[aprssig] high altitude balloon / Raspberry Pi SSTV / RTTY tracking

Thomas Krahn thomas at tkrahn.com
Fri Jul 20 13:09:02 EDT 2012


Just a few clarifications. The hams in the UK are not allowed to use 
their amateur license on flying objects such as planes or balloons.
Therefore they need to use unlicensed transmitters with low power in the 
70 cm range. They won't use their callsign for that, though many of them 
have one.

Since APRS is for amateur radio only, they use some kind of RTTY with 
300 baud (FSK) and decode it with a ssb receiver and fldigi.
Their tracking site is http://spacenear.us/tracker/ which is some kind 
of equivalent to aprs.fi

The balloon with the Raspberry Pi was actually transmitting the webcam 
pictures with SSDV rather than sstv. It is a digital version of a packet 
based, live image transmission at low baud rates.
The geniality about SSDV is that multiple distributed receiving stations 
forward their received data to a server on the internet where the data 
is combined and the image is reconstructed for everyone visible in a web 
See http://ukhas.org.uk/guides:ssdv


On 07/19/2012 11:27 PM, Keith VE7GDH wrote:
> I searched back over the last few days and couldn't find a mention of
> this project on here, so here goes...
> http://www.bbc.co.uk/news/technology-18900862#
> http://www.raspberrypi.org/archives/1620
> http://www.uk.amsat.org/8978
> http://www.daveakerman.com/?p=592
> I believe the project was by Dave M5AKA but it took a bit
> of digging to find the callsign. The balloon made it to 39,994
> metres and the Raspberry Pi sent SSTV images tot he ground.
> They were tracking it, but it isn't entirely clear if APRS was
> used. SSTV was just 10 mW on 434.650 MHz. There was also
> a GoPro onboard. One of the pages actually mentioned RTTY
> for the telemetry, so perhaps APRS wasn't involved.
> 73 es cul - Keith VE7GDH
> -- 
> "I may be lost, but I know exactly where I am!"
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