Here is my reception report... Transmitter: Amateur radio station DK7FC transmitting from 49.77647N 8.699525E, (near Frankfurt) on 8970 Hz, ERP estimated at up to 1.7mW, vertically polarised CW. Rece
It looks like Horst Stöcker is using 8.79kHz and Stefan Schäfer is on 8.97kHz. Anyone else? The crucial factor is the level of natural VLF background noise after sferics have been removed. A couple o
The signal was strongest up to 15:00, very narrow bandwidth too. Then there was a gap until about 15:20 or so, when the signal came back weaker and with some spread until just after 16:00. It is impo
Stefan schrieb: The rx is not calibrated, nor have I looked at background variation. I will set up something to record relative average background, we can see what the diurnal looks like and pick a g
Absolutely agree with Jim, those bias resisters are the worst possible value - maximum noise match! Must be at least 10 times that for the small antenna. Intermod can be a problem here too - very har
Yes it's coming through Wolf. 11904 checks out ok. Signal is clipping rather a lot, hope that doesn't mess up the noise floor. Background still low today, hope the bearing shifts further North/South
Nice reception. Here are some spectrograms made from the on-line receivers, Bielefeld - Wolfgang Büscher, DL4YHF, http://abelian.org/vlf/live/vlf6.sg.png Cumiana - Renato Romero, IK1QFK, http://abeli
The usual practice would be to have the preamp right next to the loop and the coax between preamp and soundcard, with an isolating transformer to help keep interference at bay. With an unbalanced uns
Stefan Schäfer schrieb: The charge distributes itself for minimum potential energy, so it concentrates somewhat towards the ends. Actually the concentration isn't all that much, only about 10% greate
True enough, the impedance into the coil would typically be much higher than 50 ohms. Tapping into the coil in the manner described, or more likely, using a tapped cored transformer, would bring the
Stefan wrote (another thread): Yes, I think so. Always seems to be there. I am using F1 at 11904.761 for frequency lock. I would need to know details to help. As you say, it is not too difficult to r
Yes, they're from the RSDN-20 'Alpha' system. 11.904761 kHz, 12.648809 kHz, and 14.880952 kHz. These signals are quite strong and the first two are useful for frequency calibration. More info availab
That is very nice. Herzlichen Glückwunsch an Stefan! This evening I will analyse the signal further - it is very faint and may not have much significance (statistically) but is nice to see and most
Good luck with the test Stefan. Today looks like a good day - no thunderstorms in Europe, low background noise, less than 0.7fT in 5mHz this morning and it is still falling. Rx here has been recalibr
Stefan schrieb: I was thinking in terms of, say 100W from a 12V supply, so you'd want to offer a load of less than 1 ohm to the PA. I'm not sure what use an SWR meter would be. I think the only measu
Spectrum displays from receivers in Florida and Italy for today's test: http://abelian.org/vlf/nc.html Frequency calibration is only approximate, so 4Hz wide. No amplitude calibration available. Will
I have taken the liberty of gathering everyone's spectrograms into a table, http://abelian.org/vlf/ss100321/ I'll leave mine out until I have time to reprocess it, but first I have 1600 whistlers to
I think the signal was a little stronger this time. But I'm afraid, not clear enough to decode. Yes I can see the two K, but only when I know they are there. If I didn't know what the message was, it
