K7LXC@aol.com wrote:
>
> In a message dated 2/25/2008 5:38:57 P.M. Pacific Standard Time,
> towertalk-request@contesting.com writes:
>
>
>> Could someone please explain how you can ground a coax shield, on a
>>
> continuous run down a tower, without letting moisture and humidity get
> into it? Thanks!
>
>
> Commercial ground kits include a bunch of butyl rubber vapor wrap
> and 2" wide electrical tape. It's pretty easy to do with the right
> materials.
>
> You cut the jacket away, attach the ground wire and weatherproof.
> And no kinks in the ground wire - just a sweeping run to the attachment
> point.
>
> Commercial ground kits use compression for the shield connection.
> Trying to ground a small cable like 1/2" coax isn't as easy as the bigger
> cables.
>
I'd call that an understatement<:-))
However with a bit of ingenuity and using the appropriate size of copper
pipe or tubing it's not all that difficult to make some good looking
ones that work well.
Take a length of the copper pipe (say 6" long) or tube with an ID about
the same or *slightly* larger than the diameter of the coax with the
jacket removed. Split the copper tube or pipe lengthwise (IOW saw it
into two mating pieces). Solder/Braze the ground wire *lengthwise*
onto the outside of one half. Clamp it to the braid by wrapping the
sections with the rubber vapor wrap and tape which also water/moisture
proofs the connection.
This approach is actually easier to do on the small cables we typically
use than some of the commercial kits.
The most difficult part with the really small cables such as LMR 240 is
removing the jacket without ruining the braid. RG-8X cables with both
single and double shield are easier than the 240. Carefully *score* the
jacket with the tip of a box cutter and apply pressure to cause the
jacket to split. Don't let the blade penetrate through the jacket to the
braid which is very fragile.
I don't currently have photos of any I can show that would give any
meaningful information, but if my memory holds long enough I'll try to
make up some (along with photos) for the feed lines to the sloping
dipoles I'm installing and the ones for the runs to the arrays "up top"
73
Roger (K8RI)
>
> Cheers,
> Steve K7LXC
> TOWER TECH
>
>
>
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