Batboard

I have been trying to eliminate electrical interference in an install, and can't seem to find the problem. I installed a model T43KMA7JA9AK Spectra in a 2000 Dodge Caravan and I have been getting an annoying amount of interference. At first it was not all that bad, but it just keeps getting worse.

Everything is wired correctly as I can tell. Appropriate gauge wire directly off the battery for power, and grounded to the floor pan as the Auto owners manual recommends. As for the Antenna I have a quarter wave mounted on a magnet mount. SWR is about 1.2, with reflected power of about 1 Watt. I don't think the antenna is the problem with these kinds of meter readings, but when I remove the antenna the interference goes away. I had to use a SO-239 to mini UHF adapter to connect the antenna, so I thought maybe the adapter was the problem so I swapped it out and still the same thing. The other thing I tried is using a piece of 8 Gauge wire to run from the Antenna lead to the radio connection. When I insert the wire into the radio the noise comes back, but when I touch the Antenna to it, the noise disappears. I am at my wits end with this. I am starting to lean towards something being wrong internally in the radio, but don't have the ability to service the radio myself. Any suggestions what to try, or where the problem could be?

have you tried moving the van to make sure it's not local interference?

Oh yeah. It is when the van is running primarily, but as of lately it also exists when the van is off. It was not doing it before when it was off, but now it is. It does it when I am going down the road, local in town or going out of town as well.

that sounds weird. maybe front-end overload or rectification on the audio output...