Re: [TowerTalk] Station Ground

[Gary Schafer <garyschafer@comcast.net>]

Tom Rauch wrote:
> > > With a common buss bar you have ground loops between
> pieces of
>
> > > equipment. If a surge, lightning etc. should get through
> to one piece of
>
> > > equipment it will hopefully exit via the ground to the
> ground window.
>
> If you build your station to code or use common sense on
> external cable and power entry that will never be a major
> issue.
>
>
> > > If there is a common buss bar the surge can enter
> another piece of
>
> > > equipment and go through it via the ground connection on
> it's way to
>
> > > ground. The ground lead from the buss bar will always
> have some
>
> > > impedance so it will be somewhat above ground with a
> surge.
>
> That's generally NOT how it works. The path isn't a loop
> from one piece of equipment to another via a ground buss
> connection, it's generally from the improperly installed
> antenna feedlines to a power line or telco ground through
> the equipment.
>
> The station ground should be neither for RF or lightning. It
> should be for safety.
>
>
> > > With individual ground leads to the ground window there
> is no loop
>
> > > through other equipment. Not always doable but it is the
> proper way.
>
> Not true at all. There are many paths between equipment in a
> typical station. That's why a good low resistance ground
> buss is generally a very distinct advantage.
>
> 73 Tom

It all depends on what you are trying to accomplish. If you are only 
worried about a safety ground then the "green" equipment wire ground 
should be sufficient if all is "properly installed" as professed. But we 
all know proper installation of all equipment is rather rare.

If you are wanting a true single point ground system to help with 
lightning suppression then doing as I described is the proper way to do 
it. You do not want ANY alternate path into any equipment chassis.
As I said it is not always doable though. In the case of most ham 
equipment it is very difficult to achieve. The transceiver is always 
tied to the amplifier via several cables at the operating position etc. 
In this case both should be bonded together and then to the ground window.
If there is say a 2 meter transmitter near by without connections to the 
hf equipment it would be beneficial to have its own ground lead to the 
ground window.
That will further isolate each equipment by not providing a second path 
for any lightning to exit through some other equipment.
Probably in most typical ham shacks it will be impractical to do 
separate leads back to the ground window. I am just pointing out the 
ideal protection scheme for equipment survival.

73
Gary  K4FMX



_______________________________________________

See: http://www.mscomputer.com  for "Self Supporting Towers", "Wireless Weather Stations", and lot's more.  Call Toll Free, 1-800-333-9041 with any questions and ask for Sherman, W2FLA.

_______________________________________________
TowerTalk mailing list
TowerTalk@contesting.com
http://lists.contesting.com/mailman/listinfo/towertalk