There was a time when one of the perks of having a ham radio in your car (or on your belt) was you could make phone calls using a “phone patch.” In the 1970s, calling someone from inside your parked car turned heads. Now, of course, it is an everyday occurrence thanks to cell phones. But in 1977, cell phones were nowhere to be found. Joseph Sugarman, the well-known founder of JS&A, saw a need and wanted to fill it. So he offered the “PocketCom CB” which was billed as the “world’s smallest citizens band transceiver.” You can see the full-page ad from 1977 below.
Remember that this is from an era when ICs that could operate at 30 MHz were not the norm, so you have to temper your expectations. The little unit was 5.5 in by 1.5 in and less than an inch thick. That’s actually not bad, but you had — optimistically — 100 mW of output power. They claimed the N cell batteries would last two weeks with average use, but we imagine a lot less as soon as you start transmitting. The weight was 5 oz, but we suspect that is without the batteries.
Continue reading “Retro Gadgets: The CB Cell Phone” →
It looks like the Martian winter may have claimed another victim, with reports that Chinese ground controllers have lost contact with the Zhurong rover. The solar-powered rover was put into hibernation back in May 2022, thanks to a dust storm that kicked up a couple of months before the start of local winter. Controllers hoped that they would be able to reestablish contact with the machine once Spring rolled around in December, but the rover remains quiet. It may have suffered the same fate as Opportunity, which had its solar panels covered in dust after a planet-wide sandstorm and eventually gave up the ghost.
What’s worse, it seems like the Chinese are having trouble talking to the Tianwen-1 orbiter, too. There are reports that controllers can’t download data from the satellite, which is a pity because it could potentially be used to image the Zhurong landing site in Utopia Planitia to see what’s up. All this has to be taken with a grain of dust, of course, since the Chinese aren’t famously transparent with their space program. But here’s hoping that both the rover and the orbiter beat the odds and start doing science again soon.
Continue reading “Hackaday Links: January 15, 2023” →
Ever wonder what makes a cellphone’s operating system secure, or what that app you just installed is saying about you behind your back? In a brand new video series, [Jiska] gives us a peek into different topics in smartphone software reverse engineering.
For instance, her latest video, embedded below takes us through some steps to poke at Apple’s RTKit OS, which is the realtime OS that runs inside most of their peripheral devices, including AirPods, but also on their bigger devices too. We don’t know much about RTKit OS, but [Jiska]’s trick in this video is to get a foothold by looking through two different RTKit OS versions and noting which symbols are common — these are probably OS function names. Now you’ve got something to look for.
Each of the videos is short, to the point, and contains nice tips for perhaps the intermediate-to-advanced reverser who is looking to get into phones. Heck, even if you’re not, her demonstrations of the Frida dynamic tracing tool are worth your time.
And if you want a longer introduction into the internals of cellphones, we heartily recommend her talk, “All Wireless Stacks Are Broken“.
Continue reading ““Reversing Shorts” Demystify Phone Security” →
Many of us hackers have a longing for numpad-adorned mobile phones. We also have a shared understanding that, nowadays, such a phone has to be open and Linux-powered. Today’s project, Notkia, is the most promising and realistic effort at building a keypad phone that fits our requirements. Notkia is a replacement board for Nokia 168x series phones, equipped with an improved display, USB-C, WiFi, Bluetooth, and LoRa — and [Reimu NotMoe] of [SudoMaker] tells us this project’s extensive story.
The Notkia effort started over two years ago, because of [Reimu]’s increasing dislike for modern smartphones — something every hacker is familiar with. Her first-hand experience with privacy violations and hackability limitations on Android phones is recounted in detail, leading to a strong belief that there are fundamental problems with phones available nowadays. Building new hardware from the ground up seems to be the way forward. Two years later, this is exactly what we got!
Continue reading “Notkia: Building An Open And Linux-Powered Numpad Phone” →
The SDR revolution has completely changed the way radio enthusiasts pursue their hobby, but there is still a space for the more traditional scanning receiver. If you are an American, have you ever noticed that it has a gap in its coverage between 800 and 900 MHz? The curious reason for this is explored by [J. B. Crawford], and it’s a tale of dusty laws relating to a long-gone technology, remaining on the books only because their removal requires significant political effort.
What we might today refer to as “1G” phones used an entirely analogue transmission scheme, with an easily-receivable FM carrier for the voice and extremely low-bandwidth bursts of serial data only for the purposes of managing the call. Listening to these calls was an illegal activity, but for those with the appropriate scanners it became a voyeuristic hobby within a hobby. It even made the world news via the pages of the gossip sheets, when (truthfully or not) it was credited for the leak of a revealing and controversial conversation involving Diana Princess of Wales.
This caused significant worry to the cellular phone companies who understandably didn’t want their product to become associated with insecurity. Thus they successfully petitioned the US Congress to include a clause restricting the capabilities of scanning receivers into another telecoms-related Act, and here we are three decades later with analogue phones a distant memory and the law still on the books. It may be ancient and unnecessary but there is neither the will nor the resources to remove it, so it seems destined to become one of those curious legal oddities that remains on the books for centuries. Whether an RTL-SDR breaks it is something we’ll leave for the lawyers, but the detail in the write-up makes it well worth a read.
Header image: krystof.k (Twitter) & nmuseum, CC BY-SA 3.0.
We think of the mobile phone — well, what we would call a cell phone — as something fairly modern. Many of us can still remember when using a ham radio phone patch from your parked car would have people staring and murmuring. But it turns out in the late 1940s, Bell Telephone offered Mobile Telephone Service (MTS). It was expensive and didn’t work as well as what we have now, but it did let you make or receive calls from your automobile. After the break, you can see a promotional film about MTS.
The service rolled out in St. Louis in the middle of 1946. The 80-pound radios went in the trunk with a remote handset wired to the dashboard. At first, there were only 3 channels but later Bell added 29 more to keep up with demand. An operator connected incoming and outbound calls and if three other people were using their mobile phones, you were out of luck.
Continue reading “Retrotechtacular: Mobile Phones 1940s Style” →
Mobile phones are the photography tool for most of us, but they are a blunt tool. If you love astrophotography, you buy a DSLR and a lens adapter. Infrared photography needs camera surgery or a special unit. If you want to look closer to home, you may have a microscope with a CCD. Your pocket computer is not manufactured for microscopy, but that does not mean it cannot be convinced. Most of us have held our lens up to the eyepiece of some binoculars or a microscope, and it sort of works, but it is far from perfect. [Benedict Diederich] and a team are proving that we can get darn beautiful images with a microscope, a phone holder, and some purpose-built software on an Android phone with their cellSTORM.
The trick to getting useful images is to compare a series of pictures and figure out which pixels matter and which ones are noisy. Imagine someone shows you grainy nighttime footage from an outdoor security camera. When you pause, it looks like hot garbage, and you can’t tell the difference between a patio chair and a shrubbery. As it plays, the noisy pixels bounce around, and you figure out you’re looking at a spruce bush, and that is roughly how the software parses out a crisp image. At the cost of frame rate, you get clarity, which is why you need a phone holder. Some of their tests took minutes, so astrophotography might not fare as well.
We love high-resolution pictures of tiny things and that isn’t going to change anytime soon.
Thank you [Dr. Nicolás De Francesco] for the tip.