---- Nate Duehr <[EMAIL PROTECTED]> wrote: > Scott, > > Here's a highly filtered version that MAYBE a TNC or a sound-card packet > program could be fed with the copy the packet.
Verrry interesting! If I get a chace tonight I'll try to decode the packet. My guess now is that it is a mix of two signals, one being a packet signal and the other using the Kenwood DTMF signalling format. I used the Kenwood DTMF signalling on my repeater for years. When someone used the phone patch the repeater sends 000 before dialing the number. I used this to open the squelch on my TM-741A here at the house so that I can listen for abuse of the phone patch. It worked quite well in the past, but use of the phone patch has fallen off over the years. I don't remember the last time it was used. Why someone would be using the Kenwood signalling is the big question. 73, Joe, K1ike > > It's very obviously standard Bell 202 packet tones once you high and low > pass filter the crud out of it, and take out the offending DTMF as much > as possible. > > http://www.natetech.com/files/Signal_3-filtered.wav > > I left the clicks in (zero-crossings from the DTMF generator sending the > zeros) as I'm not a packet expert and couldn't tell you if chopping > those out in the middle of the packet waveform would screw up the timing > or blow away the CRC of the packet. > > In fact, it sounds like the end of the packet might be chopped off, so > you might need to put whatever's copying it into a "ignore CRC error > correction" mode and just go for the raw stuff and see if you can make > anything out of it. > > Nate WY0X > > p.s. I used a free program called Audacity and some free filters found > on the Net to hack on the original WAV file you sent. I may have > over-done it a bit here, but man is that packet audio weak in that > original file! I amplified this quite a bit, which added noise, and > then low-pass filtered off the high end to get rid of the hiss. I also > chopped the white noise off the front and back. > > > > > > Yahoo! Groups Links > > >
