Thread: rotator coax
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Old August 2nd 09, 01:07 AM
n9zas n9zas is offline
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First recorded activity by RadioBanter: Jun 2009
Posts: 155
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Quote:
Originally Posted by ml View Post
In article ,
"JB" wrote:

the coax is not stressed to much. The kind of coax with the foil under
the braid is NOT good for this loop.


John Passaneau W3JXP

Hi

Thank you very much for responding. was hoping more might respond
to what I thought was a fair question.

Interesting wonder why you don't recomend the foil type I guess the
extra flexing would damage it??

Yes. Not only does the foil shield break up, but the abrasion between the
dissimilar metals causes noise

Perhaps i can just find some double braided shield then...

A good 95% + shield like Belden 8214 or eq. foam type with stranded center
conductor is the best. Extra shields will complicate matters. If you have
multiple runs, the crosstalk between cables will me much less than the
antennas talking to each other anyway unless you have a lot of vertical
separation. It is good to use double shielding on duplexers and hardline on
fixed antennas. When going around a rotor, you will have maximum life if
you provide strain relief and broad loops like the remote broadcast trucks
do. The coax will go bad at the loop first. Another answer is to use
hardline up the tower and 8214 or RG-214 and N connectors for the rotor
jumper, and replace it occasionally. Of course the connectors must be
strain relieved, wrapped and well sealed to avoid any mechanical disturbance
or water intrusion.

thanks much for a ll the tips
You might want to check out Belden 9913F (flex) which is a low loss coaxial cable which very well at frequencies up to 1ghz.
N9ZAS.
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