UAV Communications And Mission Systems

Tactical Unmanned Air Vehicles present an interesting communications challenge. Flying an RC toy in your back yard is fun, but controlling a heavy aircraft, hundreds of kilometers away over the desert, is something else entirely. Abu Dhabi IDEX 2021 walk through: https://youtu.be/PkNzGEeBOBo

ADASI 500 kg Unmanned Helicopter ready for IDEX 2021

The below book is still a draft and it is published here as a series of PNG files - one per page. The below should be viewable in any browser. If you wish to get a PDF file, send a message to herman at aeronetworks dot ca and then we can agree on which FTP service to use.

Enjoy!

Herman

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Unlock CRA PDF Forms

Unlock Canada Revenue Agency PDF Forms It appears that there is a relatively new PDF feature to prevent casual copying and saving of a file and that some programs save PDF files with these foolish features active by default. Many forms from the Canada Revenue Agency are locked in this way, which makes it difficult to do one's taxes, since one can fill the form, but cannot save it. One can only print the form. It should be possible to print to a file or export it to a new PDF file, but it is far better to reset the annoying anti-taxpayer flags, since the 'printed' form cannot be edited easily any more and I always manage to make a mistake or three that need to be corrected after review. If there is a Linux (virtual) machine handy, install qpdf and use it to reset the silly flags: $ su - password # dnf update # dnf install qpdf # exit $ qpdf --decrypt lockedfile.pdf unlockedfile.pdf One doesn't need a password to unlock these flags, so the fix is instant. La voila! He...

Parasitic Quadrifilar Helical Antenna

This article was reprinted in OSCAR News, March 2018: http://www.amsat-uk.org If you want to receive Satellite Weather Pictures , then you need a decent antenna, otherwise you will receive more noise than picture. For polar orbit satellites, one needs an antenna with a mushroom shaped radiation pattern . It needs to have strong gain towards the horizon where the satellites are distant, less gain upwards where they are close and as little as possible downwards, which would be wasted and a source of noise. Most satellites are spin stabilized and therefore the antenna also needs circular polarization, otherwise the received signal will flutter as the antennas rotate through nulls. The helical antenna, first proposed by Kraus in 1948, is the natural solution to circular polarized satellite communications. It is a simple twisted wire - there seems to be nothing to it. Various papers have been published on helix antennas, so the operation is pretty well ...

Weather Satellite Turnstile Antennas for the 2 meter Band

NEC2, 2 m band, 146 MHz, Yagi Turnstile Simulation and Build This article describes a Turnstile Antenna for the 2 meter band, 146 MHz amateur satcom, 137 MHz NOAA and Russian Meteor weather satellites. Weather satellite reception is described here . A quadrifilar helical antenna is described here . Engineering, is the art of making what you need, from what you can get. Radiation Pattern of the Three Element Yagi-Uda Antenna Once one combine and cross two Yagis, the pattern becomes distinctly twisted. The right hand polarization actually becomes visible in the radiation pattern plot, which I found really cool. Radiation Pattern of Six Element Turnstile Antenna Only a true RF Geek can appreciate the twisted invisible inner beauty of a herring bone antenna... Six Element Turnstile Antenna Essentially, it is three crosses on a stick. The driven elements are broken in the middle at the drive points. The other el...

Aeronetworks sro - Airborne Linux

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