poor RX quality when driving

[Tkempt200]

i have 2 MXT275 radios in 2 different trucks when ether truck is driving the RX just all broken up like the mics are in water. doesn't matter the distances but we are most of the time less then a mile from anther. we can go to Retevis NR30's and everything is great. when on the MXT275 i can listen to a repeater when out of town ( there no repeater local to me anyone uses) and i can hear all that traffic fine. ive never tried talking out there so i dont know if this is a TX or RX problem.but when it happens both radios do it. some times its fine.

we do use a CTCSS tone. both have different antenna setups. one is the out of box little mag mount, the other is a MXTA26 on a head act rack. SWR's is both under 1.5. direct wired. not on the sig plug. both trucks are diesel trucks

ive had CBs is just about every truck ive ever owned so these are not my 1st radios. i just dont know what could be causing this being you can hear it from both radios.

[kidphc]

Does it sound ok when sitting still?

Can be a combination of things.
1. crap mics
2. Radios are set to narrow band on the channel (fairly often cause what you describe, being underwater). It will mostly sound like it is undermodulatrd and muffled. Especially, if one radio is set to wideband and the rx radio is set to narrowband.
3. Picket fencing (not likely). The radio signal partially blocked from one radio to another. Sounds like the audio is skipping.

Keep in mind the antennas aren't static. Due to them wagging in the wind (the longer they are the worse they can get) can cause other issues.

But if it is muddled audio between two mobile radios close to each other, might bet is 1 or both radios are set to narrow band. Frs channels are narrow band by default and can't be changed. Verify on both radios are set to wide band on the particular frequency. Use the repeater out put channels and jack the power to mid levels and see if things improve.



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[Tkempt200]

The crap mic thing may be an answer. I bet it’s the air noise of the trucks doing 70mph is technically what we hear. We don’t have the problem sitting still or at lower speeds. I had a ghost antenna to start with the same problem so the antenna moving around in the air is kinda out. Also the MXT275 is a narrow band only radio which doesn’t help. I radio switch may be what I’m looking at. 

[WRQC527]

On 5/16/2024 at 4:58 PM, Tkempt200 said:

i have 2 MXT275 radios in 2 different trucks when ether truck is driving the RX just all broken up like the mics are in water. doesn't matter the distances but we are most of the time less then a mile from anther. we can go to Retevis NR30's and everything is great. when on the MXT275 i can listen to a repeater when out of town ( there no repeater local to me anyone uses) and i can hear all that traffic fine. ive never tried talking out there so i dont know if this is a TX or RX problem.but when it happens both radios do it. some times its fine.

we do use a CTCSS tone. both have different antenna setups. one is the out of box little mag mount, the other is a MXTA26 on a head act rack. SWR's is both under 1.5. direct wired. not on the sig plug. both trucks are diesel trucks

ive had CBs is just about every truck ive ever owned so these are not my 1st radios. i just dont know what could be causing this being you can hear it from both radios.

This is just a guess based on my experience. I had a Juentai JT-6188 (QYT-8900 clone) in my van that sounded fine when I was sitting still, but when moving, even at walking speed, it picked up interference that would break the squelch intermittently. Basically it made the radio unusable as a mobile. I think it was the signal from one or more of the wheel speed sensors overloading the receiver. There was no fix, so I moved it to a go box and used a different (Yaesu) radio. Sometimes there is interference that the radio's filtering simply can't block. 

[WRDJ205]

Are you using the same antenna with the Midlands as you are with the Retevis?  
 

It’s getting warm in La and I’ve noticed a significant squeal when the mic is sitting in the hot truck all day and I turn it on.  Might be temp driven?  

[Tkempt200]

The Retevis are handhelds. So no. Not the same antenna. 

[SteveShannon]

5 hours ago, Tkempt200 said:

The Retevis are handhelds. So no. Not the same antenna. 

Some people use an adapter to use their external antennas with their handhelds when they’re in a vehicle.

Noise on a mobile radio when moving can be caused by vibration exacerbating a poor connection somewhere in the feedline to the antenna or the antenna or mount, or by a bad power or ground connection leading to the radio (as well as other connections).  Try hooking you external antenna up to the handheld and go for a drive.  If the noise occurs then you have reason to suspect the feedline or antenna mount.

Otherwise inspect how you power your radio.  
And maybe the radio itself is just affected by vibration.  While operating stationary try shaking the radio to see if the problem occurs.

Finally, don’t discount picket fencing.

Good luck!

[WRDJ205]

29 minutes ago, Sshannon said:

Noise on a mobile radio when moving can be caused by vibration exacerbating a poor connection somewhere in the feedline to the antenna or the antenna or mount, or by a bad power or ground connection leading to the radio (as well as other connections).  Try hooking you external antenna up to the handheld and go for a drive.  If the noise occurs then you have reason to suspect the feedline or antenna mount.

Much better job of explaining than I could do last night. 

[Socalgmrs]

I’d personally put the midland on eBay and spend the money on a good radio.  Heck we use our $130 water proof radios rolling down dirt roads at 55mph in old trucks with the windows open or on the freeway at 70 with the windows down on the highway and we never have a problem Being heard or hearing.   We don’t even have this problem with cheap hand helds. In the trucks.     It could be a narrow band issue, a ground issue, a radio issue or a mic issue.  But I’m betting it’s a narrow band midland issue.