The tuning spectral display is the easiest and quickest way to adjust a SSB SSTV signal to the correct frequency. Slow Scan TV audio subcarrier signals have a distinct and easily recognized spectral shape. The sync signal will typically appear as a pulsing spectral peak at the 1200 Hz marker on the left. The 'video' portion of the signal spans the range of 1500 Hz to 2300 Hz, which falls between the two right markers. Under good s/n conditions the spectral display will display very little spectral energy outside the sync and video areas. Under noisy conditions, the display will not be as clean, but the basic SSTV 'signature' shape should still be visible.
Properly Tuned SSTV Signal: Notice the sync pulse on the left, and the video content between the video frequency edge markers.
SSTV Signal Too High in Frequency: The SSTV signature signal appears shifted to the right, with the sync peak well above the 1200 Hz marker. Lower the receiver frequency to shift the signal back into range.
SSTV Signal Too Low in Frequency: The SSTV signature signal appears shifted to the left, with the sync peak well below the 1200 Hz marker. Increase the receiver frequency to shift the signal back into range.