A frequent complaint you will hear about amateur radio is that it is a chequebook pursuit. Of course you can work the incredible DX if you spend $20k on a high-end radio, big antenna, and associated components. The reality is though that because it’s such a multi-faceted world there are many ways into it of which the operator with the shiny rig is taking only one.
On the commonly used HF and VHF bands at the lower end of the radio spectrum you will definitely find chequebook amateurs of the type described in the previous paragraph. But as you ascend into the microwave bands there are no shiny new radios on the market, so even the well-heeled licensee must plow their own furrow and build their own station.
You might think that this would remain a chequebook operation of a different type, as exotic microwave devices are not always cheap. But in fact these bands have a long history of extremely inexpensive construction, in which skilled design and construction as well as clever re-use of components from satellite TV systems and Doppler radar modules play a part. And it is a project following this path that is our subject today, for [Peter Knol, PA1SDB] has repurposed a modern Doppler radar module as a transmitter for the 10GHz or 3cm amateur band (Google Translate version of Dutch original). The best bit about [Peter]’s project is the price: these modules can be had for only three Euros.
Years ago a Doppler module would have used a Gunn diode in a waveguide cavity and small horn, usually with an adjacent mixer diode for receiving. Its modern equivalent uses a transistor oscillator on a PCB, with a dielectric resonator and a set of patch antennas. There is also a simple receiver on board, but since [Peter] is using a converted ten-Euro satellite LNB for that task, it is redundant.
He takes us through the process of adjusting the module’s frequency before showing us how to mount it at the prime focus of a parabolic antenna. FM modulation comes via a very old-fashioned transformer in the power feed. He then looks at fitting an SMA connector and using it for more advanced antenna set-ups, before experimenting with the attenuating properties of different substances. All in all this is a fascinating read if you are interested in simple microwave construction.
The result is not the most accomplished 10 GHz station in the world, but it performs adequately for its extremely low price given that he’s logged a 32 km contact with it.
Though we cover our fair share of amateur radio stories here at Hackaday it’s fair to say we haven’t seen many in the microwave bands. If however you think we’ve been remiss in this area, may we point you to our recent coverage of a microwave radio receiver made from diamond?
A while ago, [drygol] was asked to repair a few old Amiga keyboards. The key switches worked fine, but in the past decade or two, the flexible PCB ribbon connector has been mistreated, and was in an unworkable, nonfunctional state. The fragile traces underneath the green epoxy coating were giving way, but [drygol] found a few cool ways to repair these flex cables.
The end of this keyboard cable was beyond repair, but the Commodore engineers were gracious enough to leave a bit of slack in this keyboard connector. After cutting off the most damaged section, [drygol] had a strip of plastic, a few copper traces, and a green coating that had to be removed. The first attempt to remove this green covering used methanol, but that didn’t work. The next chemical attempt was with an epoxy solvent that contained nasty chemicals. This was applied to the end of the flex cable, with the remainder of the cable masked off by Kapton. It worked remarkably well.
In removing the Kapton masking tape, [drygol] discovered this green film sticks better to Kapton than it does to copper and plastic. A mechanical solution was found, allowing these keyboard cables to be easily repaired.
Of course, this was only half of the problems with these flexible circuits. Over the years, a few cracks appeared in the traces. To repair these broken traces, [drygol] turned to silver glue and a few laminations of Kapton to make this keyboard cable whole again. It worked, and the ancient keyboard was returned to service. Great work, and a fantastic observation for anyone with one of these keyboards sitting around: just grab a roll of Kapton to repair these circuits. It can’t get any easier than that.
The idea to use a Ikea table as a base for a 3D printer first came to [Wayne] as he used this table to support other 3D printer he had working in his business. He realized that, even after five years of use, the table showed no signs of wear or distortion. So he decided to start to work on a 3D printer based on this precise table, the one that used to hold the printer.
[Wayne] stacked two together and named it Printtable (pun intended?). This open source, cartesian rep-rap 3D printer looks pretty slick. With a build area of 340mm X 320mm and 300mm on the Z axis and a price tag for the parts starting as low as $395, seems like a pretty decent 3D printer. With some work sourcing the parts, maybe it can be even lower.
Or we can just wait until Ikea starts selling them.
The Raspberry Pi Foundation has put a lot of work into their software stack. You need only look at a few of the Allwinnner-based Pi clones for the best evidence of this, but the Pi Foundation’s dedication to a clean and smooth software setup can also be found in Noobs, their support for the Pi Hardware, and to a more limited extent, their open source GPU driver offerings.
Now PIXEL is available as a live CD for anything that has i386 written somewhere under the hood. The PC/Mac distribution is the same as the Pi version; Minecraft and Wolfram Mathematica aren’t included due to licensing constraints. Other than that, this is the full Pi experience running on x86 hardware.
One feature that hasn’t been overlooked by a singular decade-old laptop in the Pi Foundation is Pixel’s ability to run on really old hardware. This is, after all, a lightweight distribution for the Raspberry Pi, so you shouldn’t be surprised to see this run on a Pentium II machine. This is great for a school in need of upgrading a lab, but the most interesting thing is that we now have a new standard in Linux live CDs and Flash drives.
Tod Kurt knows a thing or two about IoT devices. As the creator of blink(1), he’s shipped over 30,000 units that are now out in the wild and in use for custom signaling on everything from compile status to those emotionally important social media indicators. His talk at the 2016 Hackaday SuperConference covers the last mile that bridges your Internet of Things devices with its intended use. This is where IoT actually happens, and of course where it usually goes astray.
Chances are good that you’ve already lost some blood to thermoforming, the plastics manufacturing process that turns a flat sheet of material into an unopenable clamshell package, tray inside a box, plastic cup, or leftover food container. Besides being a source of unboxing danger, it’s actually a useful technique to have in your fabrication toolchest. In this issue of Tools of the Trade, we look at how thermoforming is used in products, and how you can hack it yourself.
The process is simple; take a sheet of plastic material, usually really thin stuff, but it can get as thick as 1/8″, heat it up so that it is soft and pliable, put it over a mold, convince it to take all the contours of the mold, let it cool, remove it from the mold, and then cut it out of the sheet. Needless to say, there will be details.
The legitimate version of the Android app helped its operator use the 1960’s-era former Soviet howitzer. The trojanized version of this application did just the same, except it also phoned home to Russian military intelligence with its location. In addition to giving the Russian army valuable information about troop movements in general, it also led to the destruction of 80% of the cannons in question over two years.
The cited article goes into depth about how certain it is that a hacking group, referred to as FANCY BEAR, are nearly certainly responsible for the attack. The exploit has fingerprints that are not widely known outside of the security research community, and the use of the exploit against the Ukrainian army pretty much ties FANCY BEAR to the Russian military.
This is also the same exploit that was used against the Democratic National Committee in the United States. Attribution is one of the hardest parts of white-hat hacking — attackers don’t want to be found and will leave misleading clues when they can — but the use of the same proprietary malware in these two attacks is pretty convincing evidence that Russian military intelligence has also hacked into US political parties and NGOs.