View Single Post
  #9   Report Post  
Old June 28th 06, 04:28 PM posted to rec.radio.amateur.antenna
Jimmie D
 
Posts: n/a
Default Antenna tower Grounding


"Bob" wrote in message
. com...
What you described will do little for lightning protection except give you
a false sense of security. Surviving a direct hit requires much more
grounding and proper treatment and routing of all cables into the house. I
would highly recommend spending $20 on PolyPhaser’s book of info or at
least reading the tech notes on their web site.
Bob


Jeff Dieterle wrote:
I'm installing a 60ft self-supporting tower. It will have a vhf/uhf
antenna with rotator and a couple of satellite dishes on it. The tower
will be set in a concrete apprx. 4'x4'x4'. Is driving a copper clad
5/8"x8ft ground rod and attaching a #6cu ground wire to the tower leg
sufficient.
I live in a heavily wooded area and have lost several modems to lighting
strikes. Now when it looks like thunder 2 states away I unplug them on my
computers and Directv receivers.


The Polyphaser book was the main source of data used by the company I work
to redo the grouding at many of its sites. Most sites that were being
knocked off the air nearly every time a storm came through have never had
such an outage since the new grounding was installed. $20 bucks well spent.
Installing the new grounds will cost a lot more. One of the big impovements
was to use low inductance braided cable run all the way from the air
terminals at the top of the towers to the ground rods/system. Prior to this
the tower was grounded by a cable connecting the base of the tower to the
ground system. Much more was done which included grounding coax and and
control cables where they entered the building. This was done prior to the
modification but there was now a much larger emphasis on LOW INDUCTANCE
connections. Typical change made. Coax shields were attached to ground at
the point they enter the building prior to the mod. This connection is still
there but made through copper straps instead of cables and the coax is also
grounded just before it makes a 90 degree bend to leave the tower and enter
the building. Going from several lighting related outages a year to none in
several years is a big improvement.