Re: VLF: Now on 5170.0025 Hz

[Markus Vester <markusvester@aol.com>]

Danke Tom! That's a nice report. Distance between us would now be a bit under a wavelength ;-)

As the antenna current dropped further to 0.13 A, I decided to interrupt the transmission and take a look. The coil was actually cold to the touch so the reduction was not due to temperature-dependent copper resistance.  However that tuning had gone down by more than 100 Hz, probably due to the yoghurt cups sinking slightly into one another, an effect which Stefan had also observed earlier. Being eager to get on air, I hadn't used Lego spacers between all of the cups. Inserting some more shims has now restored the resonance and original current. I will try to keep the carrier on air till the evening.

Best 73,
Markus (DF6NM)



-----Ursprüngliche Mitteilung-----
Von: DK1IS <DK1IS@kabelmail.de>
An: rsgb_lf_group <rsgb_lf_group@blacksheep.org>
Verschickt: So, 12. Mrz 2017 14:52
Betreff: Re: VLF: Now on 5170.0025 Hz

Hello Markus,

also a clear trace with 30 mHz in the Oberpfalz:  S/(S+N) = 5 dB at a signal level of -148,6 dBm. RX Perseus at DL0AO (JN59VK53NK), ANT Beverage 200 m to South America - on VLF certainly a large lossy earthloop. The enclosed waterfall is evidentiary but rather short - I didn´t want to block our RX stn longer.

73 and good dreams,

Tom, DK1IS
www.qrz.com/db/dk1is

Am 12.03.2017 um 14:01 schrieb Markus Vester:

Thank you Stefan! Yes indeed, I'm glad to see a solid trace on your EW tree-antenna. Having a sensitive grabber within reach is rather motivating.

Attached is a pic of the coil preparation, a temporary "ugly construction" with some chunks of ferrite inside. In the meantime the current has dropped to ~ 0.15 A due to self-heating of the thin wire but it seems to be stable now.

Best 73,
Markus (DF6NM)


-----Ursprüngliche Mitteilung-----
Von: DK7FC <selberdenken@posteo.de>
An: rsgb_lf_group <rsgb_lf_group@blacksheep.org>
Verschickt: So, 12. Mrz 2017 12:57
Betreff: Re: VLF: Now on 5170.0025 Hz

Hello Markus,

It looks like you are there!! Even in 424 uHz. Very good, my congrats! You are the second station transmitting on 58 km at all!
EbNaut should be no problem there, good luck.

73, Stefan

Am 12.03.2017 12:26, schrieb Markus Vester:

I've managed to tune to 5.17 kHz and am sending a straight carrier since 11:18 UT. Due to the high coil resistance the antenna current is only 0.18 A (as opposed to 0.4 A on 8.27 kHz, thus 11 dB less ERP). I wonder if the signal may show up in Heidelberg...

Best 73,
Markus