Aeronetworks sro - Airborne Linux

    RC Foamie Vulcan Bomber It is reasonably easy and low cost to make a RC plane from Styrofoam.  Foam costs almost nothing - about Euro 2.50 for a block of 5x50x150 cm - and it is available in various thicknesses, 5, 8, 10 and 20 cm being common.   I am building a delta wing plane that resembles a Vulcan bomber, with a 1.2 m wingspan, and a Ducted Fan Engine inside the fuselage.   There are two kinds of styrofoam, Expanded Polystyrene (the stuff used for exterior insulation of a home) and Extruded Polystyrene (More smooth and easier to sand, but heavier and used for roof insulation). Both kinds will cut super smooth with a hot wire and it is the same plastic, so you can just as well use the cheaper and lighter white beady stuff, since if you tune your cutter temperature properly, then you don't need to use sand paper.   For reference, Polystyrene melts somewhere between 170 and 280 Celsius - it depends on the foam and the air pressure where you li...

We live in a village outside Bratislava in Central Europe.  This is prime agricultural land and there are infinite numbers of moles in the fields around us, so some will eventually stray into the garden.  Once they are enjoying the good life in the village, it can be hard to convince them to relocate. I tried a few things and can now present here the 100 Horse Power Mole Eliminator : It costs nothing and it works. If you have an old lawn mower, garden tractor, or moped, that may be easier to move around and it produces more global warming badness, but a car starts with the press of a button and a couple of hose pipes clicked together, to go from the driveway to the far end of the yard, works well enough.   The trick is to get all water out of the pipes before you start - lift it shoulder height and walk along the pipe a couple times. The exhaust of a modern car is not very hot and will not melt plastic, but I used a short piece of metal pipe since I really don't want...

The 1700 to 2400 MHz band (M1 to M6) is a good band for the secondary control channel of air and ground robotic vehicles.  Little radios made by Doodle Labs in Singapore are popular and this is an antenna solution specifically aimed at the Meshrider radios ( https://doodlelabs.com/products/mesh-rider-radios/nano/ ).  These antennas will certainly also work well with Microhard in Calgary Canada Nano 2.4 GHz ( https://www.microhardcorp.com/n2420.php ) radios. I employed Ye Olde Fashioned technique of carving an antenna out of double sided board with a ruler and a scalpel, using copper tape for little optimization experiments and fixing the mistakes.  Once one has the hang of it, it is possible to carve an antenna by hand in a day, vs waiting two weeks for a PCB factory.   Etching it is good, if you have the chemicals and safety paraphernalia on hand and know what you are doing. With these 6 to 8 dBi antennas, you do not need a precision tracking system.  ...

I wanted to do some advanced RF antenna development work and needed an electromagnetic field solver that is a bit more up to date than NEC2 .  Commercial solvers from Matlab , Ansys and others are hideously expensive (in the order of $20,000 to $50,000) and do not fit in the wallet of a hobbyist or a small consulting company.  Recently, openEMS became available and it fills the niche with a capable free tool.  In general, openEMS is a solver - a Finite-Difference Time-Domain (FDTD) numerical engine.  You interact with it through Octave , which is almost identical to Matlab .  You can watch a good video by Thorsten Liebig here: https://www.youtube.com/watch?app=desktop&v=ThMLf0d5gaE   Getting it to work is a little painful, but it is free, so bear with it - then save a backup clone, or a zipped copy of the whole virtual machine directory and NEVER update it, to ensure that it keeps going and doesn't get broken by future updates, right when you are ...