antenna

241 Articles

A Hacker’s Approach To All Things Antenna

March 16, 2025 by 13 Comments

When your homebrew Yagi antenna only sort-of works, or when your WiFi cantenna seems moody on rainy days, we can assure you: it is not only you. You can stop doubting yourself once and for all after you’ve watched the Tech 101: Antennas webinar by [Dr. Jonathan Chisum].

[Jonathan] breaks it all down in a way that makes you want to rip out your old antenna and start fresh. It goes further than textbook theory; it’s the kind of knowledge defense techs use for real electronic warfare. And since it’s out there in bite-sized chunks, we hackers can easily put it to good use.

The key takeaway is that antenna size matters. Basically, it’s all about wavelength, and [Jonathan] hammers home how tuning antenna dimensions to your target frequency makes or breaks your signal. Whether you’re into omnis (for example, for 360-degree drone control) or laser-focused directional antennas for secret backyard links, this is juicy stuff.

If you’re serious about getting into RF hacking, watch this webinar. Then dig up that Yagi build, and be sure to send us your best antenna hacks.

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DIY Yagi Antenna Sends LoRa Signals Farther

February 20, 2025 by 26 Comments

LoRa gear can be great for doing radio communications in a light-weight and low-power way. However, it can also work over great distances if you have the right hardware—and the right antennas in particular. [taste_the_code] has been experimenting in this regard, and whipped up a simple yagi antenna that can work at distances of up to 40 kilometers.

The basic mathematics behind the yagi antenna are well understood. To that end, [taste_the_code] used a simple online calculator to determine the correct dimensions to build a yagi out of 2 mm diameter wire that was tuned for the relevant frequency of 868 MHz. The build uses a 3D-printed boom a handle and holes for inserting each individual wire element in the right spot—with little measuring required once the wires are cut, since the print is dimensionally accurate. It was then just a matter of wiring it up to the right connector to suit the gear.

The antenna was tested with a Reyas RYLR998 module acting as a base station, with the DIY yagi hooked up to a RYLR993 module in the field. In testing, [taste_the_code] was able to communicate reliably from 40 kilometers away.

We’ve featured some other unique LoRa antenna builds before, too. Video after the break.

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What The Well-Dressed Radio Hacker Is Wearing This Season

February 13, 2025 by 7 Comments

We’ve seen a lot of interest in Meshtastic, the license-free mesh network for small amounts of data over the airwaves. [Ham Radio Rookie] was disappointed with his Meshtastic node’s small and inefficient antennas. So he decided to make what we suspect is the world’s first Meshtastic necktie.

We assume the power is low enough that having it across your thorax is probably not terrible. Probably. The tie is a product of a Cricut, Faraday cloth, and tiny hardware (the Xiao ESP32S3 and the WIO SX1262 board). The biggest problem was the RF connector, which needed something smaller than the normal BNC connector.

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Communicating With Satellites Like It’s 1957

February 3, 2025 by 14 Comments

When the first artificial satellite, Sputnik, was put into orbit around Earth, anyone in the path of the satellite could receive the beeps transmitted by the satellite provided they had some simple radio equipment. Of course, there was no two-way communication with this satellite, and it only lasted a few weeks before its batteries died. Here in the future, though, there are many more satellites in orbit and a few are specifically meant for ham radio operators. And, like the ’50s, it doesn’t take too much specialized equipment to communicate with them, although now that communication can be two-way.

The first step in this guide by [W2PAK] is to know where these satellites are in the sky. The simplest way to do that is to use a smartphone app called GoSatWatch and, when configured for a specific location, shows the satellites currently overhead. After that it’s time to break out the radio gear, which can be surprisingly inexpensive. A dual-band handheld is required since satellite uplink and downlink can be on different bands, and the antenna can be made from simple parts as well as [W2PAK] demonstrates in a separate video. Combined, this can easily be done for less than $100. [W2PAK] also goes over the proper format and etiquette for a satellite contact as well, so a new operator can pick it up quickly.

Using satellites as repeaters opens up a lot of capabilities when compared to terrestrial communications. Especially for operators with entry-level licenses who are restricted to mostly VHF and UHF, it adds a challenge as well as significantly increased range compared to ground-based repeaters and line-of-sight communications. There are plenty of activities around satellites that don’t require a license at all, too, like this project which downloads weather imagery from weather satellites.

