SSTV from VK3ASC/P on VK3/VE-105

Sunday afternoon and another summit activation by Mark VK3ASC, this time on Mt Big Ben VK3/VE-105. He came up on 20m SSB and surprised me by being an easy 5×9 copy over the short 473 km path. Half an hour later after scooping up some of the regular SSB SOTA chasers on 40m he popped up on 7180 with a spot announcing SSB/SSTV. I found Mark chatting to Matt VK1MA who was setting up MMSSTV to receive a picture. Pretty soon after that the chirping sounds of SSTV were coming through. I was still getting MMSSTV running on the right sound port and so ended up missing the first 10 seconds of the picture. The software still managed to start itself automatically from the horizontal sync pulses so I did get a picture, albeit without the blue sky at the top. Here it is:

Mt Big Ben - first picture

Mt Big Ben – first picture

Yep, a pretty grainy picture which was no surprise considering Mark was about S2 and dropping into the noise. I did have trouble understanding all that he was saying, a far cry from the armchair contact half an hour before on 20m. There was also a lot of static crashes and it turned out there were 2 storm cells within radio range as you can see on the lightning map:

Active lightning storms within range on 40m

Active lightning storms within range on 40m

Mark sent the picture again and this time it did not start properly, then about 20% of the picture was received and then there was a resync and restart with another 20% being received. None of those were saved, but it was indicative of how poor the conditions were.

Mark sent the picture a third time, and signals seemed to improve. I managed to receive the whole frame this time, though there was still quite a bit of noise. The blue sky was obvious now…

Mt Big Ben - second picture

Mt Big Ben – second picture

A frame was also received by Matt VK1MA, and he reported significant slant to the image. So, not ideal conditions,  but an impression of the summit was received. There has been some discussion on the SOTA reflector about using digital transmission methods for SSTV images. With the very poor signals experienced I don’t think anything would have been received without use of very strong forward error correction – which is not currently available. There is certainly a place for analogue SSTV.

Mark later went up to 20m and announced another SSB/SSTV spot. It was less than an hour since I worked him on that band but by then his signal was nowhere to be seen. As it turned out, 30m would have been the optimal band for the path.

Thanks for another picture, Mark.

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