It is simple:-) Trees effect to a loop is much lower then such an effect to an E-antenna. This is why loop is better then E-antenna in bad enviroment (trees). While E-antenna is better then loop of t
Seems noise level depend strong on the location. Anyway it is obvious for industrial noise. Theory confirm this empirical rule. Few years ago i do some a theoretical study of optimal signal reciepti
Dear Jim, with such a noise Stefan's signal should be detectable in QRSS100 at 100 km. Seems to be worth if such noise level takes place every day and every night. It is naturally to assume noise le
It does not matter where capacity conected: at the end of inv-L or at the feeding point. Add condenser Cp between ground stake and antenna! Then a foil is needless. Regards, Alexander
Rik, after some theoretical estimations done i am absolutely shure QRSS communications at few 100s km (may be more) is posible on 9 kHz. There is lot of problems on TX side but them to be solvable.
Andy, certanly AFTER filtering noise became gaussian. But matter of fact is that if noise is nongaussian then to get optimal reception one should make some nonlinear processing (limiting in simplest
Ground resistance is not worth in such a conditions. Coil (or high voltage transformer) resistance is much grater anyway. Thus use the single short ground stake and don't worry about it. It is much
Hellow, Stefan. With such a condition you'll get about 2.5 uV/m at 100 km. Seems it can be recievid. If there is no atmospheric and industrial noise it should be very strong signal. But all depends o
Yet another 5 dB! Then we have 5 dB over noise at 1000 km (!!!) in QRSS100. In HAM practics we don't need regulary contact. Thus let's take lowest noise level. Certanly this is very rough estimations
Dear Markus, In what qrss mode (FFT-bandwith) you resived such a signal? P=1uW D=6km yelds E=1.3uV/m It seems to be usefull to estimate noise level. But we should normalyze this to bandwith. Regards,
You can decrease L only by condenser in parallel with a antenna. But then only part of coil current will flow thrue the ant (and ground stake also). Let's describe some numerical example. Let antenn
Unfortunely i have very few time for ham radio. But i read this group regulary. Usualy i don't write here now. But about VLF i wonder to point out that for near field antenna voltage is more worth t
This calculations is for far field. But in this case near field is more significal if distance << lambda. For near field one can derive simple formula (extremally approximative!) U_{RX}=U_{TX}(h/D)^
MNI TNX Markus. Thus noise level on 9 kHz can be expected abt 1.3*SQRT(1/0.063) = 5.2 uV/m in 1 Hz by this data. Essentually less then Jim mesured. Thus Stefans sigs with 20 kV on kite ANT should be
Why? It is for 175 dB noise level, not for lowest 155 dB level. For 155 dB it changes to 6.5 uV/m in 1 Hz. In 0.01 Hz (QRSS100) it yelds 0.65 uV/m. 2.5 uV/m is ~10 dB over noise. Right? Regards, Ale
Yet another comment. Today a have find some web page (www-star.stanford.edu/~vlf/south_pole/south%20pole.htm) where presented waterpole picture with some signal E ~ 4uV/m near 10kHz. It is dificult t
I don't think it is real ground stake loss. Mainly it is 'enviroment' loss (due to trees, house e.t.c.). I don't think so. This behaviour should change. Good insulator (HF frequency) or good conduct
I was wonder if it is posible to use a loop on 9 kHz. Serious problem to radiate 9 kHz is high voltage we saw. Loop has that advantage that voltage is not too high. Then i do some estimations. Let's
