Big WOOOwww Stefan !!! :-O
Real fuel for thoughts. My biggest congratulations Stefan :-)
http://www.nasa.gov/mp3/590331main_ringtone_smallStep.mp3
73 de Luis
EA5DOM
-----Mensaje original-----
De: [email protected]
[mailto:[email protected]] En nombre de DK7FC
Enviado el: miércoles, 08 de junio de 2016 11:16
Para: [email protected]
Asunto: ULF: A first step on the 100 km band
Hi all,
I've got a first result with my ULF project: One of the ideas to generate and
radiate a signal on the 100 km band to use a ferrite power transformer with
using two E cores out of N27 material. These are available at
https://www.buerklin.com/de/e-kern/p/83d970
At 2970 Hz i can apply 1 V / turn without saturating the core, maybe even more.
I think i can generate 3 kV (rms) with one transformer without a risk of a
flashover. And i can set an air gap between the two E cores.
For 2970 Hz i need L = 6.1 H! Now without an air gap i need about 800 turns
(hand wound!)to resonate the antenna. So i can apply 800 V now.
On 2970 Hz, my antenna radiation resistance is 70 uOhm. With 800V on the wire
it radiates 6 nW!
The distance to my remote site is 3.5 km or 0.035 lambda.
I'm TXing since last night and got a trace of up to 15 dB SNR in 424 uHz. Quite
weak but it's a first step.
The signal was radiated with an E field antenna and received with a H field
antenna, so there could be a better result in the near field.
I' now planning to wind more turns on the transformer and add an air gap to
keep the inductance and rise the voltage limit.
73, Stefan
|
