Adam, I apologize if I'm misunderstanding your question. But the packet decoder in GNU Radio is not an AX.25, just a general purpose decode. I've hacked together an AX.25 receiver with the N200. I can send the files to you tomorrow.
-John On Wed, Jun 6, 2012 at 3:52 PM, Adam Gunderson <agunder...@ssel.montana.edu>wrote: > Hello, > > We are currently trying to setup a ground station for GMSK modulated AX25 > packets at 9600 and 19200. > > Our current setup that works is the USRP N200 through GNU radio audio sink > and to a Kantronics 9612+ TNC (gmsk_demod.png, quadrature demod -> audio > sink). What we want to do is replace the hardware TNC with GNU radio packet > decoding blocks and send the packets over TCP. > > We first tested the loopback through all the gmsk mod/demod and packet > encoder/decoder blocks, (gmsk_loopback.png) and this works fine. > > However, when we send our received AX.25 packets through GMSK demod -> > packet decoder -> TCP sink (gmsk_demod.png) we do not see anything on the > TCP server side, which tested fine in loopback. > > We are assuming the hangup is in the packet decoder block as it is not > recognizing AX.25 packets or possibly at the end of the GMSK demod block. > > Do we need to look into writing our own packet decoder block? If we need > to do this, is there a good guide on how to edit existing blocks, or look > at their work() functions? > > Do we need to also implement a derandomizer block before we even can start > making sense of the bit stream? > > If we were able to get a byte stream with the framed AX.25 packets as an > output from GNU radio to our TCP server we can deframe them there instead > of in GNU radio, but we cannot get any output with this current setup. > > We have also looked at trying to get the GMSK Spacecraft Groundstation > project to work but the versions must be out to date because the files > located on https://www.cgran.org/wiki/GMSKSpacecraftGroundstation won't > make. > > Thanks > > -Adam > > -- > Adam K. Gunderson > Space Science and Engineering Lab > Montana State University > agunder...@ssel.montana.edu > > <agunder...@ssel.montana.edu> > > _______________________________________________ > Discuss-gnuradio mailing list > Discuss-gnuradio@gnu.org > https://lists.gnu.org/mailman/listinfo/discuss-gnuradio > >
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