[TenTec] OT: Ground Radials at Tower Base

[Mike Gorniak]

Actually, radials are fairly ineffective for lightning protection. What 
works is ground rods. Last year I worked on an AM radio station that had 
a full 120 radial ground system at the base of it's tower. Every 
lightning storm that came by destroyed some FETs in the transmitter PA. 
I added four ground rods, each about 10 feet away from the base of the 
tower. These were bonded to the tower base via AWG 00 stranded copper. 
The wire to ground rod connection was cad welded. Stainless steel lugs 
at the tower base insulator's lower flange handled the tower 
connections. I've seen this tower take a direct lightning hit, but the 
station has had no transmitter damage since this modification was made 
over a year ago.

Obviously, the radials are critical to the performance of the antenna. 
But it's the ground rods that protect the station from lightning damage.

73,

Mike
NM7X

----- Original Message -----

From: "Ken Brown" <ken.d.brown at hawaiiantel.net>
>
> >>> The ONLY benefit of a connection to earth is lightning
> >>> protection.
> >>>
> >>>
> > Maybe so, however the question was about adding radials. There is
> > definitely more benefit from adding radials to a vertical antenna
> > system than just improved lightning protection. Perhaps no
> > reduction in received noise, likely an increase in both received
> > signals and noise, and almost certainly a transmitting efficiency
> > improvement. Of course this depends on the existing system you are
> > adding radials to.
> >
> > DE N6KB
> >


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