Radio Group/Pager

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Revision as of 23:31, 20 April 2024 by Asj (talk | contribs)
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MB7PNH

We will soon have a pager transmitter running from within the hackspace. It'll be a small USB powered box, probably stuck to a window with suction cups. The station has been allocated the callsign MB7PNH (Pager Nottingham Hackspace), and is built using an Adafruit Feather LoRa board, which has an RFM69 module. There are more details about this, and the PCB, on Aaron's website

MQTT Topics

Transmission of pager messages using MB7PNH without an amateur radio license is against the law - these topics are not listed on MQTT Topics or use the nh/ topic prefix for that reason You must have an amateur radio license to transmit messages via this node. These topics are available via jarvis.

POCSAG MQTT Topics
Topic Description
pocsag/send Sends a pager message to a specific RIC. RIC and message are separated with a pipe symbol e.g. "300424|Hello Aaron!"
pocsag/power Taking a value of either "ON" or "OFF" - this can be used to power down the transmitter if there is an issue (this is a requirement for unattended nodes).
pocsag/status Sending an empty message to this will return:
  • the number of transmitter messages (.../tx_count),
  • the reconnect count (.../reconnects), and,
  • the power status (.../power).

It's probably worth subscribing to pocsag/status/# if you want these.

Responding to a failure

If there is a failure with this pager node, or it's reported that it is causing interference, it should be powered off immediately. This can be done from jarvis by running

mosquitto_pub -t pocsag/power -m OFF

The default state after plugging in the transmitter is off. If the connection the MQTT server is lost, the ESP8266 will pull the Adafruit Feather's ENable pin low, which turns off the 3.3v regulator, preventing power from reaching the RFM69 module.