After the success of the first UKHASnet Hack Weekend it was all agreed to rendezvous again but this time stay in a single place to work on UKHASnet projects. We were able to hire a house on the Isle of Wight where 10 people assembled on the friday after successfully negotiating the ferry and then actually finding the hidden house itself.
Work began immediately on various UKHASnet projects, this included firing up the my 3d printer to make cases for UKHASnet nodes and a moxon antenna, multiple nodes were built, coded and debugged and it was a great chance to push the network as we ended up having multiple gateways. The original idea was to recreate the flotilla however due to poor documentation of the Xadow GSM module which I had hoped to turn into a floating GSM gateway it took too long to actually get it all working and wasn’t going to be ready for the Sunday morning activity day. Instead we decided to try and do some range testing of the RFM69 modules.
Previously (excluding using balloons) the longest ranges achieved using UKHASnet was about 1.5km but it was generally felt that it should be possible to push this to line of sight. We therefore decided to split into three teams and see if we could push how far UKHASnet could work. Before we left we setup 2 nodes with serial consoles to allow us to a custom data i.e chat text (designated with ‘:’).
One team graciously volunteered to remain at the house and set up a repeater node on a fibreglass pole in the garden (RUSS1). The rest of us divided into two, one team going up to Tennyson Memorial on Tennyson Downs, there they setup AJ2 (a LPC812 with GPS which had originally been planned to put in the sea) as well as having PF01 as their chat console. The other team jumped in my car and we initially drove to Compton Bay car park. We were using AJ1 a 3d printed moxon antenna with an LPC812 on a MK2 board with an RFM69HW set to 100mW. AJ3 was our chat console based on an EMF Camp TIlda badge acting as an Arduino Due with a RFM69HW wired to its SPI. Coordination was via VHF radio and once we had established that both teams were in position we fired up the network, after a little bit of hacking of the chat console we were able to send packets from Compton Bay up to Tennyson Memorial and back again with a range of 5.4km.
We then decided to see if we could push the range further and headed down the coast setting up above Blackgang Chine on the cliff top. We could just see in the distance the Tennyson Downs and were able to get up a reliable link between the two which was a range of 18.57km. Packets sent from Blackgang were then repeated by the Tennyson node across to the house a further 3.34km giving a total of 21.91km.
It was great to be able to get out and actually test the nodes and push the ranges to beyond anything we’d tried before. 18.75km was beyond what we expected to achieve but it showed that the range is really based on line of sight and if you can get a well placed node you could cover a significant distance. All the nodes performed well, even with a simple 1/4 wave wire antenna it was possible to cover a good distance and it was relatively easy to put together the moxon antenna adding a bit of directionality and gain. It also was really good fun being able to chat across the mesh network and has inspired us to work on some new cool projects using the technology. Hopefully we’ll be able to get some more nodes installed in significant places and start to really expand the network.