[CQ-Contest] Coax Stubs for SO2R

[Roberts, Will]

My switch box is mounted in a crawl space under my house. It is about halfway from the tower to the shack. Most standard T connectors will fit on the switch box if oriented correctly. Could you possibly hang the (coiled up) stubs on the post where your switch box is mounted? My stubs are simply stacked beside the switch box. I have also seen stubs coiled up and put in buckets. I don’t think where they are stored is critical.

73,

Will AA4NC

From: Jeff Clarke [mailto:ku8e at bellsouth.net]
Sent: Wednesday, September 09, 2015 4:52 PM
To: Roberts, Will
Cc: cq-contest at contesting.com
Subject: Re: Coax Stubs for SO2R



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Will and others who suggested putting the stub at the antenna side connectors of your Six Packs.... Are your switch boxes at the top or bottom of your tower or inside the shack? The stubs are actually on your towers?

My box isn't on a tower. It's mounted on post in the woods where my antennas are, maybe 75 to 100 feet away from my shack. The SO239's for each band on a Six Pack seem to be pretty close together on the box. You are able to fit a T-connector and a stub on one of those SO239 positions despite that?

Jeff
On Sep 9, 2015 1:08 PM, "Roberts, Will" <Will.Roberts at duke-energy.com<mailto:Will.Roberts at duke-energy.com>> wrote:
Hey Jeff,

I use only tuned stubs for SO2R with my Six Pak. I don’t have any other filtering. I connect the stubs on the antenna side coax connectors on the Six Pak with one or more T connectors. There is 75’ of coax between the Six Pak switch box and the stations. It seems to work reasonably well. There is a little interstation interference, but most of that is just on harmonic frequencies, so it is manageable. Make sure your stubs are cut well as N3RR mentioned. Mine were cut by W2JVN. Also, make sure that the T connectors are high quality. I had initially used some cheap Chinese T connectors that came apart under the strain of the stubs pulling on them. In one case, a T connector developed an intermittent that allowed increased interference. All replaced by Amphenols now.

73,

Will AA4NC



From: Jeff Clarke <ku8e at bellsouth.net<mailto:ku8e at bellsouth.net>>

To: cq-contest at contesting.com<mailto:cq-contest at contesting.com>

Subject: [CQ-Contest] Coax Stubs for SO2R

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Wondering how those of you using a Six Pack antenna switch hookup your stubs? I have two coax cables from the Six Pack coming into the shack going to each radio. Each station has a multi band Dunestar switchable filter. For the most part the Dunestar works well but since I recently added an KPA500 to my run station, when I'm on 40 meters with the amp it gets into 20 meters on station #2 pretty bad. Are you all using a T connector and have the stubs for each band on a manual multi position antenna switch?



Also does anyone know if the Dunestar's are tuned for a specific part of the band. On 80 meters mine seems to have a very high SWR when I switch it in even though the SWR on the KPA500 looks good.



Jeff