No Ham License? Listen Anyway In Your Browser

Full disclosure: ham radio isn’t for everyone, and there are many different facets to it. What appeals to one person might bore another to death. One area of ham radio that has changed a lot in the last few years is more or less local and typically mobile operation on VHF or UHF. Not long ago, hams used HTs (walky-talkies or handi-talkies) or mobile radios via repeaters to talk to each other and — the golden prize back then — make phone calls from their cars. Cell phones have made that much less interesting, but there is still an active community of operators talking on repeaters. However, the traffic has gone digital, the Internet is involved, and people with inexpensive, low-powered radios can talk to each other across the globe. This is nothing new, of course. However, having digital services means that operators with special interests can congregate in what amounts to radio chat rooms organized by region or topic.

There’s a long history of people listening to ham radio conversations with shortwave radios, SDRs, and scanners. But with so much activity now carried on the Internet, you can listen in using nothing more than your web browser or a phone app. I’ll show you how. If you get interested enough, it is easy enough to get your license. You don’t need any Morse code anymore, and a simple Technician class license in the United States is all you need to get going.

A Quick DMR Primer

There are several digital ham networks around and like real networks, you can have different physical transport layers and then build on top of that. For the purposes of this post, I’m going to focus on DMR (digital mobile radio) on the Brandmeister network which is very large and popular ham network. You won’t need a license nor will you need to sign up for anything as long as you are content to just listen.

Continue reading “No Ham License? Listen Anyway In Your Browser”

Using The ESP8266 For Low-Cost Fault Injection

As a general concept, fault injection is a technique that studies how a system reacts to unusual or unexpected external forces. The idea is that, if you can trigger a glitch at the precise moment, you might be able to use that to your advantage in disabling security features or otherwise gaining further access to the device in question. In the hardware world, this could be achieved by fiddling with the power going into the device, or subjecting it to extreme temperatures.

We’ve covered voltage glitching attacks on these pages in the past, but most of the tools used are fairly expensive if you’re not doing this kind of thing professionally. Luckily for us, [Aditya Patil] has developed a fault injection tool that can run on a standard ESP8266 development board. Obviously it’s not as capable as a bespoke device costing hundreds of dollars, but if you just want to experiment with the concept, it’s a fantastic way to wrap your head around it all.

Continue reading “Using The ESP8266 For Low-Cost Fault Injection”

Nice PDF, But Can It Run DOOM? Yup!

DOOM is a classic game to implement on a variety of platforms, but doompdf by [ading2210] is one we didn’t see coming. It runs a bit slow and controls are a little awkward but it does run. Entirely within a PDF file, at that.

How is this possible? PDFs are technically capable of much more than just displaying static content, and support JavaScript with their own library of functions. Adobe Acrobat implements the full spec, but modern web browsers implement at least a subset of the functionality in a sandboxed JavaScript runtime environment. Input and output are limited to things one might expect from a fancy PDF form (text input boxes, clickable buttons, things of that nature) but computation-wise, just about anything goes.

Continue reading “Nice PDF, But Can It Run DOOM? Yup!”