This applies exactly as well to the MD-UV390, RT3S, the GPS variants, etc, as they are all the same radio. Is this advice for you, or reminders for me? Hard to tell sometimes.
- Hot air, for desoldering, or good quality desoldering tweezers.
- Stereo microscope (!! very important !!)
- finest tip for your iron you can find
- no caffeine, good nights rest, an hour after eating (otherwise your hands will shake a lot more)
- antenna washer removal tool
Taking it apart
Buy that $15 antenna washer removal tool. It’s worth it if you are impatient.
Otherwise, use a pair of pliers (with some heat shrink or tape on the tips if you don’t want to scratch things up).
Make sure you don’t blow parts away, but hot air makes removing components MUCH easier than trying to do it with a regular iron.
Under magnification, and at this size, your hands are going to shake. Resting your hands or the tools themselves will help decrease the shaking, but what you eat and drink has a huge effect on how much your hands shake at this level.
In general, be well rested, watered, and fed - without caffeine. As you get older it’ll get harder, too, but I don’t have any advice for that other than try not to get old - and if you figure that one out, let me know.
Solder the connections from hardest to easiest. It’s way less frustrating, and quite a bit faster!
Use hot glue to keep wires in place after you’ve carefully inspected the solder joint and verified there are no bridges. You need only the slightest bit. You can use your soldering iron juuuust above the hot glue to melt the glue in exactly the right place. I usually clip a tiny tiny corner off and put it in place with tweezers.
Especially do this to keep wires out of the way of the case screws, lest you accidentally cut a wire when reassembling the case.
Be warned - the glue might be optically clear and it has a high refractive index. This can easily fool you into thinking the connection is on the wrong pin, has broken, or other problems - so convince yourself everything is fine before potting any connections. I’ve needlessly undone several perfectly good connections because of this effect.
For the love of God don’t forget to resolder the antenna connector.
MD-380s (single band!) may be off frequency. Known bug, it’s being worked on. MD-UV380s are generally quite good and I haven’t had any issues over several dozen radios.
Each radio should transmit and receive M17, as verified by another successfully modded radio.
In the absence of that, you can follow the HackRF guide on this blog for copy-paste command lines to receive, and a gnuradio flowgraph to transmit test audio. But it’s much much much easier to just have two radios.
The mods allow for OpenRTX to decode M17, and to sample the microphone - so if you hear your voice on another modded radio, you know that the microphone mod on the transmitter is good and the baseband rx mod on the receiver is good. Switch the radios, and if both still work then you know both mods are good on both radios.
As of 2022 11 05 the rx audio is still quite quiet. Your mod is fine, it’s a software thing and being worked on.