PLEASE NOTE: all network and talkgroup settings are subject to change in the near future, so please do not waste time setting up for using the BM network with PTT groups on either timeslot. Mostly likely final configuration is 310328 on one timeslot and 8802 on the other, full time, with no PTT groups.
I bought this repeater from W4VSP Al Crane in early 2020. The base radio is a kenwood KSG-4500 UHF repeater. Al had already done all the work of setting up a raspberry pi with ZUM MMDVM modem v0.9, pi-star software, and tuning and setting the audio levels before I bought it.
The original power supply was long gone, and the replacement didn't quite fit within the chassis, causing the lid to bow up a bit. Mostly this was a cosmetic issue, but I wanted to replace it with something that fit better, so I got an industrial switching power supply capable of 30A, and fitted that within the repeater.
While replacing the power supply, I decided I wanted to see if I could mount the entire raspberry pi setup inside the repeater and also power it from the 12V supply. I found the
MoPi 2 hot swap power module which would handle the power needs, and also allow me to add a battery backup so the Pi would keep running during a power outage, and shut down gracefully once the battery got too low.
I discovered that stacking the MoPi 2 with the MMDVM board wasn't practical, so I did some research, and discovered the
pHAT Stack board that would let you put 3 Pi HATs or 5 Pi Zero form factor HATs on a single board, connected to the Pi via a ribbon cable. Mounting the MoPi 2 and the MMDVM board to the pHAT Stack was trivial, but I did not like the ribbon cable mounting options, and I was concerned about the airflow with the ribbon cable. The solution was to replace the Pi with a Pi Zero W, soldering in an extra tall header with female connector on the bottom and male on the top, so it could fit directly onto the pHAT Stack. Of course, the Pi Zero W does not have ethernet, and wifi from inside a metal cabinet would be a joke, so I added a Pi Zero form factor hat on top that included a 3 port USB 2 hub, and a 10/100M ethernet port.
For battery backup, I chose an inexpensive 6 amp-hour LiFePo battery from amazon, which is about the same form factor as a small gel cell battery for an alarm panel.
After several weeks of trying various ways of putting together the jigsaw pieces, it all finally came together April 27, 2020. I added a bulkhead mount ethernet passthrough to the back panel, and ran shielded twisted pair to the ethernet port. I pulled the external control port back inside the case, and made a shorter cable to interface it to the MMDVM board. Everything is now mounted, tested, and back on the air as of the morning of April 28, 2020.