Collaborate Disseminate
Antennas come in many shapes and sizes, with a variety of characteristics making them more or less suitable for various applications. The average hacker with only a middling exposure to RF may be familiar with trace antennas, yagis and dipoles, but there’s a whole load more out there. [Eric Sorensen] …read more
Watch Justin McAllister’s presentation on simple antennas suitable for a zombie apocalypse and two things will happen: you’ll be reminded that everything antennas do is amazing, and their reputation for being a black magic art will fade dramatically. Justin really knows his stuff; there is no dangle-a-wire-and-hope-for-the-best in his examples. …read more
Continue reading Justin McAllister’s Simple, Post-Apocalypse-Friendly Antennas
Ham radio isn’t just one hobby. It is a bunch of hobbies ranging from chatting to building things, bouncing signals off the moon, and lots of things in between. Some of these specialties, such as supporting disaster relief or putting odd locations “on the air”, require portable operation. To encourage disaster readiness, hams participate in Field Days which is a type of contest that encourages simulated emergency conditions. So how do you erect an antenna when you just have a few hours to set up a temporary station? [KB9VBR] shows how he and his friend used a Chameleon Emcomm III …read more
Not long ago, we published an article about researchers adding sensor data to passive RFID tags, and a comment from a reader turned our heads to a consumer/maker version which anyone can start using right away. If you’re catching up, passive RFID technology is behind the key fobs and stickers which don’t need power, just proximity to the reader’s antenna. This is a much “hackier” version that works with discrete signals instead of analog ones. It will not however require writing a new library and programming new tags from the ground up just for the user to get started, so …read more
If you watch old science fiction or military movies — or if you were alive back in the 1960s — you probably know the cliche for a radar antenna is a spinning dish. Although the very first radar antennas were made from wire, as radar sets moved higher in frequency, antennas got smaller and rotating them meant you could “look” in different directions. When most people got their TV with an antenna, rotating those were pretty common, too. But these days you don’t see many moving antennas. Why? Because antennas these days move electrically rather than physically using multiple antennas …read more
Continue reading No Moving Parts: Phased Array Antennas Move While Standing Still
5G is gearing up to be the most extensive implementation of mesh networking ever, and that could mean antennas will not need to broadcast for miles, just far enough to reach some devices. That unsightly cell infrastructure stuck on water towers and church steeples could soon be hidden under low-profile hunks of metal we are already used to seeing; manhole covers. This makes sense because 5G’s millimeter radio waves are more or less line-of-sight, and cell users probably wouldn’t want to lose connectivity every time they walk behind a building.
At the moment, Vodafone in the UK is testing similar …read more
Making wine isn’t just about following a recipe, it’s a chemical process that needs to be monitored and managed for best results. The larger the batch, the more painful it is to have something go wrong. This means that the stakes are high for small vineyards such as the family one [Mare] works with, which have insufficient resources to afford high-end equipment yet have the same needs as larger winemakers. The most useful thing to monitor is the temperature profile of the fermentation process, and [Mare] created an exceptional IoT system to do that using LoRa wireless and solar power. …read more
Continue reading Solar-Powered IoT Sensor Saves Wine Batch From Overheating
[Mare] has a visual guide and simple instructions for making DIY mini helical 868 MHz antennas for LoRa applications. 868 MHz is a license-free band in Europe, and this method yields a perfectly serviceable antenna that’s useful where space is constrained.
The process is simple and well-documented, but as usual with antenna design it requires attention to detail. Wire for the antenna is silver-plated copper, salvaged from the core of RG214U coaxial cable. After straightening, the wire is wound tightly around a 5 mm core. 7 turns are each carefully spaced 2 mm apart. After that, it’s just a matter …read more
Continue reading DIY Mini Helical Antennas From Salvaged Co-ax Cable
We’ve seen our share of 3D printed antennas before, but none as well documented and professionally tested as [Glenn]’s 3D printed and metalized horn antennas. It certainly helps that [Glenn] is the principal engineer at an antenna testing company, with access to an RF anechoic chamber and other test equipment.
Horn antennas are a fairly simple affair, structurally speaking, with a straight-sided horn-shaped “cone” and a receptacle for standardized waveguide or with an appropriate feed, coaxial adapters. They are moderately directional and can cover a wide range of frequencies. These horns are often used in radar guns and as feedhorns …read more
Continue reading Fully 3D Printed And Metalized Horn Antennas Are Shiny and Chrome
With the explosion in cell phones, WiFi, Bluetooth, and other radio technologies, the demand for antennas is increasing. Everything is getting smaller and even wearable, so traditional antennas are less practical than ever. You’ve probably seen PCB antennas on things like ESP8266s, but Drexel University researchers are now studying using titanium carbide — known as MXene — to build thin, light, and even transparent antennas that outperform copper antennas. Bucking the trend for 3D printing, these antennas are sprayed like ink or paint onto a surface.
A traditional antenna that uses metal carries most of the current at the skin …read more