Ferdig bygget flåte. Foto: Paul Henrik Wanderås

APRS tracking a scout adventure

In the first week of June Fagerstrand Scouts went on this year’s adventure. During the week, we should build our own rafts and sail 100 km on the Swedish river Klarälven. All fleets were APRS tracked so that parents and others who would follow us could see our positions on the map.

The technical challenge

This was the challenge: Four rafts should be APRS tracked 100 km long Klarälven in Värmland, Sweden where APRS coverage were lacking in large parts of the route. Out tracks should easily been seen by parents and others interested in a simple manner. All equipment needed to be waterproof, it would after all be used on board the rafts.


Byonics MT-AIO

Each raft had to be equipped with trackers. We chose to use Byonics Micro Trak AIO which is a complete, portable and waterproof APRS tracker at 10 watts. It consists of a 2 meter-transmitter, a controller and a TinyTrak3 Byonics GPS2OEM GPS receiver. The tracker is designed for easy use and operate with 8 standard AA batteries. Although this tracker work for a long while on batteries, it was necessary for such a long trip to swap batteries. We had therefore stocked up with IKEA batteries.

The scout group has its own call, LA1FSG and trackers were set up with this callsign and SSID from 1 to 4. SSID 5 was set up as a backup tracker if we ever need an additional tracker or one of the other trackers should fail.

Since trackers have two profiles were all trackers set up with two SSID’er so that if a tracker should fail, we could use the spare tracker. Then it would only be to change the profile of the other trackers and so we would be up and running with the correct SSID without anyone noticing it.


Jäger EDV I-gate

There is no use of the transmitted APRS signals if they are not received by an I-gate, and in the area we were going to sail we could not expect that we would APRS coverage. We therefore had to bring with us an I-gate. The german company Jäger EDV has developed an I-gate which is very easy to use. After configuring the I-gate it only needs power, antenna and internet connection to work. The I-gate is supplied both with and without an embeeded transceiver. On this trip we used an I-gate with an embedded transceiver. This excluded the needs for a separate transmitter, thus reducing the power consumption. The I-gate operates on 2 volts.

The I-gate was purchased for use in NRRL Emergency Communication Services, and it is pre-packed in the suitcase along with Byonics-trakcerne ready for action.

Internet Connections

Ice R90

Since we chose to use our own I-gate we also need to bring with us a broadband connection. Since our journey went in Sweden it was also important to have a solution that would not cost to much. Ice.net has coverage throughout Scandinavia and can be used within the entire coverage area without extra charge.

On the equipment list an Ice R90 router was added. This is a wireless router with opportunities for both wireless and wired connections. The router has an adapter for use on 12 volts. R90 is the most powerful router from Ice.net providing best connectivity in difficult conditions. It can be supplemented with external antenna for better coverage conditions.

Waterproof case

Both the I-gate and Ice router needed to be packed so that they did not get wet and destroyed even though if a problems with the raft should arise and everything else got wet. The equipment was therefore packed into a suitcase from Clas Ohlson where it was drilled holes for mounting of connectors for power and antennas. The suitcase was hung from the ceiling to further secure it from the water. Antennas for I-gate and Ice-router was mounted on the rafts. The antennas were mounted so that they would withstand rough treatment. Despite the fact that we had several harsh encounters with the vegetation the antennas were not damaged.


All this equipment needs electricity. Although the trackers went on AA batteries we needed to power the I-gate and Ice-router. A 72 Amp and 50 Amp battery was therefore packed in a plastic box and loaded aboard the raft. This was enough power to charge the phones if it should become necessary.

Own webpage

Picture from the tracking page.
Picture from the tracking page.

To allow parents, siblings, grandparents, aunts and uncles would to follow the journey a website was set up (aprs.scouts.no). The page was created with Google Maps and tracking data were obtained using the API from APRS.fi.

The entire website was put together in a short time and there were not time for testing. To work tracking data had to be collected at regular intervals and stored in its own database.

In view of this uncertainty and the need to maintain control of the trackers a mobile alert system was built. If the I-gate had not been active in 30 minutes or a tracker had been quiet for 60 minutes it should send out SMS alerts. In this way we could easily follow up if a battery change on trackers were required frequently than calculated. The SMS was received on a Nokia 206. A classic phone with good battery life as opposed to smartphones does it not require charging every night.

Everything functioned technically as it should, except that Canal Digital had a broken line so that the server running the solution lost its internet connection.

Safety communication

Midland G7 PMR radio

With four rafts on the river we needed a safety communication system. Since the radios had to be operated by non-licensees we chose to use PMR radios. As all other equipment we depend on radios not be recharged along the way, but were could swap batteries. We selected MIdland G7. These radios comes with rechargeable batteries but can also use AA batteries.

Radiocommunications between the rafts should prove to be very convenient. Especially when all four rafts would find a place to moor for the night or we would deal communal lunch. It was also good to be able to notify the other rafts when we had touched arock or were when did our way through the trees. The radios was also used to warn the other rafts against rocks, forests and backwaters. For others who are planning a trip with several rafts we higly recommended radio communication.


The trip

With all the infrastructure in place, it was just to embark on this summer’s big adventure. 21 scouts and leaders built their own rafts and sailed the 100 km on Klarälven, from Branäsäng to Gunnerud.

Building the rafts. Photo: Paul Henrik Wanderås

Before we could embark we had to build the rafts. They were built in the water and as scouts we used neither nails or screws, just rope lashing.

The rafts are built in three layers and of two elements. The first layer is built with the thickest logs. It is important that the logs are tightened together since it is this layer forming the fleet’s “foundation.” The next two teams built with thinner logs. When the first element was built it was just to go ahead with number 2. When both elements are built they are connect together. Finally lashed gunwale and A-frames of the tent. When all the work is finished, simply hang up the rescue buoy and make ready for sailing.

Each raft is 3 x 3 meter. Two rafts are connected together giving a 3 x 6 meter long raft.

All four rafts were built during a day of hard work. Since everyone was tired after the building and no one had experience with sailing rafts we decided to stay in Branäsäng and cast off the next morning.

Raft “train”. Photo: Pål Stagnes

Already on Branäsäng we got acquainted with mosquitoes that would persecute us for the entire trip. Luckily we had been warned in advance that there were a lot of mosquitoes and mosquito hats had been purchased for all. It turned out that this was the best investment for the entire trip. In daytime on the river we relaxed away from the bloodsuckers, but at night and early morning they were there in hordes. Despite extensive use of repellents we could hear the beating of the wings from the mosquitos buzzing around us and considered us as a kind of standing buffet. But tough scouts are not stopped by mosquitoes.

Our journey down Klarälven was a real adventure with several groundings and crashes with trees that lay beyond the river. On several occasions we had to work hard to get us away from rocks that suddenly appeared and which had a magical attraction for our raft. The same power of attraction as it appears that some of the trees along the river also had, and on several occasions had to ax up to chop us loose. One intense contact was so powerful that I feared that the fleet would receive major damage. Here there was only one thing to do, get cut us loose as quickly as possible. The scouts were sent into the tent told tolie in the crash position. Head down and hands to cover their head.

There were many trips into the water. Here from the dismantling of the rafts. Photo: Thomas Solvik

A hard grounding and rough encounters with the vegetation caused so extensive damage that we had to “seek a port of refuge” in a backwater to repair the damage. It was just to jump into the water and start the repairs. After several hours of work the raft were once again seaworthy and we could sail on.

We lost some time along the way and to bring us back into schedule  we had two nights on the river sailing. This got us away from the the worst hoards of mosquitoes too. To sail down the river at night was an awsome experience that most people only dream about.


Watch the movie from the adventure: