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 [email protected] 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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Dave,

I have the same antennas mounted in the "X" orientation you describe. On the 2M antenna, I changed the mounting of the element with the coax connector so that it points towards the front of the antenna instead of the rear. That makes it easier to route the coax up the boom to the cross-arm.

Make sure you follow the mounting suggestions in Kent Britain's article mentioned by Gary, KK0CD, and center the cross-arm between the 2M elements.

In my case, I took the coax off the rear of the 70cM antenna as recommended by M2. I use a support similar to the one recommended by Norm to bring the coax back to the cross-boom. The spacing between the 70cM elements is really small, so it is much more difficult not to affect the pattern.

I would avoid the 90-degree elbows, as you'll suffer additional connector loss. Some of them contain a hairpin spring for the center conductor to make it less likely that the internal connection will flex and break. That's a great idea at HF, but acts like an RF choke at UHF, making the loss even worse! :-(

73, Steve N9IP -- Steve Belter, [email protected]

On Dec 17, 2014, at 5:34 PM, Dave J [email protected] 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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Sent via [email protected]. AMSAT-NA makes this open forum available to all interested persons worldwide without requiring membership. Opinions expressed are solely those of the author, and do not reflect the official views of AMSAT-NA. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb