Why SSTV images become slanted
A small difference between the expected sound-card sampling clock and the actual clock appears in SSTV as a picture that gradually leans to one side. MMSSTV provides automatic, high-accuracy and manual methods for correcting this.
Automatic slant adjustment
Automatic slant adjustment periodically measures the interval between synchronization signals and corrects the picture while it is being received.
- Open Option → Setup MMSSTV.
- Select the RX tab.
- Enable Auto slant.
The same function can also be enabled from the RX window's right-click menu.
Manual slant adjustment
- Open the Sync tab.
- Press Slant.
- Click the upper-right edge of the white synchronization line.
- Click the lower-right edge of the same synchronization line.
MMSSTV recalculates the sound-card sampling clock and redraws the received image using the new value.
When the result is correct and should become the default setting, press Mem.
Fine phase adjustment
Poor conditions can occasionally cause the image to begin at the wrong horizontal position. This may also produce incorrect colour alignment.
- Open the Sync tab.
- Press Phase.
- Click the left edge of the synchronization line.
MMSSTV then treats the clicked position as the left edge of the image.
AVT90
AVT90 does not contain synchronization pulses within the image data. MMSSTV therefore handles phase adjustment differently for this mode.