This program will allow you to receive (in conjunction with a shortwave receiver) FAX transmissions. There are many sources of FAX that can be received, from radio amateurs to news services to weather.
    The most prevalent and strongest transmissions are weather charts by the U.S. Navy.
    To use the program, you must own a 512k Coco 3 and a shortwave receiver capable of SSB (single side band) or CW morse code)reception. The unit must be very stable both in frequency and BFO generation. Older units that drift will work but may yield distorted images even when constantly adjusted.
    Connect the radio to your Coco  using  the  cassette cable. The black input plug should be connected to the headphone or audio out of the radio. Tune the radio to a FAX transmission in the USB (upper side band) mode. This can be done best from within the program with the SOUND option active. This option should also be used to ensure that the Coco has not been overloaded. Adjust the radio volume for clear tones. Distortion indicates the radio volume should be decreased.

1) Select the sound option from the command level.
2) Joystick will be disabled while sound is active.
3) Use button #1 to disable sound and reactivate joystick.

    Adjust the BFO so that the program's tuning indicator stays inside the end markers. If the tone is too far outside the markers the indicator will not be active. Between  transmissions, a steady pure tone should be heard. On USB this corresponds to the high marker; on LSB to the low marker. FAX usually is received USB but if this  yields charts that are mostly black (color inversion) or if there is
excessive interference, try LSB for the problem frequency.
    Once a station is tuned in, select the reception  rate; 120 LPM typical. Program timing is critical for proper reception. If the image drifts slowly across the screen during reception, it may be necessary to adjust the fine tuning constants indicated in the Basic program.
    Do not make large changes; +-1 or 2 is usually enough.

    IMPORTANT: The key to good image  reception  is  a  good  outdoor antenna. A whip or short lengths of wire can work but probably will be very noisy.
    All functions of the main program are controlled using a two button joy stick connected to the right port. Position the cursor for the desired action and push button 1 to activate. Disk I/O requires multiple selection for activation.

1) Select USB (default) or LSB to set program parameters.
2) CLEAR the screen if desired; advisable.
3) Select 60, 90, or 120 LPM.
4) Set the joystick to the bottom central position. Off center images can be shifted by left or right movements of the joystick.
5) To halt reception, center joystick; joystick full down to restart.
6) To restart image capture at any time, push joystick to full up center position; hold several seconds; push joystick full down and in center. Old image will be over written.
7) To end reception, push button #1. Reception will automatically stop when the picture buffer is full. Sound will be on with slight distortion during image capture

    Properly centered images will require receiving the beginning of the transmission. Adjust the short bar to the full left on the screen. With very clean signals, push button 2 which will bring the bar into view. Final adjustments are made with left/right action of the joystick.
 

1) Joystick full up position; centered.
2) With clean signals hold button #2 several (5) seconds.
3) Joystick left to move bar to edge of screen.
4) Center joystick and move to full down position.

    The image will be viewed by pushing J.S. button #1 from the command level while the cursor is not positioned for action or immediately after reception. The full image is equivalent to 60(6x10)PMODE4 screens.
    Movement of the joystick will cause the screen to pan over the full image. The default mode is a wide (640/225) screen for maximum image display. A press of J.S. button #2 will toggle between this screen and a smaller screen (256/225) for more accurate images of 1/1 aspect ratio which don't compress the image on the horizontal axis.
    Press J.S. button #1 to return to the command screen. The image may be viewed as often as desired until a new image is received.
    The image can be reversed in color from the command screen as often as desired.
 
 

    One full image buffer (16 minutes of data)requires a full 40 track double sided disk. If your drive is not double sided, you can't save more than the first half of the image.
    The loader program will adjust your Coco to enable 40 track DSKINI operations. For fastest and smoothest disk I/O, use a step rate of 2; ie. DSKINI1,2 and DSKINI2,2
    Be sure to format enough disks for a session. It is not possible to format disks from within the main program.If necessary it is possible to leave the program (use the RESET  button), format some disks and restart FAX. Most of the image will remain in memory, but the last few minutes will be lost.

