I have 2006 Chevy Impala LTZ with the center console.  I agree it is a bear to mount something in there but I got it done.  I got a scanner and CB mounted each side of the center console.  Far enough forward so the seat wont hit when it slides forward.  Although I am tall, I rarely slide the seats forward.

I have plans of installing a dual band in the trunk with the detachable face plate under the dash between the door and steering wheel.  

It is also rather challenging to install antennas.  After much trial and errors and debating, I settled with thru-glass antennas.  I know they are not as good as a NMO mount, but drilling holes is strictly forbidden by me.  The antennas work surprisingly well.

I can shoot ya some pictures if ya want.

N9QKG@SBCGLOBAL.NET

I have a NMO mounted on the rear bumper of a Chevy Tahoe.  I take the antenna off for a car wash.  It doesn’t hurt the mount any to leave it exposed and give a good cleaning.  By the time I got through the car wash dryer, and drive a couple mile home, the mount is dried off.  I put the antennas back on when I get home.  No problems.

If I leave the antenna off for a few days for whatever reason, I always cover the mount just to keep the connections clean.  I have just the base of an NMO antenna I use as a raincap/cover.  Trolling thru a hamfest some time ago, I bought a cheap, junk, short NMO antenna.  I bought it specifically for the purpose of an environmental cover.  I cut the stinger off of it even with the top of the mount and deburred the cut.  It works perfectly, and can be thrown in the glovebox.

You mentioned you ran the wireing and coax through the firewall along with a bundle of wireing.  You bypassed that power wire by setting a battery next to the radio.  You mentioned you put a different piece of coax on with a dummy load and the problem was gone.  You did not say if it was the same coax running through the firewall.  I am assumeing it was a different coax run out the door.  I first thought the power wires was bringing something in, but I wonder if the coax is doing it since it runs around and with a bundle of wireing.  Now, you would think the coax shielding would protect from that, but RF is a funny animal.........

Mike:

I have a part time gig as a casual driver.  I get whatever truck is available.  I normally get a 1980 Volvo, but not always.  Anyway, the regular driver normally leaves his childrens band in it for me.  I carry an ample supply of small bungy cords and strap my Yaesu FT 5100 to the top of the dash, or on top of their CB.  I have a vice grip bracket/mount with a 3/8" stud on it. I screw a bottom loaded 2-mtr antenna onto.  If I get a truck that doesnt have vice grip friendly mirrors, I can always find a place to clamp it.  Usually up in the air dam above the sleeper.  If nothing else, clamp to a hand rail.   It works just fine.  Same vice grip type mount the day runners use.  (Yellow, CF, Roadway, etc)

Dave, N9QKG