Category Archives: radio

Dust Off Those AM Radios, There’s Something Good On!

If you are into vintage electronics or restoring antique radio equipment you may be very disappointed with the content offerings on AM broadcast radio these days. Fortunately there is a way to get around this: build your own short-range AM broadcast station and transmit curated content to your radios (and possibly your neighbors). There are several options for creating your own short-range AM broadcast station, and this gives you something fun to tune into with your vintage radio gear.

Antique Radios See Daily Use Once More

We see a ton of antique radios turned into Internet radios. Perhaps this is …read more

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Posted in am radio, amplitude modulation, Hackaday Columns, internet radio, mp3 player, playlist, radio, radio hacks, transmitter | Leave a comment

Radio Amateuring Like It’s 1975

It was a tweet from an online friend in the world of amateur radio, featuring a transmitter design published in Sprat, the journal of the G-QRP club for British enthusiasts of low-power radio. The transmitter was very simple, but seriously flawed: keying the power supply line would cause it to exhibit key clicks and frequency instability. It would probably have been far better leaving the oscillator connected full-time and keying the supply to the amplifier, with of course a suitable key click filter.

We’ve all probably made projects that get the job done at the expense of a bit …read more

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

Skin (Effect) in the Game

We love to pretend like our components are perfect. Resistors don’t have capacitance or inductance. Wires conduct electricity perfectly. The reality, though, is far from this. It is easy to realize that wire will have some small resistance. For the kind of wire lengths you usually encounter, ignoring it is acceptable. If you start running lots of wire or you are carrying a lot of current, you might need to worry about it. Really long wires also take some time to get a signal from one end to the other, but you have to have a very long wire to …read more

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Posted in ac, Engineering, hackaday 101, Hackaday Columns, radio, RF, skin effect | Leave a comment

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