[amsat-bb] Coax routing question

Lizeth Norman normanlizeth at gmail.com
Thu Dec 18 02:44:04 UTC 2014


Dave,
I use pvc pipe in parallel to each antenna that routs the coax (zip
tied in place) from the rear of the boom to the cross arm. Then in to
the center and down with the other cables. Had a bunch of problems
with the coaxial cable hanging up due to the droopy loops required for
elevation cable travel. The preamps were mounted in a box on the side
of the tower which caused much of the trouble. Now they are mounted on
the cross boom. Am using 9913F7 for jumpers. lmr-400 or ldf450a come
from the tower to the shack.

Did have to mount the antennas in a way that balanced the array. Not
exactly as pictured.

Live in FL, so the pvc won't last long. Am looking for a replacement.

No problems in 6 months. It gets used pretty heavily. Rotator is a
G5500 split in a Rohn 25 flat top section with tb-3 thrust bearing /
rotor shelf configuration.

Do bear in mind that the dc return for the polarity switching is the
shield of the coax.

Be looking for you.
Norm n3ykf

On Wed, Dec 17, 2014 at 6:34 PM, Dave J <ddjulian54 at yahoo.com> wrote:
> I am assembling a satellite antenna system using the M2 2MCP22 and 436CP30
> circularly polarized antennas with polarity switches and a fiberglass cross
> arm. The M2 instructions specify the feedline going off the rear of the
> antennas. Mechanically I would prefer to route the feedline and polarity
> control up the boom to the cross arm. I plan on mounting the antennas in a
> cross pattern with no element parallel to the cross arm. Since the RF
> connectors face the rear I was planning on making a hairpin loop at the rear
> of the boom or using good quality 90 degree elbows. Just wondering if folks
> have had experience setting things up this way and what effect (if any) this
> would have on performance.
>
>
>
> Thanks and Happy Holidays
>
> Dave WB9YIG
>
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