Category Archives: radio

Radio Tuning The Quicksilver Way

Modern radios are often digital affairs, in which the frequency is derived from a stable crystal oscillator and varied through a microprocessor controlled frequency synthesiser. It won’t drift, and it’s exactly on the frequency dialed in. Older radios though relied on a tuned circuit, a combination of capacitor and inductor, for their frequency selection. If you were curious enough to peer inside — and we know you were — you’d have seen the moving vanes of a variable capacitor controlled by the tuning knob.

Of course, there is another way to adjust a tuned circuit: by changing the value of …read more

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Posted in coil, inductor, parts, permeability, radio, radio hacks, tuned circuit | Leave a comment

An Unconference Badge That’s Never Gonna Give You Up

When your publication is about to hold a major event on your side of the world, and there will be a bring-a-hack, you abruptly realise that you have to do just that. Bring a hack. With the Hackaday London Unconference in the works this was the problem I faced, and I’d run out of time to put together an amazing PCB with beautiful artwork and software-driven functionality to amuse and delight other attendees. It was time to come up with something that would gain me a few Brownie points while remaining within the time I had at my disposal alongside …read more

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Posted in badge, fractal antenna, london unconference, radio, radio badge, radio hacks, Raspberry Pi Zero | Leave a comment

Piezomagnetic Trick Shrinks 2.5 GHz Antennas

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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Posted in antenna, MEMS, physics, piezoelectric, radio, wireless, wireless hacks | Leave a comment

Doppler Module Teardown Reveals the Weird World of Microwave Electronics

Oscillators with components that aren’t electrically connected to anything? PCB traces that function as passive components based solely on their shape? Slots and holes in the board with specific functions? Welcome to the weird and wonderful world of microwave electronics, brought to you through this teardown and analysis of a Doppler microwave transceiver module.

We’ve always been fascinated by the way conventional electronic rules break down as frequency increases. The Doppler module that [Kerry Wong] chose to pop open, a Microsemi X-band transceiver that goes for about $10 on eBay right now, has vanishingly few components inside. One transistor for …read more

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Posted in antenna, Doppler, local oscillator, microwave, mixer, radar, radio, radio hacks, resonator, RF, teardown | Leave a comment

Attack Some Wireless Devices With A Raspberry Pi And An RTL-SDR

If you own one of the ubiquitous RTL-SDR software defined radio receivers derived from a USB digital TV receiver, one of the first things you may have done with it was to snoop on wide frequency bands using the waterfall view present in most SDR software. Since the VHF and UHF bands the RTL covers are sometimes a little devoid of signals, chances are you homed in upon one of the ISM bands as used by plenty of inexpensive wireless devices for all sorts of mundane control tasks. Unless you reside in the depths of the wilderness, ISM band sniffing …read more

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Posted in 433 mhz, ISM band, radio, radio control, radio hacks | Leave a comment

Sorry US; Europeans Listen to Space with GRAVES

In Europe, the GRAVES radar station beams a signal on 143.050 MHz almost straight up to detect and track satellites and space junk. That means you will generally not hear any signal from the station. However, [DK8OK] shows how you can–if you are in Europe–listen for reflections from the powerful radar. The reflections can come from airplanes, meteors, or spacecraft. You can see a video from [way1888] showing the result of the recent Perseid meteor shower.

Using a software-defined radio receiver, [DK8OK] tunes slightly off frequency and waits for reflections to appear in the waterfall. In addition to observing the …read more

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Posted in EME, ionosphere, radio, radio hacks, transmitter | Leave a comment

Crowdsourcing The Study Of An Eclipse’s Effect On Radio Propagation

If you are an American, you’ll probably now find yourself in one of three camps. People who are going to see the upcoming solar eclipse that will traverse your continent, people who aren’t going to see the eclipse, and people who wish everyone would just stop going on incessantly about the damn eclipse.

Whichever of those groups you are in though, there is an interesting project that you can be a part of, an effort from the University of Massachusetts Boston to crowdsource scientific observation of the effect a solar eclipse will have on the upper atmosphere, and in particular …read more

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Posted in atmosphere, Eclipse 2017, news, radio, radio hacks, radio propagation, wwvb | Leave a comment

Amateur Radio Just Isn’t Exciting

As ARRL president, [Rick Roderick, K5UR] spends a significant amount of time proselytising the hobby. He has a standard talk about amateur radio that involves tales gleaned from his many decades as a licence holder, and features QSL cards from rare DX contacts to show how radio amateurs talk all over the world.

He’s delivered this talk countless times, and is used to a good reception from audiences impressed with what can be done with radio. But when he delivered it to a group of young people, as Southgate ARC reports, he was surprised to see a lack of interest …read more

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Posted in amateur radio, ARRL, ham radio, radio, radio hacks | Leave a comment

Rapidly Prototyping RF Filters

RF filters are really just a handful of strategically placed inductors and capacitors. Yes, you can make a 1 GHz filter out of through-hole components, but the leads on the parts turn into inductors at those frequencies, completely ruining the expected results in a design.

The solution to this is microstrip antennas, or carefully arranged tracks and pads on a PCB. Anyone can build one of these with Eagle or KiCad, but that means waiting for an order from a board house to verify your design. [VK2SEB] has a better idea for prototyping PCB filters: use copper tape on blank …read more

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Posted in filter, microstrip, microstrip filter, misc hacks, pcb, radio, RF, rf filter, wireless hacks | Leave a comment

Hackaday Prize Entry: Open Narrowband RF Transceiver

We have so many options when we wish to add wireless control to our devices, as technology has delivered a stream of inexpensive devices and breakout boards for our experimentation. A few dollars will secure you all your wireless needs, it seems almost whatever your chosen frequency or protocol. There is a problem with this boundless availability though, they can often be rather opaque and leave their users only with what their onboard firmware chooses to present.

The Open Narrowband RF Transceiver from [Samuel Žák] promises deliver something more useful to the experimenter: an RF transceiver for the 868 or …read more

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Posted in Hackaday Prize, radio, radio hacks, RF, The Hackaday Prize, transceiver | Leave a comment