A good RF ground

From:  Keith Maddox [SMTP:kmaddox-at-burgoyne-dot-com]
Sent:  Tuesday, June 16, 1998 9:39 PM
To:  Tesla List
Subject:  Re: A good RF ground

Tesla List wrote:

> ----------
> From:  Marco Denicolai [SMTP:marco-at-vistacom.fi]
> Sent:  Monday, June 15, 1998 12:39 AM
> To:  tesla-at-pupman-dot-com
> Subject:  A good RF ground
> It's time for my TC to get a good RF ground. I read the Quick instructions
> about 4-5 8 feet copper pipes spaced 8 feet. I understand he meant a kind of
>                        RF GND
>                          |
> _________________________|___________  soil level
>          -----------------
>          |   |   |   |   |
>          |   |   |   |   |
>          |   |   |   |   |
>          |   |   |   |   |
> Has anybody got any other suggestion? Have the pipes to be copper?
> ________________________________________________________________________
>  Marco Denicolai                   Vista Communication Instruments, Inc.
>  Hardware Development Manager      www.vistacom.fi
>  marco-at-vistacom.fi                 Kaisaniemenkatu 13 A
>  fax:    +358-9-622-5610           SF-00100 HELSINKI
>  phone:  +358-9-622-623-15         Finland
>    Remember, Murphy was an optimist! I am not...
> ________________________________________________________________________

  I use a home made ground system for some of my radio work and plan on using
the same ground for my new TC.  It consists of 8 x 8 ft pieces of 1/2" rigid
copper water
pipe (cheaper than soft drawn) buried to about 20 inches deep in my back yard.
The configuration I use is a star.  To get this, I used 4 Tees like this:

I did not cap the ends since the more dirt and moisture around and in the pipes,
the better.  This system has worked great for my radio work as well as a 1KW TC
I build about 15 years ago.  There should be no problem with a system like this
even for a 50KW TC I wouldn't think.

Copper is the best choice for this
since it is a very good conductor.  It has the undesirable property that it
turns very green from corrosion.  Aluminum too will get a nasty coating on it
plus it has the disadvantage that it does not conduct nearly as well as copper.
Gold would be a good choice if it weren't for the cost since is is rather
chemically inert, that's why it is often used for connectors.  Contrary to
(some) popular belief, it is NOT as good of conductor as clean copper.  Silver
is the best conductor but it too suffers from the disadvantage of high cost.
Just use copper pipe as I have done and you'll be real happy with the
performance improvement!

If your ground is very dry, put the sprinklers on it one day before you use it
and it'll conduct like mad!