Re: Nobody on 10GHz? Work yourself on JT9 via WebSDR

Neil Smith G4DBN

We can dream...

Hi Ben, my CW signal was so weak, it was right at the edge of perception. It might have worked using *extremely* long dots, perhaps 3 seconds, or maybe even longer, and displaying the result on a waterfall, but using the slow and wide tones of this mode spreads out the transmission of "CW G4DBN IO93" over 50 seconds, and adds in some redundancy and error detection. No magic, and not much technology other than a thing to generate the tone sequence, and another thing to detect the tones and turn the sequence back into plain text.  The beauty of it is that if some of the tones are missing or messed up, there is still enough left to reconstruct the original message.  It does it better than human ears because it effectively works in much narrower bandwidths than you could manage with a CW filter.  It's huge fun as well, although not *quite* as rewarding as digging out a weak CW signal from under the noise.  Thing is though, it would still have managed to drag out the signal if it had been quite a bit weaker, whereas my ears just couldn't manage it.

I wish more microwavers had digital modes available, it makes contacts possible even under very unpromising conditions and adds a dimension.

Huge thanks to the teams who make the WebSDRs possible. I use the Eindhoven, Farnham and Mow Cop systems quite a lot in the dark reaches of the night when sensible microwavers are safely tucked up in bed.

Neil G4DBN

On 15/03/2020 10:47, militaryoperator via Groups.Io wrote:

Thanks Andy but far too old and too much going on to start learning about these digital modes, happy with a microphone!! or Morse key.

cheers, Ben.

On Sun, 15 Mar 2020 at 09:34, militaryoperator via Groups.Io <> wrote:
Whats JT9G and WSJT-X ? are these rare stations? 


-----Original Message-----
From: Neil Smith G4DBN <neil@...>
To: <>
Sent: Sat, 14 Mar 2020 23:16
Subject: [UKMicrowaves] Nobody on 10GHz? Work yourself on JT9 via WebSDR

The path to Mow Cop WebSDR is just about viable at the moment with the 10GHz dish rather low, so I sent some traffic to it on 10368.890 using JT9G with a 1200Hz base tone and recorded the WebSDR output to a file. Replayed the recorded audio via a virtual audio cable into WSJT-X and it decoded with a nice -16dB report.
Silly things to do on a blustery Saturday night in Yorkshire.
Neil G4DBN

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