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Date: Fri, 06 May 2016 11:30:01 +0200
From: DK7FC <selberdenken@posteo.de>
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Subject: Re: VLF: EbNaut transmissions on lower frequencies?, pre-tests: 6.47kHz
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Hello Paul, VLF,

Am 06.05.2016 02:24, schrieb Paul Nicholson:
>
> Stefan,
>
> Your 200mA carrier comes through well here at 6.47 kHz, nice
> signal at 0.14 fT during the night.
That is very nice. Can you show a graph showing a spectrum peak with 
noise and signal in a reasonable bandwidth?

I'm very happy with my VLF remote grabber, have been impressed by the 
low man made noise levels above 5 kHz. The diurnal QRN is much lower on 
6.47 relative to 8.27. I hope this can be an advantage.
Yesterday i have been on the tree, completing the installation of the 
E-W single turn loop which is now used.
> Daytime is 0.04 fT or
> below and might be a bit of a struggle.
Oh, such a difference. What could be the reason, propagation? What 
day/night ration can be found on 8.27?
It would be interesting to get the information which band is 'better', 
when assuming a current limited TX system. On 8.27 kHz the ERP will be 
2.1 dB higher then on 6.47 kHz. But maybe the phase stability and 
diurnal propagation (in a range below 2000km) will be better on 6.47 
kHz. On the other side, the average RX system will have a higher man 
made noise level there.
>
> I don't need any more carrier.  From the raw recording I can
> optimise filters and blankers and look at most of the diurnal.
OK, i'm looking forward to your EbNaut decodes of my two transmissions 
:-) With 0.14 fT there is a real chance i think. As i know you, i think 
you want to wait with the presentations of your decodes until you've 
found the best filter+blanker settings to get the best SNR possible.

My next goal is of course the 58 km band, 5.17 kHz, where i have been 
active just 2 times ( i think) in 2010/2011. Then, i will go lower for 
the first time. New land!

73, Stefan
>
> -- 
> Paul Nicholson
> -- 
>