Gmrs ch 18 n o i s e‼️

I have a Midland MXT 275 in a vehicle that is excellent. I have used the scan feature in the past with no problems. Sometime before Christmas, 2022, noise would occasionally trip the squelch. Now the problem has gotten MUCH worse. Increasing the squelch, mostly eliminates the problem, BUT it also blocks most transmissions. I have tried ALL the Midland antennas, from their 6db one, to their others, with no change.

I also have an MXT400 & 500 as base station radios. They don’t have the problem at the house, but all utility power lines, are underground!
Driving around town, I’m wondering if the utility company may have a fault that is causing this interference, but ONLY on GMRS ch 18?
Any thoughts or comments are most welcome.

What kind of a noise is it? Can you record a short segment of it and post it here so we can try to identify it?
You mentioned that the two Midland radios at your house don’t experience noise but a different radio in your vehicle does. Have you tried taking the MXT275 into the house and trying it there for awhile? Or perhaps switched it out with the MXT400 or MXT500 and placing one of those radios in your vehicle temporarily to find out if the noise is eliminated?

Does the signal come and go as you move or is it solid and is it affected by your car radio or when you turn the car on and off? This might sound like a stupid question but do you ever listen to an FM radio station on 104.9?

I’ll rig up a temporary power cord for the 400 & 500 so I can plug it into a 12 volt outlet in the vehicle. What’s interesting about this issue, it started in the 4th quarter of 2022 and only occurred occasionally. However, as each week went by, the noise would trip the squelch more frequently. Now it trips the squelch, EVERY time I start a scan. I will record it as soon as I can, and post.
I’m hoping the problem is not the MXT275 itself. I’ll also have to see if the radio is still in warranty.

I only listen to SiriusXM that’s built into the vehicle’s infotainment system. I will bring the radio into the house and connect it, just to see if the trouble “follows” the radio, and will report back. Thanks for your comments. WRQE346

Given that the channel spacing is so narrow, it is highly unlikely to be a problem with your radio itself.

A higher probability exists that you have external interference of some kind. It’s possible that some other station is emitting a carrier on that frequency.

Do you have a cheap alternative frs/gmrs ht that you can use to replicate the results?

The ourpose of this troubleshooting step is not so much to find out if the radio has an issue, although it does help determine this as well. It is also to confirm whether it is something extraneous or localized to the vehicle itself.

How old are your spark plug wires? You can purchase a tester that you can move along the wires to see if you are experiencing leakage of the wires. Tester is not expensive.

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Finally had some time today to do some testing. Moved the Midland MXT400 and then the 500 from my base station in the house to the vehicle. Heard the exact same buzzing interference on channel 18 on both radios❗️So that clears my MXT275, which is the newest of the 3 radios from having a trouble.
I do have a pair of Midland GXT, X-TRA TALK hand held radios. I think they were the best at the time I bought them. Glad you suggested that👍
This vehicle has less than 35K miles on it, so I doubt spark plug wires will be the culprit but I will definitely check them out.
I think Rick suggested that I upload the audio which I will do as soon as I have some free time.
Thanks to everyone for their suggestions. I really do appreciate it.

The latest update on this continuous noise problem always on GMRS ch 18. It’s NOT a spark plug wiring issue. The noise is there whether the vehicle engine is running or not!
I also hear it on my Midland walkie-talkies. GXT X-TRA TALK. I never hear the noise on my base station radios, the MXT400 or the MXT500.
To be continued…

This noise/interference seems to created by some electronics within the vehicle. Since it’s now always there whether the engine is running or not, I will investigate further as time permits. WRQE346