A New Digital Mode For Radio Amateurs

There was a time when amateur radio was a rather static activity. There was a lot of fascination with building radio stations, but what you did with them remained constant throughout the year. The Morse code is sent by hand with a key, the voice was on FM or SSB with a few old-fashioned AM users, and you will hear the flickering tones of RTTY traffic generated by mechanical teletypes.

In contrast, the radio amateur today lives in a fast-paced world of ever-evolving digital modes, in which much of the excitement comes in expanding the boundaries of what is possible when the radio is connected to a computer. A new contender in one part of our hobby came to us [Guillaume, F4HDK], in the form of its NPR or New Packet Radio mode.

NPR aims to provide a high-bandwidth IP network to radio amateurs in the 70 cm range, and does so quite cleverly with a modem that contains a single-chip FSK transceiver designed for use in unlicensed ISM tape applications. The custom board has an Ethernet module and an Mbed microcontroller board, which when assembled produces several hundred milliwatts of RF, which can be fed to a DMR power amplifier.

Each network is configured around a master node designed to use an omnidirectional antenna to which individual nodes are connected. Time division multiplexing is required by the master, so there should be no collisions, and this, combined with the relatively wide bandwidth of the ISM transceiver, gives the system a high usable data bandwidth.

Whether the regime will be used or not and whether it will succeed depends on the will of the individual radio amateurs. But it has the interesting feature of relying on relatively cheap parts, so the barrier to entry is lower than it might otherwise be. If you are wondering where you might see it [F4HDK] before, before we took you his FPGA computer.