Message-ID: <3A52FE1D16D94F5ABE4790254BDD2503@gnat>
From: "Alan Melia" <alan.melia@btinternet.com>
To: <rsgb_lf_group@blacksheep.org>
References: <CAL-VeeOzV2P6FQeiauSS=zC-1wt40kD8CbMswNyywtp+9-v99Q@mail.gmail.com> <7BEFCE23-3244-45F0-979D-2EA0777850F1@md.metrocast.net> <5ADEEF82.6030607@posteo.de> <5AE0449E.9070606@posteo.de> <5AE06CD9.7000809@posteo.de> <5AE0DF9D.9050106@posteo.de> <5AE867D9.9090706@posteo.de> <5c9b9570-015c-224c-a2ca-68d79fc650cc@abelian.org> <5AEAD6DD.7010804@posteo.de>
Date: Thu, 3 May 2018 11:11:20 +0100
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Subject: Re: ULF: A new band is opened up! 191 km | DL0AO results
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Hi Stefan I think it is possible. I was sent a trace on 136kHz a few years 
back by Peter df3lp (I think) of Lakihegy HGA22 received with an intense 
lightning storm at about the path mid point.

There were strong increases in strength of about 8 to 10dB on the trace 
decaying over a period of minutes. Unfortunately I cannot now find the 
picture in my archive (sloppy filing) I suppose its possible Peter still has 
it. So it would seem there is the possibility of lightning strkes injecting 
charge into the ionosphere.

Alan
G3NYK
----- Original Message ----- 
From: "DK7FC" <selberdenken@posteo.de>
To: <rsgb_lf_group@blacksheep.org>
Sent: Thursday, May 03, 2018 10:31 AM
Subject: Re: ULF: A new band is opened up! 191 km | DL0AO results


> Paul, ULF,
>
> There is an interesting unexpected observation: In the night of the
> 30th, there were strong thunderstorms all over Germany. The noise was
> very high of course. But when analysing the carrier for that single day
> (from the DL0AO data file), i'm getting a peak SNR of 10.98 dB for a 10
> hour carrier starting 01:20 UTC. A 6 hour carrier starting at the same
> time produces a similar SNR. That peak is the strongest in 5000 bins.
> SNR plot attached. I easily decoded a '*' message with good Eb/N0 and no
> false decodes.
>
> I had serious doubts but then Markus got similar results with his
> totally different way of data analysis.
>
> Can this be real? Could it be propagation? Could it be that the
> lightnings have an effect on the ionosphere to improve reflection
> significantly so that this S/N can be reached? You know that 191 km wave
> is at about lambda/2 at the height of the ionosphere relative to ground
> (at night).
>
> We need more such data. The carrier is now running for more than 1 week
> without an interruption and it will continue further... Oh and we need
> more thunderstorms on the path! :-)
>
> It would be most interesting to see if you're getting similar results
> from the data of DL4YHF, which is a different and longer path.
>
> Another thought: I choose 1.57 kHz because this is below that 'cut-off'
> frequency for distant sferic propagation (the distant sferic S/N drops
> by say 20 dB at 1.6 kHz at night), so the night QRN is much lower there.
> BUT, maybe it would be even better to transmit directly on that cut-off
> frequency, i.e. between 1.6...1.65 kHz?! No problem to move to that
> frequency but let's collect more data on 1570.01 Hz for the next weeks.
> Looks like an ideal summer experiment!
>
> 73, Stefan
>
>
> Am 01.05.2018 15:29, schrieb Paul Nicholson:
>>
>> So far, nothing at Todmorden, by stacking all the daytime
>> signals, or by chaining them for super narrow bandwidth.
>>
>> Some problems using Bielefeld vlf6, the stream often
>> steps backwards one sample at a time and I'm not sure
>> where that leaves the phase.
>>
>> -- 
>> Paul Nicholson
>> -- 
>>
>