When Towing Honda CR-V Behind Motor Home and Running Lights On, it Interferes with Ham Radio

Question:

I have a 2014 Tiffin motohrome and am towing a Honda CRV 2007. My invisibrake system was installed by CampingWorld. I have a ham radio 2-meter, VHF in the motorhome. When I am not towing, the radio receives perfectly. When Im towing the CRV, I have a problem with reception when I turn the motorhomes headlights on. With headlights off, there is no problem. I recall my installer telling me to drive the motorhome with my headlights on because it would keep me from draining down the battery in the CRV. But when I do, something interfere with the ham radios reception. I believe when I turn the headlights on, Im powering up something in the CRV that is causing the interference. Any ideas what this might be? Oh, one more twist. The interference doesnt start immediately when I turn my headlights on, it starts 7 seconds AFTER I turn them on. Interference goes away immediately when I turn them off. Wonder if theres some way to prevent the MH from sending power to the CRV when I turn the MHs headlights on? Thanks.

asked by: Bob

Expert Reply:

It sounds like the CR-V has a battery isolator installed that is tied into the running light circuit on the RV. This provides power and charge to the CR-V battery so it isn't dead when you go to drive it.

The running light circuit on the motor home has to be connected to the lights on the CR-V but it doesn't have to be connected to a battery isolator. You could instead run the isolator input wire with its own separate connection from the CR-V to the motor home battery via a 40 amp circuit breaker # PK54540.

But that means that you have one more connection that you have to plug in and unplug every time. You could use quick connects # BDW20047, normally for winches, for this, and use some 10 gauge wire # 10-1-1 and # BDW20160. This wire is sold in increments of 1 foot so if you needed 30 feet you would put 30 in the quantity box.

The delay in the interference is not uncommon. First it can take some time for electricity to travel depending on the systems it has to travel through and the resistance and also, depending on the radio, its warm up time could account for the delay.