The old rule of thumb for lightning protection from over head
dissipation devices (high metal roofs, lightning rods, grounded towers,
etc. is a 30 degree cone angle. This is NOT a guarantee but a
tendency. I think more is better and would not find fault with a ground
wire a ways above coax or control leads but would encourage ground rods
along the way so as to not encourage a great deal of coupling between
lightning generated ground wire and "other" conductors below it.
Patrick NJ5G (now stand by for a total debunking of my comments...)
On 1/28/2015 12:30 PM, David Gilbert wrote:
I don't have the expertise to be sure about it, but it always seemed
to me that it would be best to run the ground wire (grounded at both
ends and maybe a few places in between) in the same trench as the coax
... but some distance above them ... in order to provide a sort of
shielding effect for the coax against induced currents from nearby
lighting bursts. I was once told that the electric utilities run a
ground line at the top of utility poles above the actual power lines
for a similar purpose.
Possibly induced currents in the ground wire would still couple to the
coax anyway, but I certainly don't see how running the ground wire
with the coax would be any worse than running them separately.
73,
Dave AB7E
On 1/28/2015 8:43 AM, Cox, Norman R. wrote:
Dear Group:
I am now ready to connect the tower grounding rod network to
the shack grounding system. The crank-up tower is about 30 feet from
the shack. Is it preferable to run the ground connection between the
two along with signal cables? Or is it better to run the grounding
connection not so close to the signal cables? I've seen people do it
both ways, and can see a possible benefit either way, but a lightning
strike could throw either idea out the window.
Thanks,
Norm
KE0ZT
_______________________________________________
_______________________________________________
TowerTalk mailing list
TowerTalk@contesting.com
http://lists.contesting.com/mailman/listinfo/towertalk
_______________________________________________
_______________________________________________
TowerTalk mailing list
TowerTalk@contesting.com
http://lists.contesting.com/mailman/listinfo/towertalk
_______________________________________________
_______________________________________________
TowerTalk mailing list
TowerTalk@contesting.com
http://lists.contesting.com/mailman/listinfo/towertalk
|