You know, this preoccupation with ground rods sort of makes sense if you follow it's history back to where it began.
Ground rods were 'born' during the time Mr. Edison tried to get New York wired for DC commercial current distribution. DC, instead of AC current distribution as it is now, was a very dangerous proposition, more dangerous than AC. So, to sort of keep things 'safe', a rod was driven into the ground at each site of use (ground rods). That wasn't all that bad of an idea, and it was continued when power distribution was changed to AC. (Those dang things really have been around for over a hundred years)
If you will do some checking, the early means of grounding for radio systems were ground radials, not ground rods. They worked just fine, but were a bit of a 'P.I.T.A.' to install! So, someone did some associating, thinking about the power systems etc. Then figured, that's sure easier than burying a bunch of radials, and tried it. Hey, it worked! Not completely the same thing, but it certainly wasn't all that much different electrically. So RF ground rods were 'born'.
One of the things all them guys back then didn't consider was the orientation of the distribution systems (electrical and RF) were almost completely opposite of each other. Power lines were horizontal. RF systems (vertical antennas) which used grounding were vertical. Changing orientation of the applied signal between the same 'parts' of the system really does do odd things. It get's sort of complicated to try to explain electrically so I'm not even going to bother trying. It IS there though.
So to correctly use grounding there are two things you should really try to keep straight, the ground should be close to the radio so keep bad stuff from happening there (I don't like being shocked), and the 'orientation' of the grounding device should be kept oriented correctly. It really isn't that difficult and more people really ought to try it. The simple means of doing both of those things is to drive that ground rod through the face of the radio (to maintain proper orientation), and to center that ground rod left/right and up/down, through that radio, to maintain symmetry. Works great every time...
Gotch'a!
- 'Doc
Thanks for the help 8)