I would like to share my experiences with the process of reducing EMI and other noises with my mobile installation.
I have an ICOM 706MKIIG installed in my 2005 Mercedes E320 CDI Diesel with the control head in the opening of the front ashtray and the transceiver in the trunk on the rear left.
Not wanting to drill a hole for a mount and with no trailer hitch package readily available I found the perfect spot.
The new Mercedes cars come with a "Tow Hook" in the tool bag supplied which inserts behind a small door in the bumper on the right. In fact the towhook screws in about 8 revolution into the frame and is very sturdy. I had a stainless steel L-bracket made which holds the ball mount and is screwed on to the tow hook. I am sure most folks do not know about that feature unless they study their tool kit. It takes me just 2 minutes to remove it and the car looks right out of the factory.
The probles started when I turned on the engine and wanted to make contacts. I heard ignition noise (although this is a diesel), whistling, whining and other indiscript noises. Only S9 signals would get thru. Man this was a great disappointment. After studying a number of web sites (very helpful was www.k0bg.com
), reading up on the ARRL site and calling Mercedes USA (the latter who were of no help whatsoever) I attacked the problem front to rear.
A grounding strap from the hood to the body in front, a grounding strap from the rig to the body in the trunk,
a grounding strap from where the two exhaust pipes get supported just before the mufflers to the body, a grounding strap from the body to the frame (the body sits isolated on rubber cushions by the way) near the mufflers, and a grounding strap from the right tail pipe to the body and the antenna mount and one from the left tail pipe to the body..
The result: From S9 noise to S1 or less!!! It is a pleasure now to work mobile.
By the way I am using a manual screwdriver antenna from Superantennas that has served me well on may DXpeditions to South America and the Caribbean and maritime mobile operations.
If anyone needs more info get in touch!