Category Archives: radio hacks

Global Radio Direction Finding in Your Browser

Radio direction finding is one of those things that most Hackaday readers are likely to be familiar with at least on a conceptual level, but probably without much first-hand experience. After all it’s not everyday that you need to track down a rogue signal, let alone have access to the infrastructure necessary to triangulate its position. But thanks to the wonders of the Internet, at least the latter excuse is now a bit less valid.

The RTL-SDR Blog has run a very interesting article wherein they describe how the global network of Internet-connected KiwiSDR radios can be used for worldwide …read more

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Posted in internet hacks, KiwiSDR, radio direction finding, radio hacks, sdr, triangulation | Leave a comment

The History and Physics of Triode Vacuum Tubes

The triode vacuum tube might be nearly obsolete today, but it was a technology critical to making radio practical over 100 years ago. [Kathy] has put together a video that tells the story and explains the physics of the device.

The first radio receivers used a device called a Coherer as a detector, relying on two tiny filaments that would stick together when RF was applied, allowing current to pass through. It was a device that worked, but not reliably. It was in 1906 that Lee De Forest came up with a detector device for radios using a vacuum tube …read more

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Posted in history, patents, radio hacks, triode | Leave a comment

The History and Physics of Triode Vacuum Tubes

The triode vacuum tube might be nearly obsolete today, but it was a technology critical to making radio practical over 100 years ago. [Kathy] has put together a video that tells the story and explains the physics of the device.

The first radio receivers used a device called a Coherer as a detector, relying on two tiny filaments that would stick together when RF was applied, allowing current to pass through. It was a device that worked, but not reliably. It was in 1906 that Lee De Forest came up with a detector device for radios using a vacuum tube …read more

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Posted in history, patents, radio hacks, triode | Leave a comment

VCF East: SDR on the Altair 8800

You’d be forgiven if you thought software defined radio (SDR) was a relatively recent discovery. After all, few outside of the hardcore amateur radio circles were even familiar with the concept until it was discovered that cheap USB TV tuners could be used as fairly decent receivers from a few hundred MHz all the way up into the GHz range. The advent of the RTL-SDR project in 2012 brought the cost of entry level SDR hardware from hundreds of dollars to tens of dollars effectively overnight. Today there’s more hackers cruising the airwaves via software trickery than there’s ever been …read more

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Posted in radio, radio hacks, retrocomputing, VCF, VCF East, VCF East XIII | Leave a comment

Hacked RC Transmitters Control All The Things

If you have lots of RC creations about, each with their own receiver, you’ll know that the cost of a new one for each project can quickly mount up – despite RC receivers being pretty cheap these days. What if you could use a NRF24L01+ module costing less than $3?

That’s just what [Rudolph] has done for his Hackaday Prize entry, rudRemote. Though many people already spin their own RC link with the NRF24 modules, this sets itself apart by being a complete, well thought out solution, easily scalable to a large number of receivers.

The transmitter can be made …read more

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Posted in nRF24L01+, radio hacks, rc, rudremote, Teensy, The Hackaday Prize, transmitter | Leave a comment

Tiny Transmitter Brings Out the Spy Inside You

When it comes to surveillance, why let the government have all the fun? This tiny spy transmitter is just the thing you need to jumpstart your recreational espionage efforts.

We kid, of course — you’ll want to stay within the law of the land if you choose to build [TomTechTod]’s diminutive transmitter. Barely bigger than the 337 button cell that powers it, the scrap of PCB packs a fair number of surface mount components, most in 0201 packages. Even so, the transmitter is a simple design, with a two transistor audio stage amplifying the signal from the MEMS microphone and …read more

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Posted in MEMS microphones, oscillator, radio hacks, resonator, saw, spy, surface acoustic wave, transmitter | Leave a comment

Sign of the Smith Chart Times

The Smith chart is a staple for analyzing complex impedance. [W2AEW] notes that a lot of inexpensive test gear like the MFJ-259B gives you complex readings, but fails to provide the sign of the imaginary part of the complex number. That makes it difficult to plot the results on a Smith chart or carry out other analysis. As you might expect, though, he has a solution for you that you can see in the video, below.

A common method is to increase the frequency slightly. In a simple case, you’d expect the imaginary part — the reactance — to go …read more

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Posted in radio hacks, Reactance, smith chart, w2aew | Leave a comment

Ham Reviews MiniVNA

[KB9RLW] wanted to build a vector network analyzer (VNA), but then realized he could buy a ready-made one without nearly the cost it would have been only a few years ago. The network in this case, by the way, is an electrical network, not a computer network. You can use a VNA to characterize components, circuits, antennas, and even feed lines at different frequencies. The miniVNA Pro is economical and can exercise circuits from 1 MHz to 3 GHz. You can see the review in the video below.

There are a few ways to actually create a VNA, but in …read more

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Posted in minivna, minvna pro, radio hacks, tool hacks, vector network analyzer, vna | Leave a comment

Fail Of The Week: Never Assume All Crystals Are Born Equal

You should be used to our posting the hacks that didn’t quite go according to plan under our Fail Of The Week heading, things that should have worked, but due to unexpected factors, didn’t. They are the fault, if that’s not too strong a term, of the person making whatever the project is, and we feature them not in a spirit of mockery but one of commiseration and enlightenment.

This FOTW is a little different, because it reveals itself to have nothing to do with its originator. [Grogster] was using the widely-available HC-12 serial wireless modules, or clones or even …read more

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Posted in radio, radio hacks, radio module, serial wireless module | Leave a comment

Umbrella and Tin Cans Turned into WiFi Dish Antenna

There’s something iconic about dish antennas. Chances are it’s the antenna that non-antenna people think about when they picture an antenna. And for many applications, the directionality and gain of a dish can really help reach out and touch someone. So if you’re looking to tap into a distant WiFi network, this umbrella-turned-dish antenna might be just the thing to build.

Stretching the limits of WiFi connections seems to be a focus of [andrew mcneil]’s builds, at least to judge by his YouTube channel. This portable, foldable dish is intended to increase the performance of one of his cantennas, a …read more

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Posted in parabola, parabolic, radio hacks, reflector, waveguide, wifi, wireless hacks | Leave a comment