R: Re: R: SLF: Carrier transmission at 80 Hz

["marcocadeddu@tin.it" <marcocadeddu@tin.it>]

Hi Markus,

are you meaning DC as direct current or District of Columbia? :-))

have a nice weekend MF / LF fellows!

Marco, IK1HSS

----Messaggio originale----
Da: markusvester@aol.com
Data: 23-nov-2018 22.33
A: <rsgb_lf_group@blacksheep.org>
Ogg: Re: R: SLF: Carrier transmission at 80 Hz

Wait until Stefan reaches DC! Then when the sun doesn't shine, he can connect the receive antenna on the tree to the battery ;-)

73, Markus



-----Ursprüngliche Mitteilung-----
Von: marcocadeddu@tin.it <marcocadeddu@tin.it>
An: rsgb_lf_group <rsgb_lf_group@blacksheep.org>
Verschickt: Fr, 23. Nov. 2018 16:36
Betreff: R: SLF: Carrier transmission at 80 Hz

ehm... some time ago I wrote here that there were worries at the Pentagon :-))))
 
simply incredible!

If next weekend I ear some hum coming from my devices now I know who is guilty! ;-)))

FB

Marco, Ik1HSS

----Messaggio originale----
Da: selberdenken@posteo.de
Data: 23-nov-2018 10.21
A: <rsgb_lf_group@blacksheep.org>
Ogg: SLF: Carrier transmission at 80 Hz

Dear SLF friends,

A new step forward towards DC: Since yesterday 22:30 UTC i'm TXing a carrier at 80.005 Hz. That's the 3750 km band, where the far field begins at a distance of 598 km.

The antenna voltage is just 5 kV and i'm getting 1.2 mA antenna current, giving an ERP of  20 fW (2E-14 W).

The voltage is even higher than in my recent experiment on 270 Hz, anyway the S/N is lower, indicating that my RX lacks of sensitivity. Indeed this experiment helps to estimate the lack of sensitivity. Looks like i'm missing about 10 dB on that frequency. Anyway the signal is making the path of 3.5 km to my tree grabber, as usual shown at http://www.iup.uni-heidelberg.de/schaefer_vlf/DK7FC_VLF_Grabber2.html. Not a big distance but still well beyond most garden fences!
The signal leaves a barely visible trace in the ZEVS window which is running at 3.8 mHz FFT bin witdh. Unfortunately ZEVS is off the air since a week or so. actually i wanted to transmit side by side with ZEVS, of course a bit deeper even.

>From a quiet period at night, i calculated the SNR of a 1 hour carrier period using vlfrx-tools: carrier S/N: 16.83 dB in 277.8 uHz, -18.73 dB in 1Hz

For the crazy homebrewers i'd like to share that website where i ordered the HV-transformer, http://www.hosin.de/Specials/HV-Trafo/hv-trafo.html A nightmare for all safety-fetishists! For the completeness it must be mentioned together with that page: http://kurts-werkstatt.de/hv-trafo.htm

73, Stefan