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Author Topic: Remote control head caable  (Read 1198 times)
ND4DX
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« on: June 27, 2011, 12:28:23 PM »

Ever since I remoted the control head of my FT-7100,  I get reports that I sound off frequency or have sort of a digital sound. I made my own remote cable, it is a 6 foot RJ12, 6P6C straight modular type cable. It has duplicate connectors, cable type, and continuity to the 6 inch cable that directly mounts the head to the radio. I am wondering if perhaps I need to use a shielded type of cable, as I suspect I'm getting RF into the cable when transmitting. Any help with this matter is greatly appreciated.
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K0BG
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« Reply #1 on: June 27, 2011, 01:36:08 PM »

Lots of people do this,and sometimes it works, and sometimes it doesn't. One of the deciding factors is the presents of Common Mode Current. Most of that is a result of incorrect antenna mounting, poor coaxial connections, of mistaking ground for ground plane.

I'm not familiar with the 7100, but most Yaesu remote cables have ferrite beads installed on them, and for good reason.

What is the rest of the install like? Antenna? Mounting style?
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ND4DX
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« Reply #2 on: June 27, 2011, 03:58:25 PM »

The rest of the installation is an Comet SBB5 dual band on a Comet RS730 that is located on the rear lip of  the trunk lid of a Nissan 350Z Roadster. The radio itself is grounded to the vehicle chassis with braid. I use the cigar/accessory outlet with a short 12AWG cable which has ferrite beads, the accessory outlet has never been an issue before as long as I don't use high power. ND4DX
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M6GOM
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« Reply #3 on: June 28, 2011, 02:21:51 AM »

So its not actually grounded then as the braid will be too long. On VHF it needs to be an extremely short run.

I've only ever had common mode issues once - when using a triple magmount with a Little Tarheel on 80m band. I have since learned that lesson and have mounts on the car installed by holes drilled in the roof. No common mode issues anymore.
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K0BG
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« Reply #4 on: June 28, 2011, 06:35:35 AM »

Yes it is no doubt common mode. Part of the problem is the clip mount itself. You might put it on another vehicle, and be fine with common mode. You can bone up on why it is there, by visiting my web site, and read the common mode article. Might want to read the wiring article too.

Everyone seemingly grounds their radio to the chassis. It is not necessary to do so, and in fact can cause a problem to occur, rather than solve one. Further, no matter what power level you run, powering any amateur radio gear via the accessary socket is asking for trouble. Just because you haven't had any problems, doesn't mean you won't!

As Conor stated, drilling holes will eliminate 75% of the problems most mobile installs exhibit. Proper wiring will fix most of the rest.
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