Ignoring all of the regulations, band allocations, and “best amateur practices,” there’s no real fundamental difference between the frequencies allocated to the Family Radio Service (FRS), the General Mobile Radio Service (GMRS), the Multi-Use Radio Service (MURS), and the two-meter and 70-centimeter bands allocated to licensed ham radio operators. The radio waves propagate over relatively short distances, don’t typically experience any skip, and are used for similar activities. The only major difference between these (at least in the Americas or ITU region 2) is the licenses you must hold to operate on the specific bands. This means that even though radios are prohibited by rule from operating across these bands, it’s often not too difficult to find radios that will do it anyway.
[Greg], aka [K4HSM], was experimenting with a TIDRADIO H8 meant for GMRS, which in North America is a service used for short-range two-way communication. No exams are required, but a license is still needed. GMRS also allows for the use of repeaters, making it more effective than the unlicensed FRS. GMRS radios, this one included, often can receive or scan frequencies they can’t transmit on, but in this case, the limits on transmitting are fairly easy to circumvent. While it isn’t allowed when programming the radio over Bluetooth, [K4HSM] found that programming it from the keypad directly will allow transmitting on the ham bands and uses it to contact his local two-meter and 70-cm repeaters as a proof-of-concept.
The surprising thing about this isn’t so much that the radio is physically capable of operating this way. What’s surprising is that this takes basically no physical modifications at all, and as far as we can tell, that violates at least one FCC rule. Whether or not that rule makes any sense is up for debate, and it’s not likely the FCC will break down your door for doing this since they have bigger fish to fry, but we’d definitely caution that it’s not technically legal to operate this way.
Like any hobby, amateur radio has no upper bounds on what you can spend getting geared up. Shacks worth tens of thousands of dollars are easy to come by, and we’ll venture a guess that there are hams out there pushing six figures with their investment in equipment. But hands down, the most expensive amateur radio station ever has to be the one aboard the International Space Station.
So what do you need to talk to a $100 billion space station? As it turns out, about $60 worth of stuff will do, as [saveitforparts] shows us in the video below. The cross-band repeater on the ISS transmits in the 70-cm ham band, meaning all that’s needed to listen in on the proceedings is a simple “handy talkie” transceiver like the $25-ish Baofeng shown. Tuning it to the 437.800-MHz downlink frequency with even a simple whip antenna should get you some reception when the ISS passes over.
In our experience, the stock Baofeng antenna isn’t up to the job, so something better like the Nagoya shown in the video is needed. Better still is a three-element Yagi tuned down slightly with the help of a NanoVNA; coupled with data on when the ISS will be within line-of-sight, picking up the near-constant stream of retransmissions from the station as Earth-based hams work it should be a snap — even though [saveitforparts] only listened to the downlink frequency here, for just a bit more of an investment it’s also possible for licensed hams to uplink to the ISS on 145.900 MHz.
For those who want a slightly higher level of difficulty, [saveitforparts] also has some tips on automating tracking with an old motorized mount for CCTV cameras. Pitchfork notwithstanding, it’s not the best antenna tracker, but it has promise, and we’re eager to see how it pans out — sorry. But in general, the barrier to entry for getting into space communications is so low that you could easily make this a weekend project. We’ve been discussing this and other projects on the new #ham-shack channel over on the Hackaday Discord. You should pop over there and check it out — we’d be happy to see you there.
The reports of the death of automotive AM radio may have been greatly exaggerated. Regular readers will recall us harping on the issue of automakers planning to exclude AM from the infotainment systems in their latest offerings, which doesn’t seem to make a lot of sense given the reach of AM radio and its importance in public emergencies. US lawmakers apparently agree with that position, having now introduced a bipartisan bill to require AM radios in cars. The “AM for Every Vehicle Act” will direct the National Highway Transportation Safety Administration to draw up regulations requiring every vehicle operating on US highways to be able to receive AM broadcasts without additional fees or subscriptions. That last bit is clever, since it prevents automakers from charging monthly fees as they do for heated seats and other niceties. It’s just a bill now, of course, and stands about as much chance of becoming law as anything else that makes sense does, so we’re not holding our breath on this one. But at least someone recognizes that AM radio still has a valid use case.
Looks like it’s lights out on Mars for the InSight lander. The solar-powered lander’s last selfie, sent back in April, showed a thick layer of dust covering everything, including the large circular solar panels needed to power the craft. At the time, NASA warned that InSight would probably give up the ghost sometime before the end of the year, and it looks like InSight is sticking to that schedule. InSight sent back what might be its last picture recently, showing the SEIS seismic package deployed on the regolith alongside the failed HP3 “mole” experiment, which failed to burrow into the soil as planned. But one bad experiment does not a failed mission make — it was wildly successful at most everything it was sent there to do, including documenting the largest marsquake ever recorded. As it usually does, NASA has anthropomorphized InSight with bittersweet sentiments like “Don’t cry, I had a good life,” and we’re not quite sure how we feel about that. On the one hand, it kind of trivializes the engineering and scientific accomplishments of the mission, but then again, it seems to engage the public, so in the final rinse, it’s probably mostly harmless.
