Date: Sun, 7 Jan 2018 02:23:29 +0100 (CET)
From: Jacek Lipkowski <sq5bpf@lipkowski.org>
To: rsgb lf group <rsgb_lf_group@blacksheep.org>
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Subject: Re: LF: Re: SL settings for QRSS
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Hello Jack,

I'm currently starting to write a short article about using spectrum lab 
for vlf for the klubnl.pl site. Could you tell me what you would like to 
see there? (example SL configs etc). We can take this off-list if you 
want.

This was supposed to be more of an "using Spectrum Lab under linux" 
article, but i can include additional non-linux details if you want. I'm 
sure this might be helpful for more people.

VY 73

Jacek / SQ5BPF


On Sat, 6 Jan 2018, JACK ASKEW wrote:

> Date: Sat, 6 Jan 2018 17:51:17 -0700 (MST)
> From: JACK ASKEW <va7jx@shaw.ca>
> Reply-To: rsgb_lf_group@blacksheep.org
> To: rsgb lf group <rsgb_lf_group@blacksheep.org>
> Subject: Re: LF: Re: SL settings for QRSS
> 
> Hi Wolf,
> 
> SL is ok for just starting out as a beginner using QRSSS, but I can see now why EbNaut
> is far superior, at least you can see text that was sent. Probably a bigger learning curve 
> required to fully understand it though.
> Sadly I was unable to find any configuration files for QRSS for SL on Stefan's QRZ.com site. 
> There is certainly lots of reading material so perhaps I might have missed it.
> 
> Cheers,
> Jack
> 
> _________________________________________________________________________________________________
> From: "Wolfgang Büscher" <dl4yhf@freenet.de>
> To: "rsgb lf group" <rsgb_lf_group@blacksheep.org>
> Sent: Saturday, January 6, 2018 1:59:40 PM
> Subject: LF: Re: SL settings for QRSS
> 
> Hi Jack,
> 
> Yes, it takes several hours until the first spectrum (or line of pixels in the spectrogram)
> appears.
> To load a complete (FFT-) window for 47 uHz bin width, it takes
>    1 / 47 uHz = 21276.x seconds = 5.9 hours .
> That's dictated by the maths. Not related with CPU speed. "Not a bug but a feature" .
> 
> That's one of the reasons why Paul's Ebnaut has completely replaced these ancient "visual" modes
> ;-)
> 
> Cheers,
>   Wolf .
> 
> Am 06.01.2018 um 22:07 schrieb JACK ASKEW:
> 
> Thanks Wolf, lots to read up on, excellent information on learning
> how to use SL for these slower speeds.  Also thanks for
> pointing me to Stefan's site regarding the configuration
> files for QRSSS, I wondered if anyone still had them available.
> I recall playing with SL's ability to use VLF stations to lock onto but
> they were too weak here in Canada. I do have GPS on my Tx now
> but I still see some un-explainable instability over a period of 4-5hrs
> but far less than 0.05Hz...so maybe not an issue when I was using
> file 8270Hz_QRSSS_4mHz.usr. Not sure what equates to in QRSSS
> though. I find that if I try anything like 'VLF_Soundcard_32K_47uHz.USR'
> it takes several hours to load up in SL but I guess that stands to reason...I hope.
> Regards
> Jack Askew
> 
> 
> 
> _________________________________________________________________________________________________
> From: "Wolfgang Büscher" <dl4yhf@freenet.de>
> To: "rsgb lf group" <rsgb_lf_group@blacksheep.org>
> Sent: Saturday, January 6, 2018 10:42:14 AM
> Subject: SL settings for QRSS (was: Re: LF: RE: Todmorden receiver by Jack)
> 
> Hello Jack and all,
> 
> you wrote:
> 
>  >It comes back to using something like SL with its QRSS
> capabilities. I wish I had a good file that worked at 8720kHz
> for QRSS600 as an example. This would be a good start if nothing else.
> <
> 
> It's not that difficult to set up. The key point in SL to get into the
> microhertz-resolution is the decimation (of the sampling rate), along
> with complex frequency to have a complex FFT spanning just a few Hz
> around the "frequency of interest". The effect is similar as a
> super-long FFT (concerning the frequency bin width, and thus the
> "gain"). I think on Stefan (DK7FC's) site you can find some
> configuration files for QRSSS.
> 
> Back in the "old days" of extremely slow Morse, I wrote this short
> how-to (for Spectrum Lab):
> http://www.qsl.net/dl4yhf/speclab/qrss_quickstart.htm
>    (it shows how to pick one of the VLF transmitters to stabilize the
> soundcard's sampling rate,
>    a bit out of fashion since good GPSes with sync output became
> available, but anyway..)
> 
> To make the FFT window even longer / frequency bins even shorter than
> used in the default settings,
> use the option 'complex input for the FFT with internal frequency
> shift', as shown at
> http://www.qsl.net/dl4yhf/speclab/settings.htm#fft_size
> 
> And, last not least, there an explanation of FFT length, decimation,
> windowing functions, resulting resolution / effective receiver bandwidth
> versus dynamic range, etc:
> http://www.qsl.net/dl4yhf/speclab/fftinfo.htm
> 
> All the best,
>   Wolf DL4YHF
> 
> 
> 
> 
>
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