radio noise in truck stereo

[2009KVFD976]

I have a pm400 vhf that was in my 01 explorer and it was used with no probs for about 4 yrs. I put the radio in my 01 Silverado and when I key the mic, I get a loud popping humming sound through my sound system that I never had in the explorer. the antenna is mounted on the roof via nmo hole mount, radio is mounted on my headliner console, grounded about 12" from it, power cable is spliced into my 4ga amp wire (maybe the prob?) that comes straight from the battery. what do yall think if I run my power cable to the radio directly from the battery or another good 12v power source? thanks for any help in advance!!

 

[jim202]

As we see all sorts of new electronics being jammed into the newer vehicles, the RF suppression is getting less due to cost. You can try going to the effort of changing your power feed, but my bet is it won't change anything.

I would look at how close the radio antenna is to your mobile antenna is. What type of coax cable you used between the radio and the antenna.

Another big problem with the newer two way radios is that they are using more plastic cases. Have seen cases where the radio mounted above a siren in a fire truck caused problems with the siren. The radio uses a plastic case. Sometimes adding a metal plate between the 2 units reduced the problem. In other cases, the siren or radio had to be moved further apart from each other. It may even take a combination of things to reduce the problem to a point you can live with.

You can try different frequencies, but I think you will find it doesn't matter.

 

[SteveC0625]

I have a pm400 vhf that was in my 01 explorer and it was used with no probs for about 4 yrs. I put the radio in my 01 Silverado and when I key the mic, I get a loud popping humming sound through my sound system that I never had in the explorer. the antenna is mounted on the roof via nmo hole mount, radio is mounted on my headliner console, grounded about 12" from it, power cable is spliced into my 4ga amp wire (maybe the prob?) that comes straight from the battery. what do yall think if I run my power cable to the radio directly from the battery or another good 12v power source? thanks for any help in advance!!

The Motorola install manuals all specify that the hot lead should be direct to the battery. They also want you to run the ground lead to the area of the battery and then connect to a good factory ground there; NOT the negative post of the battery. Tapping your 4 ga power line will work fine electrically, but may be a conduit for rf interference. When I do an install, I try to route the hot and ground of the power cables away from other bundles of vehicle wiring.

Double check all of your grounds in your install, too.

 

[cmdrwill]

YES run the radio's positive power lead directly to the battery buss. The buss that feeds the high power fuses. Ground should be near battery ground.

 

[mmckenna]

what do yall think if I run my power cable to the radio directly from the battery or another good 12v power source? thanks for any help in advance!!

There is no "other" good source of 12 volt power. Run the power for the radio directly from the battery. Tapping into other circuits is an excellent way of causing interference. While it may not be the cause of your issue, it certainly isn't helping.

 

[Mikem001]

Check the ground or try changing the ground location had a similar problem that I would hear it in the subwoofer in my car and grounding it in a new location fixed the issue.