Dec 162017
 
A slow scan television program for HAM hackers.
File SSTV2.ZIP from The Programmer’s Corner in
Category Science and Education
A slow scan television program for HAM hackers.
File Name File Size Zip Size Zip Type
AUDIOBUF.DAT 32768 12091 deflated
EYE.PIC 16384 5167 deflated
JUDY.PIC 16384 5299 deflated
NIEL.PIC 16384 4487 deflated
OLDMAN.PIC 16384 5756 deflated
RDSSTV2.DOC 4388 2056 deflated
RDSSTV2.EXE 44032 4018 deflated
RIDER.PIC 16384 5172 deflated
UNNAMED.PIC 16384 4597 deflated

Download File SSTV2.ZIP Here

Contents of the RDSSTV2.DOC file


RDSSTV2.EXE

Niel Wiegand - WA5VLZ
Jan 10, 1987


HARDWARE REQUIREMENTS

- 48 KB user memory after DOS is loaded
- Color Graphics Card
- TV or RGB or composite video monitor (TV works best because individual
dots blend together better)
- Game Control Adapter and special cable
- One diskette drive
- Graphics printer


SETUP AND OPERATION

Use the "mode co80" DOS command to put your display adapter into the
graphics mode.

Connect audio tape recorder for recording SSTV video from SW receiver.

Transformer couple recorder audio/speaker output to game control adapter
pin 2 (a-#1 button) and pin 4 (ground). Use an audio output transformer
such as a Radio Shack 273-1380.
______________________________
RECORDER )||(GAME CONTROL ADAPTER PIN 2
SPEAKER 8 )||(_ 1000 (A-#1 BUTTON)
TERMINALS OHM )||( OHM
_______________)||(_______________ GAME CONTROL ADAPTER PIN 4
AUDIO OUTPUT (GROUND)
TRANSFORMER


Tune SSTV signals as normal SSB.

Use analyze audio input function to check SSTV signal quality and to
confirm that your receiver is properly set on frequency. Tune for periodic
spikes down to the sync line with the rest a trace between black and
white.

Record sstv signal video.

Playback SSTV video while using input and view function.

Use change horz sync function to help jagged right edge due to loss of
sync.

Use change brightness and contrast to suit personal preference.

Use print function to obtain hard copy.

NOTE: DO NOT USE ANALYZE OR INPUT FUNCTIONS UNLESS SSTV VIDEO IS PRESENT
AT THE GAME CONTROL ADAPTER.


FUNCTION DESCRIPTIONS

ANALYZE AUDIO INPUT: Audio input through the game control adapter is
plotted on the screen.The vertical scale is marked for approximate
periods of white, black, and sync. 600 cycles are plotted then the program
waits for the next command. A typical SSTV signal will show periodic
spikes down to the sync line with the rest a trace between black and
white.A gray scale would look like stair steps. Use this function as a
tuning aid for setting your receiver on frequency. USE OF THIS FUNCTION
WITHOUT AUDIO CONNECTED WILL HANG UP YOUR SYSTEM.

MENU DISPLAY: Display function menu.

INPUT AND VIEW SSTV FRAME: Audio input through the game control adapter is
used to generate a sstv frame in three steps. First, wait for vertical
sync pulse. Second, store audio cycle periods in audio buffer. Third,
process audio buffer to form sstv frame. USE OF THIS FUNCTION WITHOUT
AUDIO CONNECTED WILL HANG UP YOUR SYSTEM.

VIEW SSTV FRAME: Audio previously input and stored in the audio buffer is
processed to generate a sstv frame.

LOAD SSTV FRAME: Load raw binary display data from data files on diskette.
(FILESPEC = [d:]filename[.PIC])

SAVE SSTVFRAME: Save the displayed sstv frame as raw binary data in data
file on diskette. (FILESPEC = d:filename[.PIC])

CHANGE SSTV FRAME PARAMETERS: Contrast, brightness, and horizontal sync
freq of the picture may be adjusted. This works in conjunction with view
sstv frame and the audio buffer. It has no effect on pictures loaded using
the load sstv frame function.

HELP AND INFORMATION FRAMES: This information is available here.

PRINT SSTV FRAME: Output displayed frame to the printer. Requires
graphics printer and DOS that supports a graphics screen print.


HIDDEN FUNCTIONS:

SAVE AUDIO BUFFER (Press Y): Copies digitized SSTV data from a 32KB
buffer to file a:audiobuf.dat. This function was implemented to support
program development.

LOAD AUDIO BUFFER (Press X): Copies file a:audiobuf.dat into a 32KB
program data buffer. This simulates the INPUT SSTV function (I). After
loading this buffer VIEW and CHANGE will both work. This gives a good
feel for the program. This function was implemented to support program
development.


SSTV NOTES

Amateur SSTV is most likely to be heard near 28640, 7171, 14230, 21340 and
3845 KHz. 14230 is most popular. This program is designed to function
best with 60 Hz area standard B/W SSTV.

- sync freq 1200 Hz
- black 1500 Hz
- white 2300 Hz
- sweep rate 15 Hz

For more information on amateur SSTV see The ARRL Handbook for the Radio
Amateur (American Radio Relay League, Newington, Ct, 06111).




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