Project: POCSAG paging network infrastructure

Like OH2LAK reported on his blog, I've started implementing infrastructure code for an amateur radio paging network. Erik (OH2LAK), Weltto (OH7JEV) and Lasse (OH3HZB) got the POCSAG modem running, interfaced it to a Motorola radio, and configured a couple of pagers to receive it on 144.975 MHz.

I got the bits and pieces yesterday for development and debugging, started working on the server software at 6.30 PM yesterday evening, and now I have a working client-server paging network infrastructure with strong authentication, queuing, and support for multiple transmitters. I grabbed quite a bunch of code from the aprs.fi code base, of course.



The system consists of:

• A server component which receives messages from authenticated message source clients, queues them, and provides them to the transmitter clients
• A client library (Perl module) which is used to communicate with the API of the server
• A transmitter client, which fetches messages from the server using the client library and feeds them to the POCSAG modem (and, optionally, transmits CWID at regular intervals)
• And, for demonstration purposes, a DX cluster client which maintains a connection to a DX cluster server, filters DX spots, and sends them to the paging server using the client library. I think I've made a full circle now, over the past 15 years. Feels like home.

The next thing I'll write is an APRS-IS client to collect APRS messages from the APRS-IS and gateway the to the paging server (for those recipients who have a pager configured on the server).

The server is designed so that it's possible to run multiple instances of it at diverse network locations, so that losing one server will not break the whole network.

The network will probably be national, within Finland, coordinated by RATS (Radio amateur technology society of Finland). The system will be demonstrated at the RATS technology day in Otaniemi, Espoo, 20th of March, 2010 (that's next Saturday). I suppose the code and documentation will be published so that you can set up your own networks.