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.

SSTV from VK3ASC/P on VK3/VE-129

Sunday afternoon 15 Jun 2014: Mark VK3ASC came up on 20m and I was able to work him on SSB over a distance of only 413km. After that he went to 40m and started sending on SSTV. Nothing was heard for a while and then Matt VK2DAG mentioned he was actually sending on USB. Normally SSTV is sent on the regular sideband used for voice. Anyway, after a re-send, I caught my first picture from Mark on Mt Lawson VK3/VE-129 using MMSSTV. After that he moved to 30m and sent it again, but I could no longer copy, even though 20m worked fine 40 mins earlier. The wonders of HF propagation!

Thanks for sending a picture from another summit, Mark!

Mt Lawson VK3/VE-129  via 40m SSTV

Mt Lawson VK3/VE-129 via 40m SSTV

SSTV from VK3ASC/P on VK3/VE-208

Mark, VK3ASC activated summit VK3/VE-208 Jarvis Creek Plateau on PSK31 and SSTV Saturday afternoon 31 May 2014. On 30m he sent a picture of the summit a number of times on Slow Scan TV. The first attempt was using Scottie 1 mode which takes nearly 2 minutes for a 240 line picture of 320 pixels. I was using MMSSTV but the software did not recognise the start of the picture so I kicked it off manually and so only received the bottom part of the picture.


Mark is using Wolphi’s DroidSSTV software on his Android smartphone. I suggested he switch to Scottie 2 which reduces the transmission time to just over a minute. At the same time, I was fiddling with the audio input level on my soundcard as the level was saturating. This could cause the failure to recognise the start of the picture due to audio distortion even though SSTV is really an FM mode so amplitude variations should play no part. This is what was received in Scottie 2 mode:


The start of the picture was being recognised and the whole frame was received. There was quite a lot of sparkly noise in the frame so Mark suggested sending again. I further reduced the input level in case the audio was still saturating. There were quite a few static crashes but it seemed as though the picture could be improved. The final picture received was this:


There was a lot less noise this time and it was much more recognisable. Mark attempted to raise the contrast in this picture by adjustments in the DroidSSTV app but it seemed to have no obvious effect. Certainly, a great first attempt at sending and receiving an SSTV image from a summit. Also check out Matt VK2DAG’s blog as he received the images too.

Thanks to Mark, VK3ASC!