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1779Re: V4 GUI improvement proposal

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  • la7um
    Sep 6 10:44 AM
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      Rick. Off course. I just wondered how that P3 Picture transfer in one direction worked while some chat (450hz?) came the other way during the acks? It was said to work like that.

      I don't know the GOLD P3 program myself, so I may have got it wrong. SW perhaps only from time to time made some ordinary turnarounds ISS/IRS/ISS.

      Anyway forget about it. I didn't intend squeezing picture through the 200hz channel. Irrelevant to V4 and the genious 200Hz solution.

      The different font issue for helping hams having coulour disabled visual is maybe something to consider down the lane. I don't have that problem myself, so don't really know myself.

      73 Finn/LA7UM

      --- In V4Protocol@yahoogroups.com, "Rick Muething" <rmuething@...> wrote:
      >
      > Finn,
      >
      > Pactor 3 uses 12 x the bandwidth of V4 (2400 Hz vs 200 Hz). You can’t have narrow bandwidth while sending large amounts of data UNLESS you have very high S/N. This goes back to Claude Shannon’s landmark theorem relating theoretical channel capacity (bits/second/Hz) vs. S/N. We are dealing here with HF where S/N is low, sometimes negative and multipath fading is common or severe at times. You simply can’t get the same bits/second/Hz as you do on a land line telephone with a stable channel at 40 dB S/N.
      >
      > Rick KN6KB
      >
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