"Ian White, G3SEK" wrote in message
...
Richard Clark wrote:
On Wed, 08 Sep 2004 21:24:53 GMT, "Jimmie"
wrote:
They are not interested in a specific value in most cases.
...
Ground meets spec or it doesnt.

Without a specific value, how do they (we) know it meets spec?

For a mains safety ground, the bottom line is: is the ground resistance
low enough to blow a fuse in the live rail? If the answer is no, you're
heading for a fire, so there is some surety in verifying that a fuse
really will blow.

On the other hand, for an RF ground it's a lousy test.

True enough on the RF , but no worse than any other test meant for primary
power. While this test alone does not insure a good RF ground and it is a
good first test to let you know you are going in the right direction. If
this test is bad for 60Hz AC then RF ground is probably a lot worse. VSWR
reading for my antenna is 1.25:1 at the resonant frequency of my antenna.
Given the inaccuracies of SWR meters I figure I have a ground resistance
some where between 3 and 10 ohms. Maybe one day I will try to to get a more
accurate reading when other things in my life take less priority.



--
73 from Ian G3SEK 'In Practice' columnist for RadCom (RSGB)
http://www.ifwtech.co.uk/g3sek