[TowerTalk] spark gap/ insulated tower

[Jim Miller]

Rain, interesting thought.  Can they be mounted horizontally so the raindrop
will not tend to close the gap?  OR the contacts separately mounted up at 45
degrees with the contact points of EACH pointed up so the rain will run away
from the spark gap?  Can they be shielded?  With a plastic soda bottle or a
plastic kit box?

I haven't seen these things but have been considering one and the pictures
seem to be from a museum or belong in a dungeon or something.

73, Jim

----- Original Message ----- 
From: "jim Jarvis" <jimjarvis at optonline.net>
To: <towertalk at contesting.com>
Sent: Monday, October 06, 2008 7:40 AM
Subject: Re: [TowerTalk] spark gap/ insulated tower


>
> Todd wrote:
>
> I recently erected an 80' base insulated Rohn  25G tower.  It is
> guyed with
> philystran cable.  I have been told that I should install a spark gap
> at the
> base insulators.  If this is the case, what should the gap be for such a
> spark gap?  I currently have 2 brass straps 1.5" wide X 1/4" thick
> from the
> top and bottom of the insulators.  The gap is 3/16" wide.  Any advice is
> greatly appreciated.  Todd,  WA7U
> -0-
>
> Todd,  it somewhat depends on the shape of your gap materials.
> Broadcast towers have balls,  the spacing of which can be varied,
> depending
> on power levels involved.
>
> 3/16" may be just fine for you.   You don't want it arcing over at
> full power, even when
> it's raining.   But you want it spaced as closely as possible, beyond
> that.
> The arc-over situation will vary, depending on whether you have
> pointed metal
> to pointed metal, or to a flat plate, or other shape.
>
> So, no simple answer will be correct.
>
> N2EA
>
>
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