New Packet Radio

A "new" New Packet Radio (NPR-H) that is compatible with the one you may know!

I was amazed by the work of F4HDK. And as a ham radio guy who was active in packet radio in 1999 and the years beginning of 2000s I wanted to have something faster. Hamnet is nice, but you cannot have that long range transmissions as on 2m or 70cm bands.

The modem I build is compatible with F4HDK's hardware and firmware and can be used for ham radio guys as a standalone long range communication bridge, entrance to Ham radio, bridge between networks etc. It can handle up to 1 MBit/s data transfer between up to 8 NPR-H modems that communicate in 433 MHz band (70cm ham radio band). Connect a PC device to the network port of NRP-H and the modems will handle the rest.

Additional Features

• Ethernet + PoE capabilities, a single cable for power and data! The modem has a build in PoE power supply, so you can use it directly from an Ethernet PoE source.
• LNA build in, 13dB gain.
• PA build in, output power up to 25 dBm. Additional "OMPH!" increase the range in 70cm band. (additional GPIO Pin to drive additional power amplifiers).
• SRAM 1024K to speedup things.

Price

Unfortunately, the PoE part, SRAM, LNA and power amplifier increased the BOM. But therefore you get performance. From the sales price, some USD per piece is donated to my ham radio club O28, depending on whats left after USD-EUR conversion, bank fees etc. Thanks for your support!

What do I get?

The PCB hardware comes flashed and tested, shipped from Germany. You can for sure reflash it using an ST-Link. GPIO Ports are accessible on the PCB.

Enclosure

The PCB fits into standard HENSEL IP67K enclosures. I used these as I planned to mount the modem closer to the antenna and connect it with a standard network cable. You will need to drill holes yourself. If you want an enclosure, please let me know via message. Alternatively, I do have other enclosures which fit as well but need some mounting work to hold the PCB (e.g. 3 bolts + 3 nuts + glue).

Where is the firmware? I want to program myself!

If you want to programme in F4HDK's firmware, which is available and open source on hackaday please have a look on the links below.

The firmware from F4HDK does sometimes not recognize the RF chip. This behaviour is also mentioned in his documentation. This can be realized once the TX LED is permanently on after boot. A workaround is to let the hardware warm up for 2 minutes then reboot.

Links to hackaday:

• https://hackaday.io/project/175907-npr-h-new-packet-radio-modem
• https://hackaday.io/project/164092-npr-new-packet-radio