It’ll be Pi Day when this article goes live, at least for approximately half the globe west of the prime meridian. We always enjoy Pi Day, not least for the excuse to enjoy pie and other disc-shaped foods. It’s also cool to ponder the mysteries of a transcendental number, which usually get a good treatment by the math YouTube community. This year was no disappointment in this regard, as we found two good pi-related videos, both by Matt Parker over at Standup Maths. The first one deals with raising pi to the pi to the pi to the pi and how that may or may not result in an integer that’s tens of trillions of digits long. The second and more entertaining video is a collaboration with Steve Mould which aims to estimate the value of pi by measuring the volume of a molecular monolayer of oleic acid floating on water. The process was really interesting and the results were surprisingly accurate; this might make a good exercise to do with kids to show them what pi is all about.
Remember basic physics and first being exposed to the formula for universal gravitation? We sure do, and we remember thinking that it should be possible to calculate the force between us and our classmates. It is, of course, but actually measuring the attractive force would be another thing entirely. But researchers have done just that, using objects substantially smaller than the average high school student: two 2-mm gold balls. The apparatus the Austrian researchers built used 90-milligram gold balls, one stationary and one on a suspended arm. The acceleration between the two moves the suspended ball, which pivots a mirror attached to the arm to deflect a laser beam. That they were able to tease a signal from the background noise of electrostatic, seismic, and hydrodynamic forces is quite a technical feat.
We noticed a lot of interest in the Antikythera mechanism this week, which was apparently caused by the announcement of the first-ever complete computational model of the ancient device’s inner workings. The team from University College London used all the available data gleaned from the 82 known fragments of the mechanism to produce a working model of the mechanism in software. This in turn was used to create some wonderful CGI animations of the mechanism at work — this video is well worth the half-hour it takes to watch. The UCL team says they’re now at work building a replica of the mechanism using modern techniques. One of the team says he has some doubts that ancient construction methods could have resulted in some of the finer pieces of the mechanism, like the concentric axles needed for some parts. We think our friend Clickspring might have something to say about that, as he seems to be doing pretty well building his replica using nothing but tools and methods that were available to the original maker. And by doing so, he managed to discern a previously unknown feature of the mechanism.
We got a tip recently that JOGL, or Just One Giant Lab, is offering microgrants for open-source science projects aimed at tackling the problems of COVID-19. The grants are for 4,000€ and require a minimal application and reporting process. The window for application is closing, though — March 21 is the deadline. If you’ve got an open-source COVID-19 project that could benefit from a cash infusion to bring to fruition, this might be your chance.
And finally, we stumbled across a video highlighting some of the darker aspects of amateur radio, particularly those who go through tremendous expense and effort just to be a pain in the ass. The story centers around the Mt. Diablo repeater, an amateur radio repeater located in California. Apparently someone took offense at the topics of conversation on the machine, and deployed what they called the “Annoy-o-Tron” to express their displeasure. The device consisted of a Baofeng transceiver, a cheap MP3 player loaded with obnoxious content, and a battery. Encased in epoxy resin and concrete inside a plastic ammo can, the jammer lugged the beast up a hill 20 miles (32 km) from the repeater, trained a simple Yagi antenna toward the site, and walked away. It lasted for three days and while the amateurs complained about the misuse of their repeater, they apparently didn’t do a thing about it. The jammer was retrieved six weeks after the fact and hasn’t been heard from since.
There is a long history of spacecraft carrying ham radio gear, as the Space Shuttle, Mir, and the ISS have all had hams aboard with gear capable of talking to the Earth. However, this month, the ISS started operating an FM repeater that isn’t too dissimilar from a terrestrial repeater. You can see [TechMinds] video on the repeater, below.
The repeater has a 2 meter uplink and a 70 centimeter downlink. While you can use a garden variety dual-band ham transceiver to use the repeater, you’ll probably need a special antenna along with special operating techniques.
Apple, the world’s first trillion-dollar company — give or take a trillion — has built a bit of libertarian cachet by famously refusing to build backdoors into their phones, despite the entreaties of the federal government. So it came as a bit of a surprise when we read that the company may have worked with federal agents to build an “enhanced” iPod. David Shayer says that he was one of three people in Apple who knew about the 2005 program, which was at the behest of the US Department of Energy. Shayer says that engineers from defense contractor Bechtel, seemed to want to add sensors to the first-generation iPod; he was never clued in fully but suspects they were adding radiation sensors. It would make sense, given the climate in the early 2000s, walking down the street with a traditional Geiger counter would have been a bit obvious. And mind you, we’re not knocking Apple for allegedly working with the government on this — building a few modified iPods is a whole lot different than turning masses of phones into data gathering terminals. Umm, wait…
A couple of weeks back, we included a story about a gearhead who mounted a GoPro camera inside of a car tire. The result was some interesting footage as he drove around; it’s not a common sight to watch a tire deform and move around from the inside like that. As an encore, the gearhead in question, Warped Perception, did the same trick bit with a more destructive bent: he captured a full burnout from the inside. The footage is pretty sick, with the telltale bubbles appearing on the inside before the inevitable blowout and seeing daylight through the shredded remains of the tire. But for our money, the best part is the slo-mo footage from the outside, with the billowing smoke and shredded steel belts a-flinging. We appreciate the effort, but we’re sure glad this guy isn’t our neighbor.
Speaking of graphic footage, things are not going well for some remote radio sites in California. Some towers that host the repeaters used by public service agencies and ham radio operators alike have managed to record their last few minutes of life as wildfires sweep across the mountains they’re perched upon. The scenes are horrific, like something from Dante’s Inferno, and the burnover shown in the video below is terrifying; watch it and you’ll see a full-grown tree consumed in less than 30 seconds. As bad as the loss of equipment is, it pales in comparison to what the firefighters face as they battle these blazes, but keep in mind that losing these repeaters can place them in terrible jeopardy too.
