PI TNC - progress report.

John G8BPQ

For those new to the group, I have been working on a TNC for use with the pI that is the same size as the pi and plugs into the expansion header. The prototype was a TNC-X, with a 26 way header superglued to board. There is a photo of it on the home page of this group.
I now have two TNC's running, and can connect between them. See photo at https://dl.dropbox.com/u/31910649/IMGP0573.png. This show the prototype - the production boards will have a DB9 instead of the Mini-DIN radio connector. A batch of production boards has been ordered, and should be here in 2-3 weeks.
I've also built a couple of units using the RMF22B 100 mW 434 Mhz tranceiver model. They both transmit - I now need to get the receive side working. There is a photo at
I looked at the higher powered (500 mw) RMF12BP, and ordered a couple for experiments. But when I looked into the module in more detail I found it was not compatible with the RFM22B, and is less flexible and more difficult to program. I've since found the RFM23BP, which is a 1 watt unit that is compatible with the RFM22B, so I've ordered a couple of them for testing, and designed a board that will take either the 22B or the 23BP. Although it is primarily indended for use with the PI, it will also have an async port, so it can be used as a standalone KISS TNC/Radio.
73, John G8BPQ

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