The best 13:30 decode was found rank 0: VO1NA ps [ 16 0 0 -30 -30] re-encode 396/1056 ber 3.75e-01 Es/N0=-12.9 Eb/N0=2.6 but when I plot the symbol amplitudes there's obviously a steady drift from a
The 15:00 message found rank 0: VO1NA ps [ 2 30 30 30 30] re-encode 389/1056 ber 3.68e-01 Es/N0=-12.4 Eb/N0=3.1 but I had to use a frequency offset. This time the signal was too weak to see the symbo
VO1NA 2015-12-05 16K21A 5S 5C QRO start Eb/N0 Freq offset 13:30 13.0 -222 uHz 15:00 3.1 -256 uHz 16:30 3.9 -482 uHz Frequency offset is from the peak of the carrier spectrum +/- 1 uHz averaged over t
Maybe the battery here will hold up for another night. This signal could be detectable at long distance except that several dB will be lost unless the rx can correctly guess the frequency offset. Her
Excellent. And a useful link too. I'm sure it can be used for coherent BPSK, although we'll have to work out the best way. You've already done the hard (and expensive) part with the Thunderbolt (good
Ideal if its conversion clock is derived from the XRef board. No good if it has its own xtal though. Digressing a bit... How do you get on with that one, does it work ok? I've been thinking about mak
It was a few hours before I got to the rx to retrieve the battery so it continued on an almost dead battery and recorded two more messages. VO1NA 2015-12-05/06 16K21A 5S 5C QRO start Eb/N0 Freq 13:30
Here I got 'NA' from the 02:00 message at Eb/N0 somewhere below -1.9 dB, BER 47.7%, uniform phase. Very weak because the rx is off while the battery charges and it is receiving only on the feeder or
That looks good, 159uHz is a good choice. Now we hope to see a spike on there from VO1NA. It it reaches 11dB S/N you should be able to do 2 char messages, 16 dB enables 5 or 6 char. With Joe's fairly
Good carrier from you, 14dB in 3600 seconds, that's about -55dB in 2.5kHz, so should be an easy decode of EbNaut. Spectrum peaks at 8269.999979 hz +/- 1 uHz -- Paul Nicholson --
Carrier of DJ8WX measured in about 80uHz bandwidth. S/N is 18.4dB in this bandwidth. http://abelian.org/vlf/tmp/151208a.gif The magnetic flux density of 0.1fT corresponds to around 30nV/m electric fi
Looks like Joe was still sending the 'NA' message, therefore nothing will be visible in the spectrum. Anyway I single stepped through the animated gif but nothing shows up. Hopefully we can try a car
VO1NA spectrum measured over the VK window 09:45 to 11:30 http://abelian.org/vlf/tmp/151209a.gif shows the carrier energy spread evenly across three bins and the S/N here is 14.5 dB. A non-coherent s
18:00 no decode 19:00 Eb/N0 = 4.4 dB BER = 34.1% rank 0 20:00 Eb/N0 = 4.0 dB BER = 34.8% rank 0 Needs about 1.3 Gbyte for this code and message length. Yes, always at least 100% since no I/O to wait
Yes, here I will check vlfrx-tools, I think it's the right polarity but maybe not? I notice when I rx I/Q from an RTL2832 SDR I have to invert Q to get the sidebands the right way round which is susp
Here's my continuation of the carrier plot, http://abelian.org/vlf/tmp/151210a.gif using a frequency of 137776.999810 Hz. I wondered what that glitch was. No obvious peak on Edgar's animated spectrum
