Message-ID: <59D2BD65.4080909@posteo.de>
Date: Tue, 03 Oct 2017 00:27:49 +0200
From: DK7FC <selberdenken@posteo.de>
User-Agent: Mozilla/5.0 (Windows; U; Windows NT 6.1; de; rv:1.9.1.8) Gecko/20100227 Thunderbird/3.0.3
MIME-Version: 1.0
To: rsgb_lf_group@blacksheep.org
References: <15ec7c794b3-bff-66@webjas-vac136.srv.aolmail.net> <alpine.DEB.2.11.1709281937520.734@mailn.lipkowski.org> <59CD5C56.7000103@posteo.de> <alpine.DEB.2.11.1710022138560.734@mailn.lipkowski.org>
In-Reply-To: <alpine.DEB.2.11.1710022138560.734@mailn.lipkowski.org>
Subject: VLF: 300 mA on 6470 Hz
Content-Type: text/plain; charset=ISO-8859-1; format=flowed
Content-Transfer-Encoding: 7bit
Sender: owner-rsgb_lf_group@blacksheep.org
Precedence: bulk
Reply-To: rsgb_lf_group@blacksheep.org

Hi VLF,

Since 22 UTC, a carrier with 300 mA antenna current is running at 
6470.005 Hz. The ERP is about 50 uW.
That's the next step in the series of experiments transmitting on 
frequencies down to DC :-)

The coil has 3 and 1/2 stacked buckets now. That gives about 1.3 H. It 
was necessary to separate the upper and lower two buckets a bit more 
than usually, otherwise the frequency was at 6223 Hz. I expect i will 
reach 5170 Hz when the spacing is reduced to the normal value (70 mm) 
and when i fully wind the upper bucket.

Here's an image of the construction as it was used on 8270 Hz: 
http://www.iup.uni-heidelberg.de/schaefer_vlf/VLF/8270_new_coil.jpg The 
new construction uses one more of these buckets.
They say there will be strong rain during the whole night. I don't yet 
know how this will detune the antenna. Maybe the safety circuit tripps. 
But if not, i intend to run the carrier for 24+ hours, so people can 
check their grabbers and phase and so on :-)
A first EbNaut message will follow during the week...

73, Stefan


Am 02.10.2017 22:02, schrieb Jacek Lipkowski:
> Stefan, thanks for the carrier, this helped me improve my grabber a bit.
>
> i've changed the time range in my grabber to 7 days, so that you can 
> compare with your previous carrier, and also added a "normalised" 
> spectrogram:
>
> https://klubnl.pl/wpr/en/index.php/klubnl-pl-grabbers/grabber-4-8270hz/
>
> in the normalised spectrogram the average of relative powers for each 
> timeperiod are normalised to a constant value. so this is something 
> similar to AGC, taking care of day/night noise variations. i think 
> Paul does something similat, because his spectrogram doesn't show 
> differences in day/night noisefloor.
>
> the S/N isn't great, but this is from a simple e-field antenna in the 
> middle of the city.
>
> i've also added a 6470Hz grabber for your next tests (and will add 
> 5170Hz and normalized graphs in the future):
>
> https://klubnl.pl/wpr/en/index.php/klubnl-pl-grabbers/grabber-sq5bpf-6470hz/ 
>
>
> VY 73
>
> Jacek / SQ5BPF