I've been talking to a few of you about a project to finally make it easy to do great digital on 2 meter or 70 cm. The use case is both emergency communications, based on our frustrations with FM voice and our needs in the Rockaways during Sandy, and APRS and similar modes, based on our frustration with AFSK over FM in Manhattan.
Right now I've ordered some RFM23BP transceiver modules, which can operate on the entire 70cm amateur band and also 433 MHz ISM. The plan is to do 9600 bps GFSK, and to test for compatibility with other chips, for example ADF7023 from Analog. There's also a similar part from Silicon Labs. RFM23BP is easier to get started with since it has a single ended 50 ohm RF output. It can't quite do GMSK with typical bit rates because deviation has to be a multiple of 625 Hz. I'm thinking we might try 9600 bps with 2500 Hz deviation. (That's carrier to peak, not peak to peak. I think.) The final product might be a circuit board with USB serial, possibly Bluetooth LE for communication with phones, a battery charging IC, and a lithium ion battery. _______________________________________________ Radio mailing list [email protected] https://list.hackmanhattan.com/listinfo/radio
