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=?UTF-8?Q?Re=3A__=5Bamsat-bb=5D_D700_TNC_Calibrate_mode_etc_=28II=29?=



   I have now read the TAPR modem documentation
   (ftp://ftp.tapr.org/info/kits/manuals/9600_modem_man.pdf) but I still
   have many questions.
   1) Where are the standards that allow the TAPR modem to talk to any
   other 9600 FSK modem?  How did the designers know what to do?
   2) Like what frequency deviation? I can pick anywhere from 1 to 64kHz.
   3) If the transitions are filtered, will different modems with
   different filters still talk to each other?
   4) What scrambling polynomial is being used?  TAPR manual tells me a
   17bit one, but which tap bit?  Is it 12 like in the g3ruh modem
   (http://www.amsat.org/amsat/articles/g3ruh/109/fig03.gif) or 5 like in
   the KD2BD modem
   (http://www.amsat.org/amsat/articles/kd2bd/9k6modem/fig1.gif)?
   5) Can an FSK modem interface to a GMSK modem?  How can one tell what
   kind of modulation a modem is doing?
   My interest here is more broad than just the D700, I just happen to
   have that one and know its been used to work satellites in the past.
   What I really want is to standardize my link so that it works with the
   largest number of ham hardware as possible.  What is the most common,
   high quality, FSK modem used for satellites by hams?
   Thanks everyone,
   ~Danny KE7DHQ
      ~~~~~~~~~~~~~~~~~~~~~~~~
      Space Science and Engineering Laboratory
      Montana State University
     Bozeman, MT
   -----Original Message-----
   From: "Sanford, Fred" <fred.sanford@ips.invensys.com>
   Sent 6/3/2006 6:49:43 PM
   To: "'Danny Jacobs'" <jacobs@physics.montana.edu>
   Subject: RE: [amsat-bb] D700 TNC Calibrate mode etc (II)

   The D700 9600 is compatiable (not sure if generated using the same
   method as) with the 9600 bps modem kits that TAPR used to offer. You
   should be able to find information on the TAPR web page, try starting
   at http://www.tapr.org/pub_9600.html .  If this does not help, let me
   know and I will try help you.

   73 - ka1cqd

   -----Original Message-----
   From: owner-AMSAT-BB@amsat.org [mailto:owner-AMSAT-BB@amsat.org] On
   Behalf Of Danny Jacobs
   Sent: Saturday, June 03, 2006 1:08 PM
   To: amsat-bb@amsat.org
   Subject: [amsat-bb] D700 TNC Calibrate mode etc (II)

      Is anyone on this list familiar enough with the Kenwood D700 to
      describe exactly what the Calibrate function of the TNC does and/or
      describe exactly how the modulation is done at 9600.
      I am attempting to close a 9600 digital link between the D700 on Tx
   and
      a CC1000 FSK chip radio on Rx.   I have control over many
   demodulation
      settings such as FSK seperation frequency and peak detect in the
   CC1000
      but I dont have much information on the standard Ham FSK modulation
      that I think the D700 is doing in 9600 mode. I can easily close the
      link between two of the chip radios.
      So here are my questions:
      1) Is the D700 doing true FSK in 9600 bps mode?
      2) If it is, what is the seperation between mark and space?
      3) Is a scrambling polynomial being used, (i am trying 17 bit
   register
      with bit 5 as tap)
      4) Is the Calibrat mode in the TNC a scrambled square wave?  Has
   anyone
      gotten this to work?
      5) I have read in several articles oblique references to standards
   for
      FSK links but havent been able to find any.  Where are they?  How do
      different Ham radio manufacturers build radios that can talk to each
      other?
      This is part of a University satellite project. We could use
   matching
      chip radios to talk to our satellite but we want very much to
   provide a
      friendly packet-style ham interface to our operation, however we are
      finding that interfacing to the ham equipment quite difficult.
   Please
      Help!
      ~Danny KE7DHQ
      ~~~~~~~~~~~~~~~~~~~~~~~~
      Space Science and Engineering Laboratory
      Montana State University
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