Return to KLUBNL.PL main page

rsgb_lf_group
[Top] [All Lists]

Re: LF: Re: EbNaut test transmission

To: [email protected]
Subject: Re: LF: Re: EbNaut test transmission
From: Markus Vester <[email protected]>
Date: Tue, 17 Nov 2015 13:08:50 -0500
Dkim-signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=mx.aol.com; s=20150623; t=1447783730; bh=sYxXWXpCRPRHH/qc9/Bxyobl8mxTbk2AFf3xMeqDMn4=; h=From:To:Subject:Message-Id:Date:MIME-Version:Content-Type; b=02G1OkO1fiMbC0MBZZaHt88g7u3uU7l7OAGPPV5lVvbOTRDW7oBH3knBrHaVnWWS+ Hc7+LoyGcsGGL62XyikE1Bzm38Ax+AmkU8TP1eiUeigpEJ8suuDj15CYD+bWxWMdiM Ircp/v+kFehsc5O3KodvEc+Fg1e2wgLFfA7Omaio=
In-reply-to: <[email protected]>
References: <[email protected]>
Reply-to: [email protected]
Sender: [email protected]
...oops sorry, this is the correct attachment.

73, Markus
-----Ursprüngliche Mitteilung-----
Von: Markus Vester <[email protected]>
An: rsgb_lf_group <[email protected]>
Verschickt: Di, 17 Nov 2015 6:54 pm
Betreff: Re: LF: Re: EbNaut test transmission

Andy,
 
getting even better... 56/704 symbol errors and 11.2 dB Eb/N0 for the 16:30 message.
 
I'm sure that Domenico will be able to pick up the signal in South Italy. Would anyone in TA-land want to attempt a decode tonight?
 
For receiving with SpecLab, you could use the opds-spectrum-export and IFFT method, as described in my post to blacksheep on Sep 27th (I could repost if required).
 
73, Markus
 
 
-----Ursprüngliche Mitteilung-----
Von: Markus Vester <[email protected]>
An: rsgb_lf_group <[email protected]>; rsgb_lf_group <[email protected]>
Verschickt: Di, 17 Nov 2015 5:59 pm
Betreff: Re: LF: Re: EbNaut test transmission

Well done Andy!
 
This decode was from a message before the NTP adjust. Your transmit frequency looks stable and accurate.
 
I have temporarily moved the opds SpecLab instance to your frequency, and inverse Fourier transformed a saved opds spectrum data file.
 
Domenico and I have successfully tried speeds up to 0.1 second symbols, with no additional tweaking after we'd once got the time offset right.
 
Best 73,
Markus (DF6NM)
-----Ursprüngliche Mitteilung-----
Von: Andy Talbot <[email protected]>
An: rsgb_lf_group <[email protected]>; rsgb_lf_group <[email protected]>
Verschickt: Di, 17 Nov 2015 5:26 pm
Betreff: LF: Re: EbNaut test transmission

Its still going.
At 1611z I ran rsNTP and it made a PC clock adjustment of 0.4 seconds, which with the 0.5s symbols used for this transmission will glitch slightly .

Pleased to note that a local recording I made using the  new LF Receiver hardware and my own software to generate a .WAV file compatible with Spectrum Lab's did generate a valid decode. Recorded at fs = 31.25Hz  That was before the PC time had been corrected and I had to do a fair bit of shuffling with the Start Offset value to get a decode.   Values from 0.45s to 0.85s worked - much of that presumably due to the PC time offset in the transmission.   But once a value in that range had been entered, zero decode errors - which is what one would expect of a very strong local copy !

It does appear that using EbNaut with rates much faster that 2S/s could end up very fraught with timing offsets.  Fortunately, weak signalling with longer symbols of several seconds will have less of a problem with timing offsets.

Andy  G4JNT


Attachment: 11171646-log.txt
Description: Text document

<Prev in Thread] Current Thread [Next in Thread>