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2550Re: [wsjtgroup] WSJT 5.8.6 Tone Level Settings, TX/RX Delay

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  • Joe Taylor
    Oct 1, 2005
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      Joe --

      Here are a few quick answers to your questions.

      Joseph A. Counsil wrote:
      > Greetings,
      > I have been using WSJT 5.8.6 the last couple of weeks, having upgraded
      > from 4.9. Joe has done an excellent job of adding new features and
      > integrating the package.
      > There are two things I do not find in the new version which I needed
      > in the old...
      > 1) Tone Level Settings - The old version had an option in the settings
      > to tweak the audio level on each of the four tones. I found with my
      > system that the tones were not all generating equal output from the
      > radio, so was able to improve that by using these settings. With the
      > new version, I don't find that capability anywhere (not even hidden in
      > the configuration file in the WSJT program directory). Am I missing
      > something?

      I decided that those tone adjustment boxes were a bad idea.

      Software solutions to hardware problems are generally "kludges". In
      this particular case, if different tones coming out of the soundcard
      have different amplitudes there will be sharp discontinuities in the
      audio waveform. This will produce out-of-band distortion products.

      One of the advantages of the FSK441 waveform, as designed, is that it
      has constant amplitude and continuous phase. This means that it
      produces less RFI/TVI than SSB or CW (because no amplitude modulation is
      present), and it means that you can use non-linear power amplifiers
      without introducing signal distortion.

      With radios that are just "a bit off", it generally works well to just
      turn up the Tx audio gain (or soundcard output) a bit, letting the
      stronger tone(s) saturate if need be. Because only one tone is present
      at any instant, this will *not* distort your FSK441 signal, or produce
      out-of-band splatter, the way it does with PSK31.

      > 2) TX/RX Delay - The old version had an option to implement an RX
      > delay time before the program would begin acquiring data when
      > switching from TX to RX; and a TX delay time when switching from RX to
      > TX. Again, I find no such option in any settings nor in the
      > configuration file. Am I missing something?
      > I need both of these options to optimally set up my system. My tone
      > levels are several dB unequal, and I have TX/RX transients in my data
      > acquisition.

      I decided to simplify things and make these values fixed. The TxDelay
      is big enough that WSJT will not hot-switch your relays. Is there
      another reason that you need user control here? Are your switching
      transients producing garbage decodes, or something?

      -- 73, Joe, K1JT
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