Ham Radio Paging: Putting POCSAG On Packet

The KPC-9612 TNC is the centerpiece of Kantronics' packet paging system, with the latest release of the 9612 firmware. supporting the mode. A personal computer may also be used to encode pager messages. TIe weather is bad and you know . your emergency group may be called up at any time, but you can't keep your HT turned on while you're at work. Or you're the repeater trustee "on call" in case anything goes wrong, but your job takes you from place to place. In both of these scenarios, a pager would be just the thing to help you keep in touch. But a paging service is expensive, especially if you want to equip a whole group with them. Unless, ofcourse, you do your own paging...via ham radio. While attending the "Wireless World" conference last December in San Francisco, I managed to take in the sessions on paging. I was curious about twoway paging and the future ofpaging, both of which were advertised session topics. Once the discussions got under way, I couldn't help thinking about the similarities between paging and 9,600-baud packet. Both use frequency shift keying (FSK) modulation and a synchronous data format with check bits for error detection. Once home, I obtained a copy of the International Radio Consultative Committee's (CCIR) Radiopaging Code No. I Recommendation (R-584-1), more commonly known as the Post Office Code Standardization Advisory Group (POCSAG) code. I examined that standard, thought about how to implement it in hardware, and outlined some experiments to try POCSAG paging on the 2 meter band. After checking appropriate sections of Part 97 and running the experiments, Michael Huslig, KB0NYK, Karl Medcalf, WK5M, and I succeeded in porting