Collaborate Disseminate
The radio frequency world is full of mysteries, some of which seem to take a lifetime to master. And even then, it seems like there’s always something more to learn, …read more Continue reading The Perils of Return Path Gaps
Another week, another exploit against an air-gapped computer. And this time, the attack is particularly clever and pernicious: turning a GPU into a radio transmitter.
The first part of [Mikhail Davidov] and [Baron Oldenburg]’s article is a review of some of the basics of exploring the RF emissions of computers …read more
Continue reading GPU Turned Into Radio Transmitter To Defeat Air-Gapped PC
If you’re going to fail, you might as well fail ambitiously. A complex project with a lot of subsystems has a greater chance of at least partial success, as well as providing valuable lessons in what not to do next time. At least that’s the lemonade [Josh Johnson] made from …read more
Continue reading Fail of the Week: Ambitious Vector Network Analyzer Fails To Deliver
We usually reserve the honor of Fail of the Week for one of us – someone laboring at the bench who just couldn’t get it together, or perhaps someone who came perilously close to winning a Darwin Award. We generally don’t highlight commercial products in FotW, but in the case of this substandard RF signal generator, we’ll make an exception.
We suppose the fail-badge could be pinned on [electronupdate] for this one in a way; after all, he did shell out $200 for the RF Explorer signal generator, which touts coverage from 24 MHz to 6 GHz. But in true …read more
Continue reading Fail of the Week: How Not to Design an RF Signal Generator
At this point it’s pretty well-known that you can tack a long wire to the Raspberry Pi’s GPIO, install some software, and you’ve got yourself the worlds easiest pirate FM radio station. We say that it’s a “pirate” station because, despite being ridiculously easy to do, broadcasting on these frequencies without a license is illegal. Even if you had a license, the Raspberry Pi with a dangling bit of wire will be spewing out all kinds of unintentional noise, making it a no-go for any legitimate purposes.
In an effort to address that issue, [Naich] has written up a couple …read more
Cheap DC-DC converters have been a boon on the hobbyist bench for a while now, but they can wreak havoc with sensitive circuits if you’re not careful. The problem: noise generated by the switch-mode supply buried within them. Is there anything you can do about the noise?
As it turns out, yes there is, and [Shahriar] at The Signal Path walks us through a basic circuit to reduce noise from DC-DC converters. The module under the knife is a popular buck-boost converter with a wide input range, 0-32 VDC output at up to 5 amps, and a fancy controller with …read more
If you buy an amateur transceiver cheap enough to make a reasonable grab bag gift or stocking stuffer, you get what you pay for. And if this extensive analysis of cheap radios is any indication, you get a little more than you pay for in the spurious emissions department.
Amateur radio in the United States is regulated by the FCC’s Part 97 rules with special attention given to transmitter technical specifications in Subpart D. Spurious emissions need to be well below the mean power of the fundamental frequency of the transmitter, and [Megas3300] suspected that the readily available Baofeng UV-5RA …read more
Continue reading Measuring Spurious Emissions of Cheap Handheld Transceivers
