[amsat-bb] satellite flexible rotor-section coax question

[Miles]

Antenna configuration:

Yeasu Azimuth and elevation rotor.

Solid fiberglass horizontal mast, 2.00 diameter, 14 feet long.

M2 2-meter (20 element) on one end, M2 440 (44 element) on the other end.

I installed two 80 foot sections of LMR 600-UF from the shack to top of 
the tower.

I have the option of installing a tower mounted preamp, but just added a 
Female to female N-Connector at this spot.
Preamp are in the Shack.Higher loss, but I have not Fried a Preamp in 15 
years.

I installed 2, 20 foot sections of LMR-600-UF is used to go around the 
AZ/EL Rotor to the antennas (one for each ).

LMR-600-UF is flexible enough to be used around rotors.Just following 
the bend radius rules for this cable.

Issues:

I used high quality UV-stabilized tie wraps to attached coax to Masts 
and antenna booms.
After 10 years of usage, my SWR went bad on the 2-meter beam.

The vibration and flexing of the antenna boom and rotor masts caused the 
tie wraps to "SAW" through the outer layers of insulation on the LMR-600-UF.

I had to replace the two 20 foot sections of LMR-600-UF.They were full 
of water.

Also the 2-meter tuning stubs were also Sawed through by the tie wraps.

I replaced all of the 10 year old damaged cables.

I reinstalled by using Spiral-Wrap over the sections of coax that were 
going to come in contact with tie wraps.
I would add about 4 inches of Spiral-Wrap and then UV black tape to hold 
the Spiral-Wrap in place.Then I installed 2 tie wraps over Spiral-Wrap.

New Rules.

Never use a Tie-wrap on a bare section of coax insulation (if there is 
any chance of vibration or flexing).
Always cover the coax insulation with Spiral-Wrap to prevent the 
tie-wrap from sawing through your coax.



On 8/26/2018 8:24 PM, David J. Schmocker wrote:
> Hello:
> New to satellite communication I plan to construct a fixed station to work
> satellites.
>
> I am looking to identify best type of coaxial cable to run from my VHF/UHF
> antennas around az/el rotors to the preamplifier (located on the fixed
> mast/support).
>
> Most important coaxial cable requirements include:
>
> Highly Flexible (in upper midwest climate: temperatures range from �15 deg
> to +100 degrees F) in Repeated (continuous) flexing
> Low Loss (while super flex Heliax would be my preference, it�s not designed
> for repeated flexing this application sees
> Full shielding (preserve S/N and overall system noise figure).
>
> I can compare the loss values from manufacturer data sheets; my main
> interest here is to learn what type of cable has withstood the repeated
> (continuous) flexing required to work satellites?
>
> What cable type do you recommend based on your experience?   Thank you   73,
>
> Heliax Superflex?    Times Microwave LMR-600UF?   EcoFlex 15 Plus?   Belden
> 9913Flex?   Something else?
>
> David J. Schmocker, KJ9I
>
>
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