Radio – Page 45 – WindowsTechs.com

Radio and Phone Speaker has Style

Posted on February 23, 2017 by Al Williams

Building a crystal radio isn’t exactly rocket science. Some people who build them go for pushing them technically as far as they can go. Others, like [Billy Cheung], go for style points. The modular radio and phone speaker looks like it came out of the movie Brazil. The metallic gramophone-like speaker horn adds to the appeal and mechanically amplifies the sound, too.

The video (see below) isn’t exactly a how-to, but if you watch to the end there is enough information that you could probably reproduce something at least similar. There are actually several horns. One is made from copper, …read more

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A Real Star Trek Communicator Badge

Posted on February 21, 2017 by Adam Fabio

Star Trek has never let technology get in the way of a good story. Gene Roddenberry and the writers of the show thought up some amazing gadgets, from transporters to replicators to the warp core itself. Star Trek: The Next Generation brought us the iconic communicator badge. In 1987, a long-range radio device which could fit in a pin was science fiction. [Joe] is bringing these badges a bit closer to the real world with his entry in the 2017 Hackaday Sci-Fi Contest.

The first problem [Joe] dealt with was finding a radio which could run from watch batteries, and …read more

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An Overview Of The Dreaded EMC Tests

Posted on February 20, 2017 by Jenny List

There is one man whose hour-long sessions in my company give me days of stress and worry. He can be found in a soundless and windowless room deep in the bowels of an anonymous building in a town on the outskirts of London. You’ve probably driven past it or others like it worldwide, without being aware of the sinister instruments that lie within.

The man in question is sometimes there to please the demands of the State, but there’s nothing too scary about him. Instead he’s an engineer and expert in electromagnetic compatibility, and the windowless room is a metal-walled …read more

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World’s Thinnest Morse Code Touch Paddle

Posted on February 18, 2017 by Elliot Williams

Morse code enthusiasts can be picky about their paddles. After all, they are the interface between the man and the machine, and experienced telegraphers can recognize each other by their “hands”. So even though [Edgar] started out on a cheap, clicky paddle, it wouldn’t be long before he made a better one of his own. And in the process, he also made what we think is probably the thinnest paddle out there, being a single sheet of FR4 PCB material and a button cell battery. This would be perfect for a pocketable QRP (low-power) rig. Check it out in action …read more

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Baofeng Handy Talkie Meets GNU Radio

Posted on February 12, 2017 by Al Williams

There was a time when just about every ham had a pricey VHF or UHF transceiver in their vehicle or on their belt. It was great to talk to friends while driving. You could even make phone calls from anywhere thanks to automatic phone patches. In 1980 cell phones were uncommon, so making a call from your car was sure to get attention.

Today, ham radio gear isn’t as pricey thanks to a flood of imports from companies like Baofeng, Jingtong, and Anytone. While a handheld transceiver is more of an impulse buy, you don’t hear as much chat and …read more

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More Power: Powel Crosley and the Cincinnati Flamethrower

Posted on February 6, 2017 by Dan Maloney

We tend to think that there was a time in America when invention was a solo game. The picture of the lone entrepreneur struggling against the odds to invent the next big thing is an enduring theme, if a bit inaccurate and romanticized. Certainly many great inventions came from independent inventors, but the truth is that corporate R&D has been responsible for most of the innovations from the late nineteenth century onward. But sometimes these outfits are not soulless corporate giants. Some are founded by one inventive soul who drives the business to greatness by the power of imagination and …read more

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Books You Should Read: Making A Transistor Radio

Posted on February 3, 2017 by Jenny List

When a Hackaday article proclaims that its subject is a book you should read, you might imagine that we would be talking of a seminal text known only by its authors’ names. Horowitz and Hill, perhaps, or maybe Kernigan and Ritchie. The kind of book from which you learn your craft, and to which you continuously return to as a work of reference. Those books that you don’t sell on at the end of your university career.

So you might find it a little unexpected then that our subject here is a children’s book. Making A Transistor Radio …read more

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Books You Should Read: Making A Transistor Radio

Posted on February 3, 2017 by Jenny List

So you might find it a little unexpected then that our subject here is a children’s book. Making A Transistor Radio …read more

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Everyone Should Build At Least One Regenerative Radio Receiver

Posted on February 1, 2017 by Jenny List

When we build an electronic project in 2016, the chances are that the active components will be integrated circuits containing an extremely large amount of functionality in a small space. Where once we might have used an op-amp or two, a 555 timer, or a logic gate, it’s ever more common to use a microcontroller or even an IC that though it presents an analog face to the world does all its internal work in the digital domain.

There was a time when active components such as tubes or transistors were likely to be significantly expensive, and integrated circuits, if …read more

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PCB Design Guidelines to Minimize RF Transmissions

Posted on January 26, 2017 by Bob Baddeley

There are certain design guidelines for PCBs that don’t make a lot of sense, and practices that seem excessive and unnecessary. Often these are motivated by the black magic that is RF transmission. This is either an unfortunate and unintended consequence of electronic circuits, or a magical and useful feature of them, and a lot of design time goes into reducing or removing these effects or tuning them.

You’re wondering how important this is for your projects and whether you should worry about unintentional radiated emissions. On the Baddeley scale of importance:

Pffffft – You’re building a one-off project that