Re: LF: ELF communications ?

[DK7FC <73dk7fc@googlemail.com>]

Hi Markus,

Thanks for the calculations. We will see the results.
I do take care. In my promotion project at TU Darmstadt i daily worked with a capacitor battery having 15 kV / 12000 uF, see an image showing 1/3 of the battery at https://dl.dropboxusercontent.com/u/19882028/IMG_8073.JPG Would be fine for a tube PA ! :-)

Once again the PA has some EMC problems and i cannot run the full power. Hope to fix that tonite...

73, Stefan


Am 09.10.2014 18:35, schrieb Markus Vester:

Stefan,

 

this could work. In the capacitive near-field range, the electrical field would be

 

 E = voltage * capacitance * effective height / (2 pi epsilon0) / distance ^3

 

With 10 kV on your antenna capacitance and height, you'd get about 0.15 mV/m at 2.4 km, maybe 14 dB stronger than ZEVS.

 

Take care! Touching 10 kV on 136 kHz will severly burn you. But on 136 Hz it would kill you, unless the current is safely limited to a few mA. 

 

73, Markus

-----Ursprüngliche Mitteilung-----
Von: DK7FC <73dk7fc@googlemail.com>
An: rsgb_lf_group <rsgb_lf_group@blacksheep.org>
Verschickt: Do, 9 Okt 2014 2:51 pm
Betreff: LF: ELF communications ?

Hi ELF, 

  

 This afternoon i'm attempting to transmit on my INV-L on 136.172 Hz (not  

 kHz!). Just preparing my H bridge VLF PA and i intend to use an old 10  

 kV transformer which i got from an old furnance (to inflame the oil  

 stream), see  

 https://dl.dropboxusercontent.com/u/19882028/VLF/10kV%20Trafo.jpg 

  

 Will that work on 2.4 km distance? It's well inside the near field.  

 Which mode could be possible? QRSS-3? CW? 

 The 2200000 m band, or 2.2 Mm band :-) A near field of 350 km !! 

 I hope i can apply 10 kV to the antenna. It will not be resonated. And  

 maybe i will see harmonics as well, because the input is rectangular... 

  

 73, Stefan/DK7FC