[TowerTalk] Replacing station ground
john at kk9a.com
john at kk9a.com
Wed May 30 17:15:14 EDT 2018
I purchased six (one for each band) of the Array Solutions protectors that
Jim mentioned. https://www.arraysolutions.com/as-303u. They are indeed a
nice design and I too like the drain feature.
I do not use my station very often and my lightning protection is a work
in progress so I leave the cables disconnected in an outdoor Hoffman
enclosure. There are burn marks inside the enclose so my towers are
apparently getting hit on occasion.
If you do not have a whole house surge protector you may want to consider
adding one as voltage will be induced into your house wiring during a
Jim Brown K9YC wrote:
I've used two different solutions to get cables into the shack. The
first was to mount feedthrough Polyphaser arrestors on a copper panel
mounted in a cutout in the wall. Neighbor K6XX built the panel in his
shop and helped me mount it and mount the arrestors. The second was a
couple of Hoffman boxes mounted to the wall, one with terminal strips
for control cables with provisions for arrestors on each conductor, and
the other with the arrestors that Array Solutions sells. Each box has
one or more feedthrough PVC conduits to get through the wall into the shack.
I strongly prefer second arrestor solution for two reasons. First, the
Polyphasers do occasionally go short circuit, either from a lightning
hit or operator error (TX into the wrong antenna). In addition to cost
(they cannot be repaired by replacing the GDT element), they are a major
PITA to replace. Second, I much prefer the circuit used in the Array
Solutions arrestors, because it is far more likely to discharge any
gradual charge buildup before it reaches a point that triggers the GDT.
KF7P makes some nice custom Hoffman-style boxes for the arrestors he
sells, but neighbor W6GJB designed a very nice (and simple) mounting
method to increase the number of arrestors that can fit in the box, and
make it easy to replace a blown GDT. With all hinged cover Hoffman
boxes, cables enter the bottom of the box through strain relief fittings
sold for use in power system box knockouts, and cables have tape or
heatshrink to build up their diameter to minimize the opening for
insects. Boxes are purchased with the optional steel panel, arrestors
are mounted to the panel, and the panel is bonded to the ground system.
My shack utilizes both the Polyphaser panel and this newer Hoffman box,
and both are bonded at the same point.
I've photographed the box, and at some point I'll write it up and put it
on my website.
As to #4, W8JI has observed that this should not be necessary if
everything is properly bonded both inside and outside the shack.
73, Jim K9YC
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