There are two trim pots inside the 115. I suspect that one might be the deviation, but it's am too chicken to try it. If I got it off frequency, I would be sunk. There is absolutely no information that I can find on these radios.
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GMRS Midland MXT115
- Thread starter Shadetree Mechanic
- Start date
You know, the Midland looks a lot like the Retevis RT98 (and Anytone Smart CB)... but the Midland has a USB port.
Any chance you can post a pic of the circuit board?
Wow...
Way different then the Anytone Smart C, but it is the same form factor...
My bet would be the 2 settings on the Midland are FM Power and Deviation...
And I'll bet Deviation is the lower left one (like the Anytone Smart)
Measure where the pots are currently set, tweak them and watch on a O'scope for a power change... if nothing changes, put them back where they was...
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Ok, then if I were to mark the pots, is there any hope that I could put them back to where they belong if it doesn't work? I don't think my power meter will do that high of a frequency? It is an Autek WM1. I have an o scope, that would probably do it. But could it measure deviation?Wow...
Way different then the Anytone Smart C, but it is the same form factor...
My bet would be the 2 settings on the Midland are FM Power and Deviation...
And I'll bet Deviation is the lower left one (like the Anytone Smart)
Well, the Scope wont do deviation, but you could tell if one pot is for power, and then the other would be for Deviation...
Mark them, but also try to read the value they are set at with a meter, that way you can set them back.
Another way to "check" deviation is with a monitor radio, as you increase the deviation, your audio will get louder... but there isn't a way to know how wide you are getting.
If you have an SDR....
https://www.rtl-sdr.com/measuring-frequency-deviation-fm-transmitter-rtl-sdr/
Here is another SDR link:
https://www.qsl.net/kp4md/freqdev.htm
I did this with my Anytone CB... it works
I would love to get a real FM Deviation meter... but the price on those is pretty stupid
the Autek Research WM1 is only rated to 30Mhz, I don't think I'd try it up at 462Mhz
Mark them, but also try to read the value they are set at with a meter, that way you can set them back.
Another way to "check" deviation is with a monitor radio, as you increase the deviation, your audio will get louder... but there isn't a way to know how wide you are getting.
If you have an SDR....
https://www.rtl-sdr.com/measuring-frequency-deviation-fm-transmitter-rtl-sdr/
Here is another SDR link:
https://www.qsl.net/kp4md/freqdev.htm
I did this with my Anytone CB... it works
I would love to get a real FM Deviation meter... but the price on those is pretty stupid
the Autek Research WM1 is only rated to 30Mhz, I don't think I'd try it up at 462Mhz
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I have a Nedsr, why didn't I think of that. I use it sometimes without an antenna to record my transmit audio to adjust my rack gear. I will have to give it a try.
https://www.nooelec.com/store/sdr/sdr-receivers/smart.html
Years ago some ham radio shops that sold and repaired radios placed a deviation meter in their store window. Spectronics in Oak Park, ILL was one such store. Even after the store closed the meter was left on so mobiles could drive up and make adjustments. I used that service several times. Of course that doesn’t help your situation now. Without being software programmed or having a meter, most are playing it by ear nowadays by listening to their audio on another radio, particularly the audio on the output of their repeater. Some repeater inputs are more selective than others, but at least those users will know if they’re hitting one too softly or too hard by asking listeners. To achieve their final desired result, besides adjusting deviation, guys on our local repeaters are always experimenting with different mics, and playing with distance from them.
I turned those pots on my MXT-115. The lower left pot adjusts frequency. The upper one might be deviation, but I could not see or hear much difference. I don’t have a deviation meter so I can’t say for sure. No change to power output, so it’s not that. It could possibly be a deviation adjustment for the PL tones ???
The MXT-275 only has one adjustment pot, and that only adjusts frequency. The deviation on those models is even lower than the MXT-115. Again, fine if you are talking to other narrow band radios, but too quiet when when working through a wide band repeater. These radios are really targeted to the offroader crowd, so I need to unload these micromobiles. Any one interested in some cheap Midland mobiles ?
In any case, I found an Anytone AT-779UV which is Part 95E certified in the U.S. for GMRS. It is about the same overall size as the Midland micro mobile, but it can be set for wide or narrow band audio. You have to use the software to change the deviation and PL/DCS tones (encode/decode), and there is another piece of software for the radio on Anytone’s site that changes the operating frequencies for different parts of the world, but I am seeing 20 watts out on high power from the Anytone AT-779UV on GMRS, and looks like it will be a nice alternative to the Midland rigs. And less $$$ than the Midlands.
http://anytone.net/pro_info100.html
The MXT-275 only has one adjustment pot, and that only adjusts frequency. The deviation on those models is even lower than the MXT-115. Again, fine if you are talking to other narrow band radios, but too quiet when when working through a wide band repeater. These radios are really targeted to the offroader crowd, so I need to unload these micromobiles. Any one interested in some cheap Midland mobiles ?
In any case, I found an Anytone AT-779UV which is Part 95E certified in the U.S. for GMRS. It is about the same overall size as the Midland micro mobile, but it can be set for wide or narrow band audio. You have to use the software to change the deviation and PL/DCS tones (encode/decode), and there is another piece of software for the radio on Anytone’s site that changes the operating frequencies for different parts of the world, but I am seeing 20 watts out on high power from the Anytone AT-779UV on GMRS, and looks like it will be a nice alternative to the Midland rigs. And less $$$ than the Midlands.
http://anytone.net/pro_info100.html