rotator coax
 

hi

Was going to put up some antennas turned via a rotator.

Normally I guess people use some 'flexible' type coax like a
RG213

Wondering if cost was no object is there some coax that is
better rated to withstand this type of repeated flexing ??


Thanks

rotator coax
 

ml wrote:
hi

Was going to put up some antennas turned via a rotator.

Normally I guess people use some 'flexible' type coax like a
RG213

Wondering if cost was no object is there some coax that is
better rated to withstand this type of repeated flexing ??


Thanks
Hi Ml:

There used to be a "type" of RG-8 coax called "superflex" that was much
more flexable than standard RG-8 (this was back when RG-8 was still a
mil standard)but I've not seen it for some time. But I've used RG-213
for years with no problems just remember to leave a big enough loop so
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

rotator coax
 

In article ,
John Passaneau wrote:

ml wrote:
hi

Was going to put up some antennas turned via a rotator.

Normally I guess people use some 'flexible' type coax like a
RG213

Wondering if cost was no object is there some coax that is
better rated to withstand this type of repeated flexing ??


Thanks
Hi Ml:

There used to be a "type" of RG-8 coax called "superflex" that was much
more flexable than standard RG-8 (this was back when RG-8 was still a
mil standard)but I've not seen it for some time. But I've used RG-213
for years with no problems just remember to leave a big enough loop so
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??


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



thanks

rotator coax
 

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.

rotator coax
 

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.

rotator coax
 

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.

It too has a foil shield. It is just like LMR400 but with a more flexible
jacket and stranded #10 center. Belden 8913 is just like 9913 without the
foil.