[Elecraft] Artificial RF Ground

[Jim Brown]

On Thu, 2 Apr 2009 17:42:43 -0400, NG3V wrote:

>All this talk of RF grounds has re-kindled my desire to run more than 10
>watts without RF feedback in the shack (yeah, I know 10 watts is enough, I
>just like the ability to have more).

There is a MUCH better (and MUCH LESS EXPENSIVE) solution. Simply wind a 
coaxial choke around a 2.4-inch toroid, following the instructions in the 
"Choke Cookbook" section of 

http://audiosystemsgroup.com/RFI-Ham.pdf

Place this choke at the feedpoint of your antenna. It will do a VERY good 
job of isolating the coax from the antenna. 

>Anyway, my shack is in an enclosed room in the basement with no direct
>access to the outside world.  My antenna is a ground-mounted vertical 
>about 15 feet from the house with buried radials.  The feedline is laying
>on the ground.  Poor arrangement

Huh? There's nothing wrong with this arrangement that I can think of. It 
is, of course, important that the shield of the coax have a very short 
connection to earth for lightning protection (that is, a ground rod), and a 
short, beefy connection between that rod and the ground rod(s) for your 
electrical system and telephone system and CATV system. These connections 
should be outside your building. 

There is NO need for an ADDITIONAL connection to the earth inside your 
shack, but the connections listed above are VERY important for lightning 
safety. 

The confusion evidenced by your "poor arrangement" statement is why I so 
strongly object to ANY use of the words "RF ground." The many complex 
electrical and radio sytems in a modern aircraft have NO connection to the 
earth, but they work just fine! And that 400 Hz whine you hear when you 
plug your headset in -- that's a pin 1 problem in their audio system, again 
the result of fuzzy thinking about "ground."   

73,

Jim Brown K9YC