In vlfrx-tools I use I = s(t) * cos( 2pi * Fo * t); Q = s(t) * sin( 2pi * Fo * t); where s(t) is the incoming signal and Fo is the local oscillator frequency. Is that right, or should there be a minu
Those Zoom FFT pages show -sin() as the multiplier for Q. But a lot of other sources show +sin(), as I use in vlfrx-tools. Andy's hardware is using +sin and the spectrum is correct in Spectrum Lab bu
https://dl.dropboxusercontent.com/u/101251787/VO1NA/VO1NA%2010-12-2015.gif The 13:45 and 14:00 frames have a peak in the same place as the 10:15 the previous day. http://abelian.org/vlf/tmp/151210b.
Well done Joe, epic 3-day transmission and good data. The full plot http://abelian.org/vlf/tmp/151212a.png The diurnal doesn't repeat very well from day to day but diurnals often don't. But it appear
If the signal is on the high side of the oscillator, Q should lead I after the mixer, s(t) = sin(wc * t); // Signal, wc = 2 * pi * Fc i(t) = sin(wc * t) * cos( wo * t); // LO, wo = 2 * pi * Fo q(t) =
I'm puzzled by the I/Q inconsistency. Is there no convention on the signs in the complex mixer? Perhaps it is vlfrx-tools and ebnaut which needs to change Q sign? I'd like to thank everyone for givin
How about a long carrier, GPS or rubidium? It's a long shot but it's a low loss path and the time of year is good for several hours of coherent integration. I can easily see 10uW from 1000km in one
The radiator, although a horizontal wire, is practically a vertical polarised Hertzian dipole with the ground as one pole and the wire as the other. Horizontal polarisation suffers very high attenuat
SAQ this morning http://abelian.org/vlf/tmp/151224a.gif The full transmission, 13Mbyte mp3 mono 8k samples/sec http://78.46.38.217/saq151224.mp3 And yesterday's 7 minute test that Laurence spotted, 3
DJ8WX active last night with a very good signal here in Todmorden http://abelian.org/vlf/fbins.shtml#p=1450983600&b=070&s=sp I wonder how well this signal would be received in, say Newfoundland? Only
While sitting here slowly consuming my own weight in mince pies, I've been busy with EbNaut and can report some progress. The repeated list decodings during the phase search often produce several dec
Thanks for the patch Jacek. It's a good idea to publish the patch because it'll be a while before I'm ready with the next revision of vlfrx-tools. http://abelian.org/vlfrx-tools I have several of tho
Markus and Domenico on 2015-11-15 8K19A 22 chars 0.3 second symbols. Then some tests with 0.5 seconds 16 chars were successful the next night. Signals were too strong for a good test, too much Eb and
Strong carrier again Uwe, http://abelian.org/vlf/fbins.shtml#p=1451559600&b=080&s=sp I could not decode anything. The following carrier measured 18.4 dB in one hour integration and the signal calcula
I got found rank 4044817 ber 4.0625e-01 Eb/N0 -3.0 M -8.368480206e-02 [DJ8WX] ps [ 4 -30 -30 -30 -30] This counts as a detection, not a decode because it was not the most significant output from the
Nice work! Well done to Riccardo for getting the coherent transmission working. The timing looks good and with the signal available, it'll probably do 0.1 second symbols easily. I don't have anything
That should be 19 chars. I spent 3 days trying to decode, but without success. The following carrier measures 16.4 dB in 1 hour and that should give me Eb/N0 around 0.1 dB which has a good chance of
