Help me eliminate QRM on 2-Meter Radio in Motorhome !!!

[bobmoore1954]

I have QRM on a 2-meter radio in my motorhome that significantly degrades receiver performance.  After much testing, I have narrowed the source down, but don't know how to fix it.

If we're driving the motorhome without our toad, everything is fine.  Radio works great.  No QRM.

If we tow the motorhome (a 2007 Honda CRV with Roadmaster Invisibrake system), I get QRM when I turn the motorhome's head lights on.  With head lights off, no QRM.  With headlights on, I have significantly degraded receive performance.  Now here's the weirdest thing.  The QRM starts 7 seconds after putting the headlights on.  Not immediately, 7 seconds later.  Problem goes away immediately when I turn headlights off.

I pulled the fuse on the CRV's navigation system/radio thinking the QRM could be related to its GPS finding the sat's, but that didn't help.

Any ideas, please.

 

[Jim Godward]

What kind of Headlights do you have, regular incandescent, LED or HID.  Both LED and HID are possible candidates for causing interference.

Just a thought,

 

[bobmoore1954]

When the motorhome lights are on but the toad is not hooked up, there is no QRM.  It's only when the MH lights are on and I'm connected to the toad.  Somehow, putting the MH headlights on provides power to the toad to keep from draining down its battery when it's being towed.  I think something in the towed is getting powered up by the MH and that's causing the interference. 

I'll be talking to my installer to pick his brain.

 

[SVTotem]

Is this a new install or has this configuration worked in the past and recently picked up this issue.

The delay may indicate a board component failing when heated up. Is their a diode in the toad wiring hookup?

 

[bobmoore1954]

This is an issue that started with the installation of the towing system.  I'll check with the installer to see if there's a diode in the system. 

 

[racersedge]

This is an issue that started with the installation of the towing system.  I'll check with the installer to see if there's a diode in the system.

take a rg6 or rg59 coax cable and use that as the 12V supply line from source .center core for power and shield cover for ground or run ground and 12V lines directly to your starter battery