Tag Archives: Antenna

Measuring HF Signal Speeds In A DIY Coaxial Collinear Antenna

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Air Traffic Controllers use Automatic Dependent Surveillance-Broadcast (ADS-B) as an alternative to secondary radar to track aircraft. The ADS-B is transmitted by the aircraft and contains information such as GPS position, pressure, altitude, and callsign among other things at a 1090 MHz frequency, which can be decoded using any of a number of software tools.

[Mike Field] lives near an airport, and decided he wanted to peek into the tracking signals for fun. He turned to an RTL-based TV Dongle. Since the stock antenna was not cutting it, he decided to make one specifically for the 1090 MHz signal. His …read more

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Start Tracking Satellites with This Low-Cost Azimuth-Elevation Positioner

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Tracking satellites and the ISS is pretty easy. All you really need is an SDR dongle or a handheld transceiver, a simple homebrew antenna, and a clear view of the sky. Point the antenna at the passing satellite and you’re ready to listen, or if you’re a licensed amateur, talk. But the tedious bit is the pointing. Standing in a field or on top of a tall building waving an antenna around gets tiring, and unless you’re looking for a good arm workout, limits the size of your antenna. Which is where this two-axis antenna positioner could come in handy. …read more

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Start Tracking Satellites with This Low-Cost Azimuth-Elevation Positioner

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Tracking satellites and the ISS is pretty easy. All you really need is an SDR dongle or a handheld transceiver, a simple homebrew antenna, and a clear view of the sky. Point the antenna at the passing satellite and you’re ready to listen, or if you’re a licensed amateur, talk. But the tedious bit is the pointing. Standing in a field or on top of a tall building waving an antenna around gets tiring, and unless you’re looking for a good arm workout, limits the size of your antenna. Which is where this two-axis antenna positioner could come in handy. …read more

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3D Printed WiFi Reflectors Custom Designed for the Building

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Are you a wizard at antenna design? Chances are you’ve never even given it a try, but this tool could change that. Most home-made WiFi signal boosting antenna plans around the Internet share one feature: they are directional antennas or reflectors. But WiPrint is a tool for designing custom WiFi reflectors that map to the specific application.

If we want to increase the signal strength in two or three different locations the traditional solution is an omnidirectional antenna. The problem is, although a good omnidirectional antenna increases the signal power in those locations we want, it also increases the signal …read more

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3D Printed WiFi Reflectors Custom Designed for the Building

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Are you a wizard at antenna design? Chances are you’ve never even given it a try, but this tool could change that. Most home-made WiFi signal boosting antenna plans around the Internet share one feature: they are directional antennas or reflectors. But WiPrint is a tool for designing custom WiFi reflectors that map to the specific application.

If we want to increase the signal strength in two or three different locations the traditional solution is an omnidirectional antenna. The problem is, although a good omnidirectional antenna increases the signal power in those locations we want, it also increases the signal …read more

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[Jeri] Builds a Magnetic Loop Antenna

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Most new hams quickly learn that the high-frequency bands are where the action is, and getting on the air somewhere between 40- and 160-meters is the way to make those coveted globe-hopping contacts. Trouble is, the easiest antennas to build — horizontal center-fed dipoles — start to claim a lot of real estate at these wavelengths.

So hacker of note and dedicated amateur radio operator [Jeri Ellsworth (AI6TK)] has started a video series devoted to building a magnetic loop antenna for the 160- and 80-meter bands. The first video, included after the break, is an overview of the rationale behind …read more

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Snazzy Balun Lets Ham Use Off-The-Shelf Coax

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It’s a dilemma many hams face: it’s easy to find yourself with a big spool of RG-11 coax cable, usually after a big cable TV wiring project. It can be tempting to use it in antenna projects, but the characteristic impedance of RG-11 is 75 Ω, whereas the ham world is geared to 50 Ω. Not willing to waste a bounty of free coax, one ham built a custom 1:1 current balun for a 75 Ω dipole.

Converting between balanced and unbalanced signals is the job of a balun, and it’s where the device derives its name. For hams, baluns …read more

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FM Snake Feeds Off Radio Waves

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[Eric Brasseur] built a radio-detecting snake that consists of a LED that lights up when around reasonably strong radio waves. Near an FM radio mast you’ll find a huge amount of waste energy being dumped out in the 88 to 108 MHz range.

[Eric]’s rig consists of a pair of 1N6263 Schottky diodes, flip-flopped with one set of ends soldered to the antenna and the other ends soldered to the leads of the LED with about a foot of wire in between. The antenna can be a single wire as the diodes are soldered together. This one is around 4 …read more

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Piezomagnetic Trick Shrinks 2.5 GHz Antennas

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To a ham radio operator used to “short”-wave antennas with lengths listed in tens of meters, the tiny antennas used in the gigahertz bands barely even register. But if your goal is making radio electronics that’s small enough to swallow, an antenna of a few centimeters is too big. Physics determines plausible antenna sizes, and there’s no way around that, but a large group of researchers and engineers have found a way of side-stepping the problem: resonating a nano-antenna acoustically instead of electromagnetically.

Normal antennas are tuned to some extent to the frequency that you want to pick up. Since …read more

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Antenna Basics by Whiteboard

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Like a lot of people, [Bruce] likes radio controlled (RC) vehicles. In fact, many people get started in electronics motivated by their interest in RC. Maybe that’s why [Bruce] did a video about antenna basics where he spends a little more than a half hour discussing antennas. You can see the video below.

[Bruce] avoids any complex math and focuses more on intuition about antennas, which we like. Why does it matter that antennas are cut to a certain length? [Bruce] explains it using a swing and a grandfather clock as an analogy. Why do some antennas have gain? Why …read more

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