This month, we’ll have a close look at the final assembly of a TARPN node (Photo A). It’s been in progress for some months now, and I think I’m finally ready to explain how. If you are interested in further details, be sure to visit the ‘builders’ page on the TARPN website <tarpn.net>, where very detailed and useful instructions and commentary can be found.
If you remember, we started with a bunch of NinoTNCs, ordering the bare boards and programmed processor, along with the myriad other parts, from DigiKey or Mouser. At only around $40 each, NinoTNCs are the ultimate bargain. Assembly took some time but was not particularly challenging. In fact, the only error I made was installing one of the switches upside-down. I suppose I could unsolder and rotate it, but getting out and setting up my homemade desoldering iron is an unpleasant task. What I really need is another workbench. Perhaps I’ll write about that sometime.
Then came the radios, of various vintages, manufacturers and modification status. At the moment, the Tait 8105s and Yaesu FTM-3100s are the 9k6 candidates, while the $5 Kenwood TK762Gs are probably going into 2400-baud service. Each radio needs a cable for the four TNC signals (PTT, RX audio, TX audio and ground) with a DE-9M connector on one end (for the TNC) and whatever the radio needs on the other
