shielding

5 Articles

Shielding A Cheap RTL-SDR Stick

June 29, 2022 by 22 Comments

Even though not every Hackaday reader is likely to be a radio enthusiast, it’s a fair guess that many of you will have experimented with an RTL-SDR USB dongle by now. These super-cheap devices are intended for digital TV reception and contain an RTL2832 chip, which with the proper software, can be pushed into service as a general purpose software defined radio receiver. For around $10 USD they’re fantastic value and a lot of fun to play with, even if they’re not the best radio ever. How to improve the lackluster performance? One of the easiest and cheapest ways is simply to shield it from RF noise, which [Alan R] has done with something as mundane as a tubular fizzy orange tablet container.

This is probably one of the simpler hacks you’ll see on this site, as all it involves is making an appropriate hole in the end of the tube and shielding the whole with some aluminium foil sticky tape. But the benefits can be seen immediately in the form of reduced FM broadcast band interference, something that plagues the cheaper dongles.

Perhaps the value in this hack aside from how easy it is on a cheap dongle is that it serves to remind us some of the benefits of paying a little extra for a better quality device. If you’d like to know more about RTL-SDR improvements, it’s a topic we covered in detail back in 2019 when we looked at seven years of RTL-hackery.

Building A Hardware Store Faraday Cage

September 26, 2018 by 76 Comments

Most Hackaday readers are no doubt familiar with the Faraday cage, at least in name, and nearly everyone owns one: if you’ve ever stood watching a bag of popcorn slowly revolve inside of a microwave, you’be seen Michael Faraday’s 1836 invention in action. Yet despite being such a well known device, the average hacker still doesn’t have one in their arsenal. But why?

It could be that there’s a certain mystique about Faraday cages, an assumption that their construction requires techniques or materials outside the realm of the home hacker. While it’s true that building a perfect Faraday cage for a given frequency involves math and careful attention to detail, putting together a simple model for general purpose use and experimentation turns out to be quick and easy.

As an exercise in minimalist hacking I recently built a basic Faraday cage out of materials sourced from Home Depot, and thought it would be interesting to not only describe its construction but give some ideas as to how one can put it to practical use in the home lab. While it’s hardly a perfect specimen, it clearly works, and it didn’t take anything that can’t be sourced locally pretty much anywhere in the world.

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Military Surplus Repurposed For High Energy Physics

December 21, 2017 by 8 Comments

Performing high-energy physics experiments can get very expensive, a fact that attracts debate on public funding for scientific research. But the reality is that scientists often work very hard to stretch their funding as far as they can. This is why we need informative and entertaining stories like Gizmodo’s How Physicists Recycled WWII Ships and Artillery to Unlock the Mysteries of the Universe.

The military have specific demands on components for their equipment. Hackers are well aware MIL-SPEC parts typically command higher prices. That quality is useful beyond their military service, which lead to how CERN obtained large quantities of a specific type of brass from obsolete Russian naval ordnance.

The remainder of the article shared many anecdotes around Fermilab’s use of armor plate from decommissioned US Navy warships. They obtained a mind-boggling amount – thousands of tons – just for the cost of transport. Dropping the cost of high quality steel to “only” $53 per ton (1975 dollars, ~$250 today) and far more economical than buying new. Not all of the steel acquired by Fermilab went to science experiments, though. They also put a little bit towards sculptures on the Fermilab campus. (One of the few contexts where 21 tons of steel can be considered “a little bit”.)

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Fixing The Terrible Range Of Your Cheap NRF24L01+ PA/LNA Module

May 31, 2016 by 66 Comments

nRF24L01+ PA/LNA module specs look great on paper. Wireless communication up to 1000m in a small package readily available from a variety of cheap sources in China? The hard work of software connectivity already done by a variety of open source projects? Sounds great! But if you mashed BUY and are getting maybe 1% of that range, don’t worry because thanks to these clear directions, they can be fixed.

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DIY RFID Shielded Wallet Keeps Data Thieves At Bay

September 22, 2011 by 39 Comments

diy_rf_shielded_wallet

[Serge] was in search of a new wallet, but he was concerned about ne’er do wells with RFID readers stealing his data. He could have gone out to the store and plunked down $20-$30 for a shielded walled, but where’s the fun in that? Instead, he decided to make his own.

Using Kevlar-Nomex fabric, he laid out the general structure for his wallet. This ultra-strong fabric has a breaking strength of 500lbs, but blocking RF isn’t exactly its forte. To provide some electromagnetic shielding, [Serge] added a nice uniform layer of silver epoxy to the Kevlar, which carries an added bonus of strengthening the material. He fired up the sewing machine, adding a nylon strip to the exterior of the wallet for reinforcement, then he worked on forming the bill pouch and card holders.

The final result is a plain yet incredibly rugged wallet that’s sure to keep his various RFID-enabled cards safe. We really dig how unassuming the wallet is – no flash, all function. Nice job, we’ll take one!