[aprssig] RFM22B UHF Transceiver Module

Thomas Krahn thomas at tkrahn.com
Wed Dec 12 12:00:01 EST 2012

On 12/12/2012 08:27 AM, Jason KG4WSV wrote:
> Our cubesat students are working with some modules that I think are 
> based on the same chipset (TI CC1100 ?) and are having some challenges 
> getting 9600 baud AX.25 working. I think the ham equipment receives 
> their data fine, 
I'd be interested in doing exactly this. Do you have any pointers how 
this could be done? How do the modules do the scrambling? Or do I need 
to do this by myself in software?
Also my understanding is that the RF modules only accept input data in 
byte format, not bitwise. Therefore in my understanding we'd need some 
non trivial conversion with overflow bits to implement AX25.

> but the module doesn't receive the AX.25 data. 

Not so much a problem for trackers. I'd be happy to get transmit 
working. There are plenty Hams out there with Kenwood radios or similar 
that could receive 9k6 GFSK.


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