[TowerTalk] Fwd: Grounding of tower
jimlux at earthlink.net
Fri May 10 15:38:08 EDT 2013
On 5/10/13 9:15 AM, Jim Brown wrote:
> On 5/10/2013 8:58 AM, George Dubovsky wrote:
>> In the case of a radial system on or just below the surface of the earth,
>> one or many ground rods connected anywhere to the rf ground system should
>> not hurt,
> Please remove the phrase "RF ground system" from your vocabulary -- it
> is a false concept, and leads to confusion.
> Rudy Severns, N6LF, has done a lot of work studying radial systems for
> verticals, especially for the lower bands. Rudy has shown that an earth
> connection can significantly degrade the performance of an elevated
> radial system. I suspect he might agree that adding an earth connection
> to the feedpoint of a dense on-ground radial system would not hurt, and
> radials connected a grounded tower certainly have that condition . Earth
> connections elsewhere in the radial system are a bad idea, because they
> disturb (in a bad way) the current distribution along the radial. Rudy's
> published work does a great job of explaining why.
This was also an observation when they were validating NEC3/NEC4. They
modeled worse performance with a set of radials plus a ground rod than
just the radials alone. They were kind of surprised, so they went out
and built a test and verified that it is real.
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