Digital Voice Hotspots
WORK IN PROGRESS - COMMENTS AND CORRECTIONS WELCOMED!
My own notes about configuring the MMDVM_HS HAT digital voice hotspot using the excellent Pi-Star software and the radios which go through it. This page is really my own notebook, and therefore a work in progress, but I hope it might eventually be a help for others.
Configuring the Hotspot
You need to program the display's firmware by downloading a file and copying it to FAT32 formatted micro-SD card. Choose your preferred display format and Nextion size and download from the .TFT files here. There are files for the DB2OE, G4KLX and ON7LDS formats. Although the PD0DIB page connects the display to the RPi, I expect that just the +5 supply is required, but perhaps it's better to terminate the data leads anyway. Once the display is powered up with the card inserted, you will see it updating the firmware. You can then power it down and remove the card.
You can connect the display to the MMDVM_HS HAT using the "modem" points. I added in pins so that I could use the wires from the Nextion without cutting off the pre-supplied sockets. Connect 0V and +5 V, and TX to RX reversed (i.e. TX display to RX HAT vice versa).
Using the Admin panel with the Pi-Star, select the display as Nextion, and the port as "Modem" as you are using the "modem" connection on the HAT.
You need to choose a suitable in-band access frequency. Mine was set to 431.075 MHz, although after careful checking I found that 431.0745 was closer to producing the correct output frequency. Nevertheless, 500 Hz at 431 MHz is not a great error (and the device is in an unheated cupboard).
There's a list of reflectors here, which lists REF001C as D-Star's MegaRepeater in London.
Updating and settings for NTP and SNMP
To update the pi-star you use two commands, making the disk writeable before running each. Use PuTTY to log into the RPi from Windows.
rpi-rw sudo pistar-update rpi-rw sudo pistar-upgrade
SNMP and NTP external access
I found that, by default, the security settings didn't allow SNMP or NTP access from devices on the local network. tp fix this, you need to update the iptables:
rpi-rw sudo iptables -I INPUT 3 -s 192.168.0.0/16 -p udp -m udp --dport 123 -j ACCEPT sudo iptables -I INPUT 3 -s 192.168.0.0/16 -p udp -m udp --dport 161 -j ACCEPT rpi-ro
Resetting SNMP temporary files
If you use SNMP "pass" commands, you may find that these stop working once the disk is read-only. To reset that, you can use cron to run a job at e.g. 05:00 every day with the commands:
sudo mount -o remount,rw /dev/mmcblk0p2 / sleep 1 sudo rm -rf /var/lib/snmp/.snmp-exec-cache && sudo ln -s /tmp/.snmp-exec-cache /var/lib/snmp/.snmp-exec-cache sleep 1 sudo mount -o remount,ro /dev/mmcblk0p2 /
Even then, you will get some breaks in the logging - for example.
Programming your radio - examples
D-Star - Icom IC-7100
Programming - it's convenient to program a number of channels:
Having programmed at least the above, you need to first select a reflector channel you programmed, then press the PTT for about half a second. Then go back to the "talking" channel. Your hotspot should remain connected to the chosen reflector. Listen to check that you are on the expected reflector, and when there is a suitable gap call in. To change reflector, first select the programmed Unlink channel, half-second PTT press, select the desired reflector channel, half-second press, then back to the talking channel. It's actually easier to do than described, once you have the hang of it.
This is about the limit of my current knowledge, so comments and corrections are welcome!
DMR - Radioddity GD-77
First, add the new channel, then a new zone (optional), to which the new channel is added.
To select other reflectors, use the Manual Dial function of the radio.
DMR - Retevis RT3
Fusion - Yaesu FT-70DE