I have a full set of suppressors at the tower and shack ends. I think this
is important for protecting long cable runs between the tower and shack. In
my case, it's 225 feet for one tower and 265 feet for another tower. Seems
to me that long cables will have greater impedance, and that a surge
originating at the tower won't "see" the suppressors at the shack end and
could damage the cables by punching holes in the insulation or dielectric in
order to find a shorter path to ground.
It also seems to me that suppressors at the base of the tower help protect
equipment and ungrounded cables on the tower. For example, a suppressor
providing a low impedance path to ground for a coax center conductor may
prevent the charge from punching a hole in the dielectric in order to get to
the grounded shield. I could be wrong about this, but it seems logical.
Again, the long cable runs to the suppressors at the shack is the reason.
With short runs, I'd think the cable impedances would be low enough that the
suppressors at the shack end could protect them.
Of course, as Roger will point out, it all depends on the nature of the
strike...
73, Dick WC1M
> -----Original Message-----
> From: Richards [mailto:jruing@ameritech.net]
> Sent: Sunday, March 01, 2009 12:46 AM
> To: CRAIG CLARK
> Cc: towertalk@contesting.com
> Subject: Re: [TowerTalk] lightning protection
>
> Is there any reason one would not want to put protective devices at
> BOTH
> the tower AND the entry point?
>
> Unlike wearing belt and suspenders... it might be a good idea...?
>
> =============== K8JHR =====================
>
> CRAIG CLARK wrote:
> > "Techs from Poly Phaser said at the base of tower, "
> >
> > In most ham installations, however, the towers and antennas are
> often some
> > distance away
> >
> > That's why I have all my protection where the feed and control lines
> enter
>
> ==========================================
_______________________________________________
_______________________________________________
TowerTalk mailing list
TowerTalk@contesting.com
http://lists.contesting.com/mailman/listinfo/towertalk
|