Brian Smithson wrote:
>
> Greetings!
>
> I have a good length of 7/8" cable hardline - bare aluminum shield and
> center conductor, with a foam dialectric. No connectors. I'm getting
> ready to put up a tower and I'd like to finally make use of it - can > you
> help me with connectors/transformers for this? I assume it is 75 ohm.
>
> Tnx es 73!
>
> Brian Smithson
First of all Grian, don't assume anything. 3/4" hardline is big enough
for you to measure the od of the inner conductor, and the id of the
shield. Then get out your handbook and plug the figures into the
simple formula they supply. You also need a dialectric constant, but
in reality, just choose a similar one from the information given. You
will then know whether the stuff is ~70 ohms, or you may get a pleasant
surprise and hit the jackpot.
As for connectors, I have both 3/4" 70 ohm and 50 ohm stuff. Any
hardware store will have a brass or copper 3/4" to 1/2" reducer,
and it may be either threaded on the 3/4" end or use a compression
fitting. If threaded, simply slowly use the thing to cut threads in
the aluminum. ( or invest in a $10 dohicky which cuts threads )
Simple enough to just use a SO-239 in the 1/2" end, plenty of NOALOX,
and then weatherproof it.
I put up a 6" section on a fence post, and left it there for about
5 years. Took it apart, and it was as bright and shiny as the day I
built it.
Good Luck
Ed
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