Aeronetworks sro - Airborne Linux

To backup or not to backup.  That is the question. Who likes to make backups? Anyone, Anyone? Hmm, I thought so... Versioned Backups I prefer to make backups with very simple tools, since when things go south, I don't want to have to install a complicated system just to get my data back. Most UNIX backup systems are based on rsync and by using a careful system of  hard links (multiple new names for the same old file), differential backups can save you oodles of disk space in the long run, while making it very easy to step through an archive and retrieve specific versions of old files: https://www.nongnu.org/rdiff-backup/ http://www.mikerubel.org/computers/rsync_snapshots/ https://popey.com/blog/2020/12/straightforward-linux-backups-with-rsnapshot/ Three for the Price of One The original article by Mike Rubel describes how to keep three backups for the price of one, using a combination of hard links and rsync . That idea then spawned the rsnapshot (pull) and r...

Who didn't play with whirlygigs as a child?  I sure had hours of fun with paper and wood twirly whirlies, but I frequently wondered about making something bigger, that can produce useful power. Fifty odd years later... Little Alternator with 6 LEDs A small three phase alternator that can be had for the princely sum of about $5 from aliexpress.com, can produce a few Watts of power.  Twirl it by hand to light up 6 LEDs. I took it to our production manager Siegfried Losch, who is always willing to play with a new toy and we stuck it into a drill press.  With no load, it generated 14V AC rms when running at 3000 rpm.  So it can charge a 12V SLA motor cycle battery when hooked to a high speed engine, but it will not do much with a wind rotor that will only turn at about 200 rpm or less. If you are content with 6 or maybe 12 LEDs to light up a little tree in your backyard, then you can skip all the electronics below, get some balsa and go carve a propellor. ...

A Circular Polarized Quad Patch Array for the 900 MHz ISM Band Driving a patch array antenna is a tricky and multidisciplinary affair - a combination of electrics, magnetics and mechanics - where theory meets reality.  Patch antennas are useful between about 1 and 5 GHz.  Below that, they are too big and above that, too small to be practical for the manufacturing tolerances of a hobbyist.  For L, S and C-band, a radio amateur can use patches with good effect, using not much more than tin snips and a nibble tool. 902-928 MHz ISM Band LCP Quad Patch Antenna The patch antenna theory can be explored with a simulation program such as NEC2: https://www.aeronetworks.ca/2018/07/patch-antenna-design-with-nec2.html You could make an array with any number of patches, but more than four would be a whole lot of hassle.  A SAR radar antenna may have 300 tiny little patches.  However, a two by two is about the limit of my patience. Any piece of metal within half ...

The most annoying thing on my Mac is ( was! ) the Adobe Flash Updater .  This annoying program will pop up and steal the focus and it doesn't actually work.  It never succeeds in updating the Adobe Flash plugins. The only way to do an update is to go to the Adobe web site with a web browser and download their apps again and install them manually. Man will only be free,  once the last computer has been strangled  with the power cable of the last router. — With apologies to Didero. There are many pages on the wild wild web that suggest how to suppress this atrocious thing, but I have not seen a method that actually works.  So I hunted all Adobe updaters down with the top , kill and  find commands and then rooted them out with brute force: $ sudo su - password # find / -name "Adobe*app" ...  # cd /Library/Application\ Support/Adobe/ARMDC/Application/ # mv "Adobe Acrobat Updater.app" "Adobe Acrobat Updater.bad" # cd /Applicatio...

GNU Radio on Linux Software Defined Radio requires a reasonably fast computer and won't work properly on a virtual machine.  The heart of Free SDR is of course GNU Radio, from here https://www.gnuradio.org/ and here https://wiki.gnuradio.org/index.php/Main_Page. I like the GQRX program which I use with the RTL-SDR and Great Scott Gadgets HackRF One and these are all very well supported on Linux and Mac as described here http://gqrx.dk/tag/hackrf.   While I can make this work on my Mac, whenever Apple releases a large OS update, I have to re-install the whole house of cards all over again.  This gets very tiring after a while. So to get this lot working and keep it working, I bought a nice new Intel NUC https://www.intel.com/content/www/us/en/products/boards-kits/nuc.html and installed Ubuntu Linux Server 18.04 LTS on it. This is a long term support (10 year) Linux version which means that it will get security updates, but the essentials will remain mor...

If you want to listen to Jupiter sing , bounce a message off the Moon , or bounce off aircraft , random space junk , or meteor trails , talk to a Satellite , or a little unmanned Aircraft , you need a very high gain antenna.  An easy way to make one, is from an old C-band satellite TV, Big Ugly Dish (BUD). Considering that the amount of space junk is ever growing, Junk Bounce Communications (TM) can only improve.  An advantage of Junk Bounce is that it works at any frequency, from UHF up to K-band, so orbiting space junk could become the new ionosphere, a neat radio wave reflector around the planet! To use an unknown dish, you need to find its focal point and then make a little antenna with a good front to back ratio, to use as a feed. Focal Length The focal point of a parabola is easy to find using some forgotten high school geometry: Measure the diameter (D) and the depth (d) of the dish. The focal length F = D^2 / 16 x d Note that an offset feed dish is o...