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Making The Longest-Distance Radio Contact Possible

January 25, 2025 by 29 Comments

One of the more popular activities in the ham radio world is DXing, which is attempting to communicate with radio stations as far away as possible. There are some feats that will earn some major credibility in this arena, like two-way communication with Antarctica with only a few watts of power, long-path communication around the globe, or even bouncing a signal off the moon and back to a faraway point on Earth. But these modes all have one thing in common: they’re communicating with someone who’s also presumably on the same planet. Barring extraterrestrial contact, if you want to step up your DX game you’ll want to try to contact some of our deep-space probes (PDF).

[David Prutchi] aka [N2QG] has been doing this for a number of years now and has a wealth of knowledge and experience to share. He’s using both a 3.2 meter dish and a 1.2 meter dish for probing deep space, as well as some custom feed horns and other antennas to mount to them. Generally these signals are incredibly small since they travel a long way through deep space, so some amplification of the received signals is also needed. Not only that, but since planets and satellites are all moving with respect to each other, some sort of tracking system is needed to actively point the dish in the correct direction.

With all of that taken care of, it’s time to see what sort of signals are coming in. Compared to NASA’s 70-meter antennas used to communicate with deep space, some signals received on smaller dishes like these will only see the carrier wave. This was the case when an amateur radio group used an old radio telescope to detect one of the Voyager signals recently. But there are a few cases where [David] was able to actually receive data and demodulate it, so it’s not always carrier-only. If you’re sitting on an old satellite TV dish like these, we’d certainly recommend pointing it to the sky to see what’s out there. If not, you can always 3D print one.

Motorized Coil Tunes Your Ham Antenna On A Budget

January 19, 2025 by 14 Comments

When it comes to amateur radio, one size definitely does not fit all. That’s especially true with antennas, which need to be just the right size for the band you’re working, lest Very Bad Things happen to your expensive radio. That presents a problem for the ham who wants the option to work whichever band is active, and doubly so if portable operation is desired.

Of course, there are commercial solutions to this problem, but they tend to be expensive. Luckily [Øystein (LB8IJ)] seems to have found a way around that with this low-cost homebrew motorized antenna coil, which is compatible with the Yaesu Automatic Tuning Antenna System. ATAS is supported by several Yaesu transceivers, including the FT-891 which [Øystein] favors for field operations. ATAS sends signals up the feedline to a compatible antenna, which then moves a wiper along a coil to change the electrical length of the antenna, allowing it to resonate on the radio’s current frequency.

The video below details [Øystein]’s implementation of an ATAS-compatible tuning coil, mainly focusing on the mechanical and electrical aspects of the coil itself, which takes up most of the room inside a 50-mm diameter PVC tube. The bore of the air-core coil has a channel that guides a wiper, which moves along the length of the coil thanks to a motor-driven lead screw. [Øystein] put a lot of work into the wiper, to make it both mechanically and electrically robust. He also provides limit switches to make sure the mechanism isn’t over-driven.

There’s not much detail yet on how the control signals are detected, but a future video on that subject is promised. We’re looking forward to that, but in the meantime, the second video below shows [Øystein] using the tuner in the field, with great results.

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Handheld Satellite Dish Is 3D Printed

December 23, 2024 by 11 Comments

Ham radio enthusiasts, people looking to borrow their neighbors’ WiFi, and those interested in decoding signals from things like weather satellites will often grab an old satellite TV antenna and repurpose it. Customers have been leaving these services for years, so they’re pretty widely available. But for handheld operation, these metal dishes can get quite cumbersome. A 3D-printed satellite dish like this one is lightweight and small enough to be held, enabling some interesting satellite tracking activities with just a few other parts needed.

Although we see his projects often, [saveitforparts] did not design this antenna, instead downloading the design from [t0nito] on Thingiverse. [saveitforparts] does know his way around a satellite antenna, though, so he is exactly the kind of person who would put something like this through its paces and use it for his own needs. There were a few hiccups with the print, but with all the 3D printed parts completed, the metal mesh added to the dish, and a correctly polarized helical antenna formed into the print to receive the signals, it was ready to point at the sky.

The results for the day of testing were incredibly promising. Compared to a second satellite antenna with an automatic tracker, the handheld 3D-printed version captured nearly all of the information sent from the satellite in orbit. [saveitforparts] plans to build a tracker for this small dish to improve it even further. He’s been able to find some satellite trackers from junked hardware in some unusual places as well. Antennas seem to be a ripe area for 3D printing.

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