Sota sstv?

In reply to MM0FMF:

“So use the computer to compress the image, add a whole host of FEC and send a
decent quality image.”

You can take a look at HAMDRM on http://users.telenet.be/on4qz/

Peter - ON4UP

In reply to ON4UP:

Now you’re talking Peter.

Andy
MM0FMF

In reply to G6TUH:
Great to see this topic about SSTV on SOTA.

As mentioned in previous posts, its the thrill of sharing an image of the summit with others over HF radio or VHF/ UHF radio for that matter.

I use a FT-817ND with the Wolphi audio interface to work with the Droidsstv app on my Nexus 5 mobile phone. And its a really simple app to use. I also use PSK on the same interface with Droidpsk.

There is a small group of here in VK that are trying to get the ball rolling on other modes for SOTA Activations.
Gerard VK2IO, Matt VK2DAG, Matt VK1MA and myself are quite active experimenting with these modes on portable devices and the interest is growing.

SSTV I feel is a winner to use as part of your SOTA activations, to share some of your experience on the Hill with others.

Cheers
Mark - VK3ASC

Hi,

Of course Andy has a very good point, but something that has not been mentioned is the apparent fragility of digital SSTV. It took me a few minutes to start receiving analogue SSTV on HF (20m) on my netbook when I decided to have a look. Although no doubt the digital modes offer a perfect picture if the signal is good, I have yet to successfully decode any at all. After a few hours of faffing, I went back to analogue. It is remarkable how well it works down to very low signal levels and copes with fading and QRM. Also like with CW, the brain fills in a lot of the missing information when there are noisy areas on the picture.

In other words, it seems to be much easier and quicker to get useable results with analogue. No doubt when it works, digital will give better pictures. I appreciate though that this is probably largely a software/protocol/modem problem that could be addressed with better design.

Sometimes lack of complexity, ease of use and resilience is what is important to people.

The same seems to me to apply to AM versus DRM for short wave broadcasting.

73,

Ian.

So, looking at ‘easypal’ (don’t know if it’s the same with qsstv, haven’t looked yet…) there appear to be 2 ways of ‘transmitting a picture’:

One where you send the whole picture
and one where you send a link to where the receiving end can download the picture from.

I guess that sending the whole picture would be the only suitable way for a SOTA QSO? Otherwise, if there’s no mobile data available on the summit, there’s no way that the person there would be able to download any received pic…

Or have I missed my guess.

Anyway, having failed miserably to get anything displayed via easypal, I guess ‘normal’ SSTV would be the way to go :wink: I can do that via mobile phone/tablet, without lugging a netbook around, so probably the easiest thing to do!

Don

M0HCU

In reply to GW8OGI:
Hi Ian,

I found Easypal faster and easier to set up than Digipan. Yes you need a proper interface as for any sound card mode and yes selective fading can produce errors but there is error correction plus a nice feature where you can get your station to ask for a retransmission of the bits you missed. If you can get analogue TV to work through your interface then Digipal should be plug and play. Sometimes its the intimidation of new stuff that we find daunting and consequently don’t get it right first up.

If I can get it to run then anyone can. It helps if someone is sending you a series of pictures so you get some practice.

I have no analogue TV software - its Easypal or nothing. You suggest analogue TV would be better for weak noisy signals and you may be right but if you are getting 80% of the sync pulses then Easypal will work OK without repeats required.

Its fairly tolerant - I have copied Easypal from my R1000 rx speaker using air coupling over a metre to the notebook microphone and no wires so mobile phone acoustic coupling might work - if the program can be adapted.

Whatever you use, have fun.

73
Ron