[Elecraft] Is there a "grounding" Elmer on line?

[N2EY@aol.com]

In a message dated 3/23/03 8:55:38 PM Eastern Standard Time, 
info@CasaDeDomitila.com writes:

> This weekend I put up a 20' tall  (homebrew) guyed mast (top of mast is 38' 
> off the ground and is about 5 feet above the tree line) on my roof that 
will 
> secure one end of a 102' G5RV for the K2 (#3346) I am building and a 
Diamond 
> HV7A on top for a Quad band Yaesu FT-8900R.  I need to be comfortable with 
> the grounding and lightening protection before I run the cables into the 
> shack.

I assume this is a metal mast, made of TV masting or similar.

>      One question is , can the same ground system be used for general 
> grounding and for lighting protection? 

See the QST articles mentioned by another responder. Also check out the 
PolyPhaser website. 

> Can a #10 solid copper wire tied to 
> the base of the mast and run to a 5/8" grounding rod protect from lighting? 

I would not use anything lighter/smaller than #6 wire from the bottom of the 
mast to the ground rod. 

It is difficult to give general answers without knowing things like ground 
composition and conductivity. However, the following rules apply generally:

- Lightning behaves like a very big RF pulse, so conductor surface area is 
very important (skin effect).
 
- Anything that adds even a tiny bit of inductance or resistance to the 
ground path is a very bad thing. This includes things like sharp bends in a 
ground wire.

- Soldered/crimped connections are OUT. Only substantial bolted or welded 
(including Cadweld) connections should be considered for lightning protection 
use.

- There are lots of ways to get a ground connection, and they have to be 
tailored to your installation.

- It is alaways a good idea to design the shack so that disconnecting the rig 
is easy.

Visit your local Home Depot or equivalent and look around the electrical 
department. They have substantial ground rods (typically 8 or 10 feet long), 
#6 and heavier bare copper ground wire, and suitable clamps. Electrical 
supply houses are even better sources. But do not expect the salesfolks to be 
knowledgeable about your application, because they are primarily interested 
in service neutral grounding, not lightning protection.

Driving ground rods can be made simple by the "Kango hammer" (jackhammer) 
method, if you have access, but if not, try a fence-post driver. This is a 
piece of heavy pipe with a cap on one end and handles on the sides. Slide it 
over the top of the ground rod and move briskly in an up-and-down motion to 
hammer the rod. Easier than trying to hit a wiggling ground rod end with a 
sledge.

73 de Jim, N2EY