1) Select the desired function from the command level with
 joystick.

    It is possible to view any picture disk without losing  much of the current image or loading the entire disk. Some current image loss may occur from the end of large (15 minute) images.
 

1) Select VIEW mode.
2) Select the row to view; 1 - C
3) Pan over image slice with joystick; limited to horizontal.
4) Press button #1 to leave function.

    CC3FAX allows dot matrix printing of the received images. Use the CONFIG program on this disk to select an appropriate print driver. This only needs to be done once as CC3FAX will be altered.
    Select the section of image to be printed from the command
level. Final image with strips taped together has 1536H resolution.
    If you write your own assembly routine, it should load at $1800. REQUESTS FOR CUSTOM DRIVERS must be accompanied by a  COMPLETE LIST of control codes and graphic printhead footprint data.
 
 

    It is inevitable that there will be some noise in the received image. CC3FAX provides two levels (low/high) of  noise removal using IMAGE. The low level removal should be used with pictures that contain fine detail and little noise. Minimal loss of fine detail will occure.
    For images containing large amounts of noise and little fine detail, high level filtering will remove almost all noise.
    The filtering process may be repeated any number of times  for additional cleanup. Time required for one pass over a 15 minute long picture is 5 minutes.
    Please make a disk save of your picture before experimenting with IMAGE as the process is a destructive one.

1) Click on IMAGE
2) Then click on L for low level or H for high level filtering.
3) Terminate filtering at any time with button #1.

  USN Norfolk, VA  335
   8080    KHz
  10865
  16410
  20015

  USCG San Francisco, CA   4346
   8682    KHz
  12730
  17151
  22527

  CF Halifax, NS Canada  4271
   6330    KHz
  10536
  13510
 
 

512K Coco 3, 40 track DDDS drive 0, shortwave receiver with SSB/CW required.

1) Reception rates: 60, 90, 120 LPM
2) Pixels per line: 1536. That is equivalent to an IOC of 576. Image is monochrome.
3) Storage capacity: 1920 lines or 16 minutes at 120LPM
4) Memory capacity: one full image per 491K. 512K RAM required. Total image size 1536x1920 pixels.
5) DISK storage: 1 image per 40 track DDDS disk
6) Printer resolution (ex. Tandy DMP200) 1536 dots/line in three passes of 512 dots/line; tape strips side by side. Vertical capacity with fan fold paper: length of image.
 

For further reading on FAX transmissions, refer to the following articles and your local shortwave radio distributor.

"Weather...or  not",  by Marty Goodman, Rainbow, Feb. 1985. The author of the current program gratefully acknowledges the debt to Graphicom and their code. It helps to stand on the shoulders of giants.

"Build the RADFAX Decoder" by John Clarke, Popular Electronics, Nov.1990. An alternative approach and additional information.

"Guide to Facsimile Stations 10th ed."  by Klingenfuss available from most sources of shortwave radios; not Tandy. Details on FAX equipment, regulations, specification, frequencies and schedules.

Comments or help requests should be sent with a self addressed and stamped envelope to:

    Every effort has been made to see that this program is  trouble free, but it is impossible to plan for every eventuality. If you should encounter trouble, make sure  that  you are following the directions. Check the printer baud rate settings and drive side select code in CC3FAX. You can edit the values using CC3FAX. Remember to always make a backup and the put the original program disk away in a safe place. Do not use the original disk as a working disk!
    Try to keep the shortwave radio as far from the computer  system as possible. Don't expect reception conditions to be uniformly good. Reception of Naval FAX is beamed to the Atlantic and Pacific fleets and not to the Midwest (where we don't have navies.)
 

NFAX Norfolk    broadcasts their schedule at 00:00 GMT.
USGC San Francisco  "        "      "     "  20:19  "
CF   Halifax        "        "      "     "  10:14  "

For other problems, refer to the address previously given.