I enabled DMR last week and spent some time configuring it. This week I had to set the DMR transmit deviation in order to get it to work.
Essentially setting the TX deviation for DMR is the same as how I set the transmit deviation for DSTAR in the beginning. I used a service monitor and checked the deviation level while the repeater was transmitting. It was lower than it should have been, so I increased the level in the expert MMDVMHost editor on the line that said DMR Level. This adjusted the deviation for just DMR, leaving the deviation alone for all other modes.
I also created a box/case for my project out of a large crayon box that I found at WalMart for about $3.
- I used a template for the Pi to drill four holes in this box for some #4 screws to mount the Pi and MMDVM duplex. I also put a piece of acrylic between the Pi and this case so that it wouldn’t be pressing against the back of the Pi.
- I then cut out a hole for the size of my 3.2in Nextion Display.
- I also drilled holes around the display cutout to mount the display in place.
- I used plastic from an old ice cream container to create a bezel to go around the display since part of the display doesn’t show anything and is instead used for the touch screen controller/wiring.
- I added two external antenna connectors. I bought two male to female jack/panel mount SMA connector extensions for about $6 each and then I added some right angle SMA connectors (male to female) 5 for about $4.
- For the external antennas I drilled the holes in the box as far apart as I could and installed the female jack connectors through the hole.
- Then I screwed a right angle SMA connector on each jack.
- Next, I used a couple right angle SMA connectors on the MMDVM hotspot/repeater board.
- Finally, I installed all of the electronics.
Here is the finished case.
