[aprssig] UZ7HO Soundmodem Updated Again - QPSK Modes Added

Stephen H. Smith wa8lmf2 at aol.com
Sat Apr 18 08:18:59 CDT 2015

[18 April 2015]

Another update to the UZ7HO Soundmodem soundcard software TNC was released 
today.    The latest version .81 has added QPSK modes at 2400, 3600 and 4800 baud.

These modes use audio subcarriers just like the conventional 300 and 1200 baud 
packet.  As a result, these faster modes can be used through the usual 
sound-card-interface & mic jack or dataport connection.  (Unlike the G3RUH 9600 
baud mode that requires direct DC connections to the transmitter modulator and 
receiver discriminator.)   Note that these new faster modes will work with most 
FM radios, but may be problematic with HF/SSB transceivers due to the limited 
bandwidth of the typical SSB transmit filter (only about 2.2-2.4 KHz).

With these latest versions, the Soundmodem can now transmit and receive AX.25 
packet on:

-  Classic 300, 600 or 1200 Hz baud FSK

-  300, 600, 1200 and 2400 baud BPSK

-  2400, 3600 and 4800 baud QPSK

This makes the Soundmodem an exceptionally versatile "soft TNC" directly usable 
by UIview, APRSis32, APRSpoint, APRSplus or any other client that can provide 
an AGWpe-type interface to a soundcard TNC.   Looks like plenty of food for 
experimentation comparing the relative performance of these different modes.

As usual,  I have repacked UZ7HO's original zip file distribution into a full 
Windows "wizard"-type  .EXE  installer.   Download it from my website at:

.   <http://wa8lmf.net/miscinfo/#UZ7HO>

=========== CHANGE LOG ===============

SoundModem v0.81b changes:
- Added QPSK 2400, 3600 and 4800 baud modes.

SoundModem v0.80b changes:
- Added new BPSK 2400 baud modem.
- Little code optimization.
- Fixed some minor bugs.

SCM v0.78b changes:
- Added new BPSK 300-1200 baud modes.
- Reduced CPU load.

SCM v0.72b changes:
- Added the KISS ACKMODE support.

SCM v0.71b changes:
- Fixed "Frame Collector" operation with MAXFRAME greater than 4 and IPOLL
   frames. By default it supports up to 6 frames into collector's buffer now.
- Added "TXFrmMode" option (that was available in 9k6/19k2 version). It allows
   to select the transmission mode of the frames.

   If set "TXFrmMode=1" then it will repeat only one frame on each of REJ acks.
   It can be useful in poor condition jointly with MAXFRAME up to 4. If another
   station uses a TNC which can operate with "Frame Collector" this option can
   improve a performance, especially on HF.

   If set "TXFrmMode=0" then it will always repeat the block of the frames, of
   which the number is limited by MAXFRAME. It can improve the efficiency in
   good condition. Especially with TNCs without "Frame Collector" function.

   By default this value is "1".

SCM v0.69b changes:
- Improved DCD reaction on the AX.25 flags and zeros stream.
- Changed default filters settings for the modems.
- Added KISS TCP-Server
- Added KISS Optimization
- Added transcription of NETROM and IP traffic in the monitor window.
- Added some changes in L2 protocol.
- Added IPOLL frames.
- Fixed RNR frames processing.
- Fixed waterfall bug under Linux (WINE).
- Fixed some inessential errors.

G3RUH SCM v0.16b changes:
- Reduced CPU load.
- Changed samplerate to 48000 by default.
- Added 19200 baud G3RUH modem.
- Added some features from latest SCM version.
- Added "Non-AX25 filter" option. It blocks non-AX25 traffic through AGW interface

SCM v0.57b changes:
- Reduced CPU load.
- Added option that disable waterfall in minimized state.
- Added option of the application priority that improves the work of the modem
   during peaks of CPU load (decreased gaps and stuttering sound during 

SCM v0.52b changes:
- Improved MEM-recovery feature. That tries to recover corrupted frame from
   the last frames buffer. It may help if the frames are often repeated, e.g.
   supervisory frames. You can change the number of last packets in the INI file
   (by default is "MEMRecovery=100"). Higher value may help on a very noisy path.

   If you don't need to receive the short non-AX25 frames you can limit minimal
   length of frame to 17 ("RawPktMinLen=17"). It will reduce the accumulation of
   unnecessary frames in the buffer.

SCM v0.51b changes:
- Limited the number of bits for bit recovery operation (only for undefined
   state at three different levels of threshold comparator).
   WARNING! Test showed this option may cause additional erroneous CRC collisions,
   so use it at your own risk. By default is OFF

SCM v0.50b changes:
- Added single bit recovery feature
- Fixed transmission non-AX.25 frames to application (see option "NonAX25Frm"
   in the INI file)

Stephen H. Smith    wa8lmf (at) aol.com
Skype:        WA8LMF
EchoLink:  Node #  14400  [Think bottom of the 2-meter band]
Home Page:          http://wa8lmf.net

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