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969Re: [wsjtgroup] RH 4/3 Modes

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  • Catharinus PE1AHX in JO21OS
    Apr 3, 2004
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      Hi Tip,

      here in Europe we have done some more (but still limited) testing on 144MHz
      with the 441A, 441B & 441C modes. This is made easier because of the high
      MS activity (several hundred stations within 1000 mile radius). This high
      level of activity also makes it more difficult to 'just use' the new modes
      on the calling frequency (144.370) because of the confusion that generates.

      This means most tests have been done on sked. The results (my personal
      ones as well as derived from comments on the 144MHz chat
      http://www.on4kst.com/chat/start.php ) is that FSK441C is definitely to
      slow for the shorter bursts as they occur very frequently during sporadic
      meteors. A 40ms burst becaomes useless.

      FSK441B suffers a lot less from the slowdown (only 23% or 4 characters
      decoded becomes 3) but the slowdown on short bursts is still
      noticable. The main 'advantage' of 441B - the error correction - does not
      show in real world testing. Many of us have not seen an improvement in
      accuracy or seen easier completion when using 441B over 441A. It appears
      that the higher speed of 441A together with the 'visual' filtering (or
      error correction) still generates the fastest QSO's with the least amount
      of errors.

      While saying this I must emphasize that we Europeans do NOT use Single Tone
      or Short Hand messages since these are to error prone. It may well be that
      441B or C in those situations works better. The problem with ST is that
      any birdie can result in a 'valid' report so error correction may well help
      that situation.

      For now - other than the occasional exception - all QSO's are (still) made
      in FSK441A since it works best for us.

      If any of you want to discuss this real-time you can often find me on the
      ON4KST chat together with many other enthousiasts.

      73 & gd rocks!
      Catharinus PE1AHX JO21os

      At 15:43 02-04-2004 -0600, you wrote:
      >Just a friendly reminder that starting tomorrow for the Random Hours the
      >modes are FSK441B for 144 MHz and FSK441C for 50MHz.
      >The change was implemented in the Group Announcements and I think Bruce
      >made mention of it last week. I have made numerous contacts using
      >FSK441C on six meters & have found the slower speed decodes much better
      >than the older mode A. My experience with FSK441B on two meters has been
      >limited so we are looking forward to see how it does during the activity
      >It would be nice to see some good rocks for the two meter session. Don't
      >forget to look for the guys out west if you're within range of Arizona
      >and New Mexico. It has been encouraging to see some new activity out in
      >the West! I believe now that three stations have qualified for the
      >"Random QSO Award"; good luck & good rocks.
      >Now if this weather would clear up.
      >To unsubscribe, send an email to:
      >Activity Periods http://www.qsl.net/wa5ufh/WSJTGROUP/WSJTGROUP.htm
      >Yahoo! Groups Links
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