
Notes on HamComm:                                            Dec.4th 1990


- HamComm is a program for ham radio communications.  In its current
  experimental state it supports reception and transmission of amateur
  radio teletype signals.  The interesting thing about it is, that it
  doesn't require a modem.  The audio output of the transceiver is
  connected to the serial port of any PC/XT/AT compatible computer thru a
  very simple and low-cost circuit.  You need only one ic (op-amp LM741)
  and a few diodes, capacitors and resistors.  For transmission the
  speaker output is connected to the microphone input of the transceiver
  thru a passive r/c filter.  Audio frequency decoding and serial/parallel
  conversion is all done by the program. 

- HamComm will automatically detect the type of video adapter in use.
  MDA, CGA, EGA, VGA and Hercules are supported.  All graphics routines
  are written in assembler for speed.  The graphics display functions
  are not available on MDAs since the MDA has no graphics mode. 
  No attempt has been made to avoid screen flicker (snow) on cheap CGAs.

- HamComm will run on XT maschines but the graphics displays of the input
  signal are more fun to watch on an AT-class maschine.  Nearly all of the
  functions can also be controlled by using a mouse.  A harddisk is not
  required.  All texts are written in english and the online help function
  includes the schematics for the interface circuit.  There are also
  predefined standard phrases and a qth distance/direction calculator.

- The converter schematics are included in the online help texts.
   1. Start the program.
   2. Hit F1 to start the help subsystem.
   3. Hit the letter 'O' to select topic 'Overview'.
   4. Hit the TAB key to select topic 'Converter' and hit return.
   5. Scroll the help text using the cursor-up/cursor-down keys
      and read the text.

- While the 'TUNE' display is active the center frequency can be abjusted
  using the 'Cursor-Left' and 'Cursor-Right' keys.  The 'Home' key will
  reset the center frequency to the standard value of 700Hz.  
  These adjustments can also be made using the mouse. 

- While the 'RTTY' display is active the 'AutoLetter' feature can be 
  switched on and off using the control-L key. The default state is 'ON'.
  In 'AutoLetter' mode HamComm will automatically switch from figures to
  letters after five characters. 'AutoLetter' will also advance to the
  beginning of the next line on reception of a 'carriage return' character
  to avoid overwriting of previously received text.

- While the 'RTTY' display is active normal text can be typed in the 
  TX window. If the cursor reaches the end of the line the last word will
  wrap around to the next line.

  !                                                                !
  !  A line of text is moved to the transmit buffer when:          !
  !                                                                !
  !     1. a character is typed in the last position of a line or  !
  !                                                                !
  !     2. the 'Enter' key is hit.                                 !
  !                                                                !

  Several keys have special meanings:

     - cursor-left, cursor-right, cursor-up, cursor-down:
                  move TX window cursor.

     - control-A: go to beginnig of line

     - control-E: go to end of line

     -      Home: go to first line

     -       End: go to last line

     -     Enter: send the current line to the TX buffer.

     -    Insert: toggle insert mode

     - control-PgUp, control-PgDown:
                  resize RX/TX window

     - control-Home, control-End:
                  roll back RX window


- The SPECTRUM function is a graphical display of the audio frequency as
  detected by HamComm.  Please keep in mind that this is not the real
  audio spectrum.  This program is not a substitute for a 10000$ spectrum
  analyzer.  Some newer XTs may be fast enough to maintain a rapidly
  changing display but it's much more fun to watch this on an AT-Class
  maschine with color monitor. 

  The display scale can be changed using the keys Page-Up, Page-Down,
  Cursor-Left, Cursor-Right and HOME. Hit the spacebar to reset all
  frequency counters to zero.

- Option '-l43' on the commandline will switch to 43 line ega mode.

- Option '-l50' on the commandline will switch to 50 line vga mode.

- The author can be reached via the packet radio mailbox system.
  Send your error reports and other comments to DL5YEC @ DB0BQ.

- Special thanks go to OM Winfried, DL1YCE, for contribution of the
  QTH locator routines and many helpful suggestions.


73 es 55 de django dl5yec
