RF issues with mobile installation

**WB5ZDD** · Tue 30th Nov 2010, 20:03

I have a 1998 Jeep Cherokee.

I have an ICOM 706 radio feeding a ICOM AH4 auto tuner, and in turn that is feeding a 102" whip, 6" spring and ball mount.

I understand the 102" whip isn't the ideal antenna, however I was more interested in spending my time on the radio instead of putting together and taking apart the antenna as I entered garage or parking garage.

This configuration worked VERY well with mild tuning issue on 17 meters until....

I LIFTED THE JEEP 7"

Now I can still tune the antenna however when I transmit I can stop the engine from running, and I mean driving down the road at 40 mph. From the "CHECK ENGINE" OBDII scanner reading apparently it's getting into the CPS (Crankshaft Position Sensor).

I have the power connection for the 706 running directly to the battery, both positive and negative. The antenna tuner is about 5 inches from the connection on the ball mount.

{continued next post...}

**5B4AJB** · Wed 1st Dec 2010, 21:55

Try re-bonding the engine/gearbox to the bodywork in several places, their earth connection has been compromised and are resonating 8D

**WB5ZDD** · Thu 28th Apr 2011, 16:53

Originally Posted by m0bov

Move the rig and tuner to the boot, make sure the cable from the mount to the tuner is as short as possible. Put a few turns in the feeder to the tuner and earth the tuner and rig to the same point. I would also put a ferrite ring or two on each of the power leads and the head unit. I also use a clip on choke on each end of the mike cable and any speaker cables.

Boot? Sorry for the delayed response. I don't think I have it set to receive e-mail notifications of post replies.

**G6NHU** · Thu 28th Apr 2011, 19:03

The boot is the correct term for what our American cousins call the trunk

**WB5ZDD** · Thu 28th Apr 2011, 19:13

Originally Posted by G6NHU

The boot is the correct term for what our American cousins call the trunk

Well I'm half way there...

**AE6ZW** · Mon 6th Jun 2011, 19:18

I have placed many clip on RFI choke / EMI filter, on coax cable, power cable of radio, anything else you can think of, it usually fix type of the problem described , in the passed for me. I put on telephone wire, computer cable, etc, it also reduce amount of RF noise coming from some wire in the car.
I got mine from ebay 100 for about US $50