Interference from my truck affecting my hand held radio

[Guest Zach]

I just got my first GMRS radio a few days ago and I haven’t had much chance to use it. Something I noticed pretty quickly on my Radioddity GM-30 was channels 8, 21, and 22 have random interference think pulsing static. I get the same thing on RPT 8 and DIY 7 at first I thought it had something to with the damn for the lake in this little town but then I found parking spot while the radio was doing this and the radio just stopped making the noise and went back to scanning through the channels till I started the truck back up. Does anyone have any idea why my truck would affect it like that

[BoxCar]

Ignition noise

[wayoverthere]

LED running lights? wireless charging pad perhaps?  Both are also possibilities.

[AdmiralCochrane]

Does the truck have a built in 120v output inverter?  That's another possiblity 

[SteveShannon]

As others alluded there are many possibilities ranging from wiring (ignition noise, alternator noise) on your truck to accessories (LED lights, AC inverter,) to aftermarket high energy lights. Plus some radios seem to be more sensitive to such noise. Running power and ground all the way to the battery could help immensely but might not. You’ll just have to try different things until you figure it out. Does the noise change pitch when the engine RPM changes? Then it’s probably either ignition or alternator. 
Does it worsen with rough roads?  It might be a loose connection somewhere. 
There are ferrite filters that might help. I don’t know much about them but I suspect a Google query would result in inundation.

Good luck tracking it down. Please let us know what you find. 

[Guest Zach]

2 hours ago, Sshannon said:

As others alluded there are many possibilities ranging from wiring (ignition noise, alternator noise) on your truck to accessories (LED lights, AC inverter,) to aftermarket high energy lights. Plus some radios seem to be more sensitive to such noise. Running power and ground all the way to the battery could help immensely but might not. You’ll just have to try different things until you figure it out. Does the noise change pitch when the engine RPM changes? Then it’s probably either ignition or alternator. 
Does it worsen with rough roads?  It might be a loose connection somewhere. 
There are ferrite filters that might help. I don’t know much about them but I suspect a Google query would result in inundation.

Good luck tracking it down. Please let us know what you find. 

That’s the interesting thing this is a hand held unit with its own battery power. The truck is a stock 88 Chevy so there’s really not much that runs on it that I can think of to cause interference. As far as when it does it it seems random 

[Lscott]

You can try removing the antenna from the radio and see if the noise is still present. This will reduce the sensitivity of the radio a lot so the noise source will have to be very close to it.  If not then hold the radio up close to the dashboard while moving it around and see if it picks up the noise. You can also try it around the exterior of the truck too. If you pick it up chances are the source is very close to the radio.

[SteveShannon]

6 hours ago, Guest Zach said:

That’s the interesting thing this is a hand held unit with its own battery power. The truck is a stock 88 Chevy so there’s really not much that runs on it that I can think of to cause interference. As far as when it does it it seems random 

@Lscotthas a great idea for tracking the source. 
Keep in mind that every spark plug is a spark gap, the earliest form of radio transmitter. There’s usually some RFI reduction in spark plug wires but if your plug wires are going bad or if you replaced them with cheap substitutes you may have an issue. 

[wayoverthere]

1 hour ago, Sshannon said:

@Lscotthas a great idea for tracking the source. 
Keep in mind that every spark plug is a spark gap, the earliest form of radio transmitter. There’s usually some RFI reduction in spark plug wires but if your plug wires are going bad or if you replaced them with cheap substitutes you may have an issue. 

I was thinking that direction too...is that year still distributor and plug wires, or had they gone coil on plug?  if it's individual wires and a distributor, i might try pulling them off at the distributor one at a time, and see if the noise stops with a specific one. if so, bad plug wire.  if there's no change, you've at least ruled out a short in one or two being the issue; while it doesn't completely rule out ALL of the wires being a source of interference, the intermittent nature seems to point more toward a bad connection SOMEWHERE than a consistent source.