> The only other known use for voice-bandwidth data modes is for image > transfers, > which can send an SSTV-size picture, with a very > low error rate, in 30 seconds, using a bandwidth of 2400 Hz. > the same image, at the > same low error rate, can be sent in less than 2 minutes, using a > bandwidth under 500 Hz.
SSTV has traditionally uesed 2.4khz BW since the analog days. There will be quite some resistance from sstv operators to change this to 500hz and extend the waiting time from 1 min average to more than five min. (30 sec to 2 min numbers are incorrect) Everyone actually operating sstv will confirm ! Digital SSTV concentrates on one frequency per band. That is 2.4khz per band. There are no full automatic stations for digi-sstv, there is NO software to allow full auto operation. THERE ARE NO DIGI-SSTV ROBOTS ! Usually the digi-sstv arq operations are operator-initiated and NOT automatic. You can't compare that to pactor, you are behaving incorrectly to the bunch of digi-sstv operators. > In other words, just by accepting to wait longer for an image to > arrive, as is the current practice in SSTV, it is not necessary to use > a voice-bandwidth transmission mode. WRONG. 5 min for a single picture will kill the mode. > Recommendation: Voice-bandwidth data modes SHOULD NOT be introduced on > the HF bands. Automatic (Robot operated) Voice-bandwidth data modes SHOULD NOT be introduced on the HF bands. 73, Cesco, HB9TLK
