RFI in LCS850

[WV8VFD]

I have a Signal Vehicle Products LCS850, and a Motorola Astro Spectra 110w VHF radio in my car and a quarter wave. It is a 2001 Civilian Crown Vic.


Whenever I key the radio I am getting RFI into the siren. Running the radio on a mag mount towards the back of the car I am getting just a click when I key up, and a click when I un key.


If I move the mag mount towards the center of the trunk, I am getting beeps from the siren that sound like morse code. Same if I put the antenna on the actual NMO mount drilled in the trunk.


The radio and siren are ran from a 6 gauge wire coming from the battery, and grounded at a ground bolt on the trunk. No coax and power run anywhere near each other.


The SWR on the antenna is 1.2-1.3:1


I have put ferrite chokes on the power and ground to the radio and siren, and on the control cable for the siren, and it didn't help any. Only thing I haven't done is ground the trunk lid yet.


This is driving me insane. I have put a whelen 295SL100 in, and it works fine. I am about to just break down and get a HHS2200 if I can't figure this out.


Any help would be appreciated.


Thanks