Re: soundmodem on 2.4-kernel

From: Tomi Manninen OH2BNS (obfe.hiybcslyw@kerailya.tunkki.fi)
Date: Wed Jun 13 2001 - 13:47:25 EEST

  • Next message: Joe Martine, N5USR: "Usermode soundmodem"

    On Wed, 13 Jun 2001, Tomi Manninen OH2BNS wrote:

    > > The upstairs box doesn't trigger on the the tune tones of the
    > > downstairs box so it can't receive anything. I can see the downstairs
    > > machine transmitting in the o-scope window but it doesn't trigger.
    > > The downstairs machine, on the other hand, can hear the upstairs machine.
    > > It typically indicates tune tones of +/- 0.2 Hz
    >
    > That means it is able to hear the tune tones long enough and to make a
    > "tuning decision". So that rules out any tx-delay problem. Not that there
    > would be a tx-delay to set in newqpsk... :-)

    Ouch. It seems I was a bit careless in reading what you wrote above...

    If your rig is really bad then a "tx-delay" problem might explain the
    behaviour at the upstairs box. The default tune preamble is 32 symbols
    (384ms) and the receiver needs minimum of 16 symbols (192ms) to make a
    tune decision. That leaves 192ms for the downstairs TX to stabilize. You
    can make the tune preamble longer by editing the line

      #define TxTuneLen 32

    in newqpsk/modemconfig.h.

    Anyway this doesn't explain the downstairs box problems. 

    -- 
Tomi Manninen           Internet:  zvhrlaw.grsac@rele.tunk.net
OH2BNS                  AX.25:     terhi.victor@logonet.com
KP20ME04                Amprnet:   gakzneo@anticlockwise.com

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