ÖVSV, ATV, APRS, ARISS,… these are abbreviations most of us might not be familiar with. They come from amateur radio communication – something we want to introduce and maybe raise your interest in with this article!

Preparation of the antennas for Passepartout Sherpa take oft

But first, lets cover the basics. Radio waves are, like ligth and radar, electromagnetic waves. Other than ripples on water after we have dropped a stone in it, these waves are 3D and propagate through space. One could assume that these waves move matter when they go past it – but this is not the case. Only energy gets tansported. An example can be leaves which are floating on a pond: Even though waves make them move up and down, they still stay in the same space. Electromagnetic waves do not need a medium to propagate (for example, sound waves need air to travel along). An antenna (which can be as simple as a piece of wire) can be excited by the wave. It needs to be set into resonance with the incoming wave.
People who have amateur radio communication as their hobby, have many reasons for this. Two reasons might be the ability to get into contact with people from all over the world, or to beeing able to help in emergency situations. In order to build a network of Austrian Radio Operators, the ÖVSV (Österreichischer Versuchssenderverband, Austrian Trial Senders Community) was founded in 1925, which is still active today – even after being closed down between 1938 and 1954. Private contacts inititated the collaboration between the Austrian Space Forum and the ÖVSV short before the first take off of one of our balloons. Several members of the space forum are also amateur radio operators themselves. 6 videocameras, a 2m APRS sender and packet radio equipment were present at the first start of Passepartout. But what are those things, and what are they used for?
Packet Radio is a system for data exchange.With this system a file will be “chopped” into several small packages to be transferred. At the receiver’s end, the packages are then assembled again. Via controlls of the distinct packages, errors can be avoided. The system has been developed on Hawaii, to enable the communication between the University’s computers which were distributed over several islands. This lead to the development of the socalled digipeater which is an automated send/receive station, which enables messages to travel for up to 100km. Long before the development of the internet, radio operators enabled the exchange of news and information between computers. Up to today, this system can be used as an emergency system in case of internet breakdowns.

An emergency signal is send via a 2m band and enables us to locate the position of the balloon.

APRS (Automatic Packet Reporting System) is a mobile version of the Packet Radio and is used on mobile platforms like trucks – and also with Passepartout. Data (like GPS positions) are sent off automatically. To stop the system from being overloaded, it only gets send to the next APRS Digipeater. It uploads the data into the internet from where it is available for our team.
This method can be used as an emergency system: The signal is transponded both via Digipeaters and the internet. There are several other systems and gadgets available, but lets move on to some of the most exciting aspects of amateur radio operating: Can you provide your own weather forecast, or have a little chat with the crew onboard ISS? A few years ago, no one would have believed if you said you could do those things – but today, this isn’t even that unusual any more!

During the time it takes the ISS or a satellite to fly over an area, many things can be communicated: images, short chats – well, even small concerts can be sent to Astronauts. Geostationary satellites like weather satellites are a special case, since they stay over the same spot, allowing a multitude of data to be communicated. From time to time you might hear from amateur radio satellites: These satellites are about 10x10x10cm big and use batteries or solar panels. They are usually built by amateur radio clubs or students. Collaboration between different groups is a very important part – at one point, amateuer radio operators have even helped NASA to find a satellite again!

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