I think about 830km to Frankfurt. Perhaps Stefan can give the lat/long of the tx site? The rx here is at 53.703N 2.072W. Looks like Stefan has finished sending now. The noise level here is coming up
Thanks for the test - loads of data to analyse here. Lots of whistler activity right now, UK, Germany, Italy http://abelian.org/vlf/test.html -- Paul Nicholson --
Can a thin wire be suspended between two kites, 100m or more apart? The resulting catenary (Oberleitung?) should add considerably to the capacitance (extra ~480pF?) and raise the overall effective he
Yes, Alpha amplitude was logged at the same bandwidth during the test. The average amplitude of the central 11904.761Hz component during the 90 minutes analysed was 11.6fT, but there is probably 50%
2 metre whip or wire, short wire connection to low noise JFET pre-amp, 10MOhm bias resistor, battery powered, ground resistance < 500 ohms, coax to house, transformer to break the ground loop. If pos
Stefan schrieb: 1/sqrt(d) is doing better than 1/d, so far with just one data point to go by. There is also an attenuation factor. Approx 3dB per 1000km in daylight, and 2dB/1000km at night, at 10kHz
Conditions right now are perfect, http://abelian.org/vlf/nb.shtml Very low background noise, oriented mainly North/South, no lightning storms in Europe. Hope it's like this tomorrow! Stefan schrieb:
Here's a live spectrum for 8970 +/- 1Hz - resolution is 5mH. Amplitude calibration is only within a factor of two or so. http://abelian.org/vlf/nb.shtml Ich habe die Frage gestellt. -- Paul Nicholson
After my post yesterday I realised there is one more thing I can do here to the rx. I have an E-field rx running too, if this was combined coherently with the loop antenna, some further directivity m
Here is an interesting peak on the spectrum, http://abelian.org/vlf/tmp/ss100315a.png Frequency is 8970.0098 Hz +/- 2.5mHz. Bearing of this signal was 117/297 deg. Frankfurt is on 114. I've added a s
Stefan schrieb: Pure carrier doesn't have to be continuous, eg separate 10min transmissions. Non-coherent averaging can use disjoint periods so long as you note the UT start/finish of each. Yes, no n
Sorry I left a couple out, try again: Michael Oexner: 72km Wolf DL4YHF: 264km Renato IK1QFK: 544km Markus DF6NM: 179km Uwe DJ8WX: 461km Henny PA3CPM: 367km Jim M0BMU: 665km Victor PA3FNY: 360km Paul
My best effort at a spectrogram, added to end of http://abelian.org/vlf/ss100321/ Produced after re-running the signal processing without clock correction. The spectrogram is normalised for uniform b
I'm inclined to agree. The ERP is low and should only be a problem to a research station near to a tx, which could be dealt with on individual cases. I should think the lightning locator networks wou
Sorry, that should have been Pure and applied geophysics, (volume price $110, single articles a mere $34! I can get copies through the British Library but it takes weeks). It's a challenge - those Le
Wolf schrieb: Or, mix of ground and sky wave, very slight Doppler separating the two paths as the D-layer starts its evening performance? -- Paul Nicholson --
In order to squeeze out the maximum S/N, it looks like a loop antenna is desirable in order to null as much background noise as possible. It must 'see' down to the natural VLF background, so a basic
No, there is a pre-amplifier using LT1028 op-amps. Input transformers match the 20 square metre loops to the op-amps for optimum noise performance. The 'receiver' is calibrated using the thermal nois
This would be the most straightforward explanation for the high signal strength. The signal expands with 1/r^2 power density and 1/r field strength until it is constrained by the Earth-ionosphere cav
Some daily plots of the background noise amplitude at 8.97kHz, each point averaged across 12Hz for 120 seconds, and rescaled to 1Hz bandwidth: http://abelian.org/vlf/live/100305.9kHz.png http://abeli
