MXT115 Transmission Clarity

I have (4) GXT1000 handhelds and (3) MXT115 mobile units we use in our group when off-roading. Anyone talking on the GXT1000 can be heard and understood very clearly, but anyone transmitting in the MXT115 radios sound horrible. Very hard to understand. Sounds as if they’re talking too close to the mic, but they aren’t. It’s getting to where no one wants to use the mobile units, which blows my mind. Anyone else having that issue?

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Get this resolved?? I experienced similar symptoms you describe… broadcasting from my mxt115 one of the gxt1000 users could hear me fine however three others said I either they couldn’t understand me, I sounded like I was in a box, or was just too low if volume. So the closest gxt1000 user who heard me fine would relay my messages to the other gxt1000 users

Sounds like a bandwidth mismatch. Make sure the bandwidth is set the same on all radios.

No, no resolution.
Not sure what you mean by bandwidth. If you mean the precise frequencies, yes they are all perfectly matched.

jwilkers meant bandwidth as in having the right narrow band setting in radio settings.

So if you were using a channelization of x channels, 12.5Khz apart, you set your radio to 12.5Khz bandwidth mode, which will also set the deviation your analogue FM (or DV in digtal modes) modulated carrier uses. This is commonly a few khz narrower through to half the spacing in Khz of the channel spacing. To ensure you also are heard properly, you must be correctly on frequency (the frequency you key in or dial in on VFO controlled set is the centre frequency, likewise it’s the centre frequency used in pre-programmed or manually programmed channel presets.

If you want a demo of this, tune in a regular FM broadcast receiver to a station and slowly manual tune away, at some point before you lose the audio you’ll hear the audio go distorted, which is what others hear on FM transceivers if you are off-frequency (assuming you were using the right B/W to start with).

It also, that distorted effect for being off frequency (where it is the case) also sounds like what you hear on an adjacent frequency a nearby frequency is used by someone who’s over deviating on an FM transmission.

For reference - just because your radio frequency per channel is on sync with the other stations, doesn’t necessarily mean you and they are actually on the right exact centre frequency for the channel as set out in rules. It just means you are all nominally within a few Hz of each other. You can’t conclude you are spot on frequency with knowledge that the right frequencies are programmed in, you need proper test kit (a solid calibrated frequency counter and test tones) to be certain of that.

I would outline how you could properly test the audio in, and check you’re not causing clipping (a major cause of audio distortion if being off-frequency is not the problem, or a poorly adjusted mic gain being too high) - but i’ve already detailed a lot of that elsewhere in the forum, and don’t intend to retype it again.

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So… interesting turn of events for me. I tested and retested. All radios on the same frequencies, no codes or groups. The handhelds were great, the mxt got to where it couldn’t be heard on the handhelds just 50’ away and when you could hear the sound was low. So I contacted Midland via their customer support email and explained the situation, provided proof of purchase, serial number, etc. I’m summarizing their response: It sounds like there is an internal issue in the MXT115… may we send you a replacement. And they did. Going to test it this week.

I have the GXT1000s and received an MXT115 for Christmas. I ended up returning the MXT115. The sound quality was horrible and for the price they charge very disappointing! People complained about low volume on every radio check and transmission. For mobile I spent 50 more dollars and us a BTech 50 watt on medium power and the features and quality well worth every penny. FWIW I believe the GTX1000 has wideband and the MXT115 is narrowband only.

I guess I assumed since both were made by Midland, both indicate in their provided booklets that the channel assignments are on the same frequencies, that they would talk to each other without issue. In fact, when we are sitting still in our UTV they sound PERFECT. I think what is happening is when we are driving, the microphone is picking up the engine noise. The handhelds do not pick that engine noise up, but the mobile does. I assume the mobile has a much more sensitive or higher quality mic to cause that?