I'm not
	present.

*  The tower itself uses a decent lightning dissipation
	ground.  

*  Everything coming from the tower goes through two chokes, made
	of 5' lengths of simple 2" iron pipe.  One near the tower base, 
	the other near the service entrance to the house. Coax runs on 
	the ground. The downstream end of each of these pipes is grounded 
	to its own rod.  

	Whether the inductance of these pipes forces the lightning to 
	arc to ground at the HV end or not, I'll leave to you to decide.
	It seems like a plausible theory, and I'm sticking to it.

*  All coax and rotor/switching cables terminate on a single metal
	panel service entrance.  This is also grounded.  MOV's and
	gas-discharge tubes (ICE) handle protection on this panel.

*  All cables are disconnected when Tstorms approach.  


That said, In the interest of getting the system working quickly, as
a Vermont winter approached, I broke most of my rules.  Grounding the 
tower and disconnecting all cables were the only exception. This Spring 
I discovered that all pl259's had blackened due to arc-overs.  As I 
wasn't running high power, this could only be attributed to lightning.

This season,  my rohn 45 is coming off the house.  Another tower is 
going up 100' away, and we'll follow the rules to the letter.  

Jim n2ea