Re: ULF: Key down signal on the 101 km band, still on the air

[DK7FC <selberdenken@posteo.de>]

Hi Uwe,

What a surprise :-) 6.6 uHz... But that will not be enough i fear. Anyway, its interesting and you know the stories about the neighbours garden fence :-)
Don't worry, the carrier will stay on the air. Renatos 1.26 uHz spectrogram will show a first pixel this weekend i think :-)

SpecLab is coming to its limits (again)! The highest decimation factor is now choosen and still not large enough :-)
On Renatos grabber i had to use a very large FFT input size to come down to 1.26 uHz. Who has ever expected that we deal with bandwidths in the sub-microhertz and scroll rates of 2 days per pixel/spectrum :-)

BTW now i have successfully optimised my portable loop for 2970 Hz. It is a 40m long wire with 4 strands switched in series, about 600 uH inductance. Then a 10:200 (turns) transformer follows and a simple NPN preamp powered by the soundcard. The loop is resonated to 3 kHz with a flat peak, low Q.

In the coming days there will be thunderstorms again but next week i'm planning to do the next receive experiment, the first time into the far field, > 16 km. With some luck there will be faint traces in 424 uHz in thge morning hours. It should be clearly visible in 47 uHz. I'm going to search for a quiet location now :-) In this test, the plan is to record 2 days and post-process the data then.

73, Stefan

PS: It looks like the dryer the soil, the higher the antenna current. At least i'm now seeing almost 31 mA whereas it is just 29 mA after a rain.

Am 19.07.2016 14:52, schrieb uwe-jannsen@kabelmail.de:

Stefan, Paul;

<if you want to switch off?>

pse do not so. Im trying too.
yesterday I reduced the FFT-bin in SL to 6,6uHz. it will last some days until SL works agn (30% acquisition now).
next days Ill reduce the bandwidth agn.

Uwe/dj8wx


 

Von: Paul Nicholson <vlf0403@abelian.org>
Gesendet: 19.07.2016 07:03
An: <rsgb_lf_group@blacksheep.org>
Betreff: Re: ULF: Key down signal on the 101 km band, still on the air

 

Stefan wrote:

> any results in a bandwidth < 1 uhz ?

so far nothing, not even in 0.6 uhz.

but the noise level is much higher than it could be. have to
work on the filter and blanker settings. will take some
time but i suspect a detection is possible.

i probably have enough signal recorded by now (!), if you
want to switch off?

--
paul nicholson
--

1="" uhz="" so="" far="" nothing,="" not="" even="" in="" 0.6="" uhz.="" but="" the="" noise="" level="" is="" much="" higher="" than="" it="" could="" be.="" have="" to="" work="" on="" the="" filter="" and="" blanker="" settings.="" will="" take="" some="" time="" but="" i="" suspect="" a="" detection="" is="" possible.="" i="" probably="" have="" enough="" signal="" recorded="" by="" now="" (!),="" if="" you="" want="" to="" switch="" off?="" --="" paul="" nicholson="" --=""></ 1 uhz ?

so far nothing, not even in 0.6 uhz.

but the noise level is much higher than it could be. have to
work on the filter and blanker settings. will take some
time but i suspect a detection is possible.

i probably have enough signal recorded by now (!), if you
want to switch off?

--
paul nicholson
--

>