CB w/amp bleads through truck speakers when the truck is running

[Lkaskel]

Hi Everyone,

I had a few amps come across the desk this week and I thought I would try one in my truck as I don't run one regularly. I connected a Pride 150 up to my Tram D62 and all of that is connected to a Wilson 5000 mag mount. When running the radio with the amp on it came through the truck speakers. It kind of acted like talkback. This does not happen if the amp is not on. As a note, the truck is an 07 F150 and the radio is an aftermarket Jensen Android Auto model. This happens even if the radio is switched off but the truck is still running. The only way it does not happen is if the truck is off and the power to the truck radio is off. Has anyone had a similar experience with their mobile setup? I doubt I will put one in the truck permanently but it would be nice to understand why this happens and if there is anything I could do about it.

Thanks as always!!!

 

[9C1Driver]

RF can do funny things like that. There are many variables involved. Clipped radio, poor ground, bad jumper, bad coax, class C amp, location of antenna, location of coax run, and in some cases it will never go away.

Years ago a tow truck driver could key his radio and amp and his wipers would turn on. A local security guard would key up and the yellow strobes in his light bar would light up.

 

[BC Coyote]

It's because the speaker wires are unshielded and are acting as a crude antenna picking up the amplified RF from the linear. Bypass caps at the speaker terminals will help and maybe even eliminate the problem.

edit to add: You could also try chokes on the speaker leads.

 

[Lkaskel]

Thank you both for your thoughts!!! The logic challenge I have is that the talkback effect only happens when the truck radio has power (even if its turned off). The only time this does not happen is when the truck is turned off and therefor no power to the radio. I am expecting that because the radio is an upgraded one (vs the factory one) that may come into play. Of course, I have no idea I wil ltry a different radio, jumper cables and such as a test. Those are very good ideas!!!

 

[Shadetree Mechanic]

There might be an amplifier on your radio from the factory. I would think it would turn on and off with the radio, but maybe not.

 

[FlatlandBusa]

Make sure everything is grounded, then if it still bleeds through put some quality (not Amazon) ferrite on the speaker and power wires just before the radio. Should be an easy fix.