Headless aprx server trial

aprx01

In the continuing trials of APRS digi+iGate servers, an aprx server running on a RPi.

aprx is a true Linux application, and v2.08 was available as a .deb package (though not part of the Raspbian distribution).

The package installed easily, and configuration was pretty straight forward. Conveniently, all configuration parameters are in one file… a welcome change from the javAPRSSrvr trial.

aprx supports SMACK (a variant of KISS with CRC protection across the serial link to the TNC), so a EPROM was burnt for the Paccomm Tiny-2 Mk-2 with SMACK v1.3 in the upper half. The configuration had no dependence on battery backed memory.

KISS has become the most popular TNC interface protocol for most modern servers, and very few of the support any CRC variant of KISS, so aprx is somewhat of an exception. Though many TNCs claim KISS support, most modern ones are half baked and don’t fully support the KISS command set, much less extensions like SMACK.

A drive test indicated that it is performing properly, the TNC is properly mannered in its access to the channel apparently giving effect to the persistence and slottime parameters.

Performance and reliability will be monitored over the coming weeks.

Installation errors / changes

logrotate did not work properly, needed chmod g-w /var/log/aprx.

I changed log rotation:

/var/log/aprx/aprx-rf.log /var/log/aprx/aprx.logĀ  /var/log/aprx/dprs.logĀ  /var/log/aprx/erlang.log {
daily
rotate 7
compress
missingok
notifempty
create 644 root root
}