I wondered what that was. In a narrow bandwidth it's a big ugly blob of an un-disciplined oscillator and very strong. LF is a busy band! Looks like the signal from VO1NA has gone now anyway. Timing s
I think so, the rx itself hasn't had any problems. The timing system has got better too with the incentive to reduce the jitter without sacrificing speed of response to clock drift. It seems that whe
Could not decode the 23:00 message, either at 137.777 or 136.5. Going by the carrier measurements the other night it should be strong enough to get a reference phase, therefore a quick decode. Lookin
Great. My rx is recording again with a fresh charge in the battery. Should I be looking for your carrier? Can you reach 20uW ERP, GPS locked? If so, try sending 2 hours of unmodulated carrier between
You're right. It's impractical to search for. The only way is to prefix the message with a spell of carrier long enough to measure F. But strictly speaking that carrier should be included in the over
Success! 21:00 message decoded re-encode 130/608 ber 2.14e-01 Es/N0=-5.0 Eb/N0=6.6 Now I am privileged to know the secret of the cat's name. -- Paul Nicholson --
Your reported carrier Eb/N0 = 0.93 dB but the symbol errors give Eb/N0 = 9.5 dB Have you got some other signal in the passband of the I/Q signal? -- Paul Nicholson --
I just realised from your log Markus, you ran the decoder on half a message. I guess the interleaving is doing its job then. I'm not sure the symbol error counter is reporting correctly when half the
Excellent result. That's the sort of test I like to see, where Eb/N0 = 0.7 dB and the program will have had to search for the phase and it had to use some list decoding. That's a proper weak signal t
Thanks to all for the interesting tests. But we are battling with clocks and oscillators rather than propagation and noise. At least with EbNaut nobody can complain that the operator is just installi
Good idea, I'll try it. I wouldn't like to stand up and justify that to a professor but it could do better than the alternatives - at least BER will always be below 50%. There will still be problems
My earlier decodes of VO1NA, time Eb/N0 Phase 21:00 9.6 30 30 30 30 21:30 13.3 0 0 0 0 (offset 1.8 seconds) 22:00 12.0 0 0 30 30 22:30 10.8 150 150 180 180 And taking further advantage of the time of
Signals from VO1NA, 2015-11-25/26 So far decoded: time Eb/N0 T-Offset Phase 00:00 no decode 00:30 no decode 01:00 10.8 dB +2.9 0 0 30 30 01:30 8.4 dB +4.2 -90 -90 -60 -60 02:00 9.7 dB +5.7 -30 -30 0
Final result time Eb/N0 T-Offset Phase 00:00 no decode, tried very hard 00:30 -0.8 dB +1.8 -30 -60 -60 -90 (rank 35975 BER 36.8%) 01:00 10.8 dB +2.9 0 0 30 30 01:30 8.4 dB +4.2 -90 -90 -60 -60 02:00
Decoded straight away with zero T offset: found rank 29: VO1NA ps [ 1 180 180 180 180] re-encode 184/512 ber 3.59e-01 Es/N0=-11.8 Eb/N0=0.5 effrate=1/17.07 I'll try sweeping in the T dimension to see
Message: 5 chars Coding: 8K19A Symbols: 512 at 2 seconds each Duration: 1024 seconds, 00:17:04.00 Best decode here is at T offset +0.8 Eb/N0=5.4 phase 150 150 180 180 I run 10 copies of the decoder i
