Measures 0.12 fT with 15.1 dB S/N in 139 uHz http://abelian.org/vlf/tmp/160419a.gif EbNaut decoder likes it, 6 chars with 8 second symbols of 8K19A at -0.7 dB. -- Paul Nicholson --
Another plot from the same pipeline, all same settings but with the sferic blanker removed http://abelian.org/vlf/tmp/160419b.gif DF6NM is lost in the noise without sferic blanking. Average noise per
I should mention that for sferic blanking to be this effective it is essential to band limit the VLF before the blanker. A broadly optimum bandwidth is 3kHz centered on the signal frequency. Too wide
Great signal here, decoded your message at Eb/N0 = +8.1 dB with constant reference phase. Carrier S/N: 22.64 dB in 65.1 uHz Copied 'GIZMO' with constant reference phase, Eb/N0 = -0.3 dB. Carrier S/N:
In one hour measurements (278uHz), Start Time Flux Phase 2016-04-23_16:30:00 0.10 fT 5.7 deg 2016-04-23_17:00:00 0.07 fT -1.4 deg 2016-04-23_17:30:00 0.07 fT -30.7 deg 2016-04-23_18:00:00 0.10 fT -33
I'm getting a good decode of the message '42', seems like too good a decode to be a false hit: rank = 2, Eb/N0 = +1.6 dB with constant reference phase. -- Paul Nicholson --
Well done Stefan! The first of many successful transmissions I am sure. I also got a nice sharp line at 8270.000 Hz which I hope is Roland. Flux density averages 0.09 fT from 17:00 to 18:00 but the s
Here I am limited to 60m unless I notify the aviation authority (which I don't want to do), so I thought about using 2 or even 3 kites in a row each at 60m, spaced maybe 100m or so. Trying this cheap
Another success. Copied 'DREAMER' at rank 3, Eb/N0 = +0.8, BER 34.5%, constant reference phase. Signal averages 16.04 dB in 54.8 uHz. A good result, considering the overnight noise. -- Paul Nicholson
Thanks for the tip Stefan. The power sled 24 looks pretty good. I just ordered the version with tail, which it claims copes with a stronger wind. I bought line strong enough for the 36 model in case
Sorry Roland, nothing detected here this morning, 07:00 to 10:00 UT on 8270.0000 Hz. The noise floor is 0.01 fT in 93 uHz and the 8270.000 bin is 0.02 fT. Is the transmission going OK? -- Paul Nicho
Copied no problem, with Eb/N0 = +0.9 dB using a constant reference phase. S/N: 19.69 dB in 33.6 uHz 'CQ DK7FC JN49IK' That's three out of three decoded. One day, perhaps I'll be able to reply to you
Yes I remember a time - a few years ago now - that VLF didn't go beyond the back yard, a time when there was talk of dreamers on the LF list and the sound of gauntlets hitting the floor. Did someone
Copied 'SPRING' at Eb/N0 = +1.5, almost constant reference phase: 180 180 150 150 Carrier S/N: 18.63 dB in 29.8 uHz In audio bandwidth: -60.6 dB after sferic blanking, About -80dB before blanking. He
I guess, the most important factor is to avoid the terminators, so set the symbol period so that the message takes all day or all night. The interleaving helps the mode to cope with spells of QRN bu
You can eliminate the transformer by having more turns in the loop. But you'll probably find when you do the arithmetic, that it is cheaper to have fewer turns (or one turn) and a transformer. Also f
The VLF noise last night was spectacularly high, which you can see if you look at the flux density spectrogram, http://abelian.org/vlf/fbins.shtml#p=1461772800&b=100&s=fd You have to scroll back to 1
