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Re: [wsjtgroup] WSJT Tutorial & Phantom signal

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  • Joe Taylor
    Hi Dave and all, I m just back from vacation, trying to get caught up on email. I ve read your series of messages on trying to decode both signals in the
    Message 1 of 13 , Sep 3, 2008
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      Hi Dave and all,

      I'm just back from vacation, trying to get caught up on
      email. I've read your series of messages on trying to
      decode both signals in the DL7UAE file, and the several
      responses. It seems that you have it all figured out by now
      ... but just in case, the essential points are these:

      1. Since it's going to be a Deep Search decode, you need to
      have Deep Search enabled. In earlier versions of WSJT this
      was true with the default setup; more recently (since
      v5.9.5, as I recall) it has been OFF by default.

      2. Again, since it's going to be a Deep Search decode, of
      course you must have "My Call" set to K1JT. (If you don't
      understand how DS works, you should read
      http://physics.princeton.edu/pulsar/K1JT/JT65.pdf .) This
      is precisely why Step #1 of the Tutorial says:

      "1. If you have already installed and used a version of
      WSJT6, delete your WSJT.INI file or temporarily rename it to
      something else. This will ensure that you start the tutorial
      with everything in the default configuration."

      As for your results of playing with the sample-rate
      correction factor: as you understood, the factor should be
      1.0000 when doing the Tutorial, because the sample files
      were recorded on a system without any sample-rate error.

      The SP6GWB signal happens to be very close to the threshold
      of decodability with the KV encoder. In such a situation,
      small tweaks of anything that affects the sync process can
      sometimes make the difference between decode and no decode.
      You found a tweak that works in this particular case, but
      it won't be useful in general because it depends on details
      of the random noise in this particular file.

      Hope this helps!

      -- 73, Joe, K1JT

      Dave Miller wrote:
      > Has anyone ever tried to decode the "hidden" signal in the DL7UAE file
      > under the JT65B folder of the WSJT samples download. The WSJT6 User
      > manual's tutorial (page 9) says that you should be able to decode a
      > second station (SP6GWB) just 22 hz away from the primary signal
      > (DL7UAE). I have followed the tutorial step by step dozens of times
      > with Versions 4.9, 5.9, and the 7.0 beta and all yield the same
      > results; no SP6GWB signal, only the DL7UAE signal is decoded. When I
      > follow the directions I do get a header line with a * or a #
      > terminator, but nothing to the right but blank space. Has anyone else
      > successfully decoded this second signal? I am trying to learn the ins
      > and outs of this program before I get on the air and mess up a QSO.
      > Dave N9SS EN50
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