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Date: Sat, 14 Dec 2013 19:46 +0000 (GMT Standard Time)
From: tsmithers@cix.co.uk (Trevor Smithers)
To: markusvester@aol.com, rsgb_lf_group@blacksheep.org
CC: tsmithers@cix.co.uk
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Message-Id: <memo.20131214194626.4172B@Jodan.cix.co.uk>
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Subject: Re: LF: All 73 Banders... wspr-x recordings
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Status: O

Hi Marcus, Hartmut, Victor

It doesn't have to be from last night - I'm sure Joe would be happy to see any recordings that 
you think would benefit from further analysis.

With not many stations using wspr-15 on a regular basis any feedback he gets is going to be 
limited, so anything that demonstrates the qrm conditions in EU is going to be useful.

73
Trevor  G0KTN

-------- Original Message --------

Trevor,

thanks for this comment! It would be interesting to know how much =
spacing is needed between a weak WSPR signal and a relatively strong =
neighbouring carrier, located within the WSPR analysis range but outside =
the four-tone spectrum of the desired signal.

Unfortunately I can't contribute as I hadn't run recordings, and also =
both the desired WSPR signal and the Loran carrier were anyway too weak =
here for a meaningful result. Perhaps Hartmut or Victor happened to have =
.c2 or .wav saving enabled last night?=20

Best 73,
Markus

From: Trevor Smithers=20
Sent: Saturday, December 14, 2013 6:43 PM
To: markusvester@aol.com ; rsgb_lf_group@blacksheep.org ; =
lowfer@mailman.qth.net=20
Cc: tsmithers@cix.co.uk=20
Subject: Re: LF: All 73 Banders...


As you know WSPR-X is regarded as experimental software and as such Joe =
Taylor K1JT has=20
often asked for users to contact him with any difficulties they =
encounter.

So how about Marcus, Hartmut, Victor and anyone else, producing a .wav =
file of successful and=20
non successful wspr-15 decodes including all the DCF77 and other qrm. =
The files could be sent=20
to Joe direct or made available for him to download and he can analyse =
them to see if any=20
improvements can be made.

K1JT email address can be found at the bottom of this page
http://physics.princeton.edu/pulsar/K1JT/wspr.html

Trevor  G0KTN


From: Markus Vester=20
Sent: Saturday, December 14, 2013 4:03 PM
To: rsgb_lf_group@blacksheep.org ; Bob Raide=20
Subject: Re: LF: All 73 Banders...
...
It's however strange that Hartmut and Victor didn't get any decodes, =
even though the signal seemed to be well visible for both. What looks =
like noise on Victor's capture must really be the WSPR-15 spectrum:=20
 =
http://dl.dropboxusercontent.com/u/26404526/pa3fny_74603_131214_0700_arro=
wheads.jpg

But both statiopns have a relatively strong Loran line, and Hartmut's =
directional antenna is pointing towards Sylt. However the nearby line =
frequency 74603.280 Hz should have been well outside the occupied =
spectrum of Bob's WSPR signal (74603.51 to 604.24), so it's not ovbvious =
why it should have prevented decodes. I'm speculating that the WSPR =
software finds the strong line, tries to sync to it, and then somehow =
excludes nearby real signals from further decode attempts. To prove the =
point and see how much spacing is needed, we could experiment with =
letting WSPR decode local audio signals in the presence of injected =
carriers. But systematic trials with WSPR tend to be time-consuming, =
even if such tests were accelerated by scaling to WSPR-2.
...