One of the more popular trends in the ham radio community right now is operating away from the shack. Parks on the Air (POTA) is an excellent way to take a mobile radio off-grid and operate in the beauty of nature, but for those who want to take their rig to more extreme locations there’s another operating award program called Summits on the Air (SOTA) that requires the radio operator to set up a station on a mountaintop instead. This often requires lightweight, low-power radios to keep weight down for the hike, and [Dan] aka [AI6XG] has created a radio from scratch to do just that.
[Dan] is also a vacuum tube and CW (continuous wave/Morse code) operator on top of his interest in summiting various mountains, so this build incorporates all of his interests. Most vacuum tubes take a lot of energy to operate, but he dug up a circuit from 1967 that uses a single tube which can operate from a 12 volt battery instead of needing mains power, thanks to some help from a more modern switch-mode power supply (SMPS). The SMPS took a bit of research, though, in order to find one that wouldn’t interfere with the radio’s operation. That plus a few other modern tweaks like a QCX interface and a switch to toggle between receive to transmit easily allows this radio to be quite versatile when operating while maintaining its portability and durability when summiting.
For those looking to replicate a tube-based radio like this one, [Dan] has made all of the schematics available on his GitHub page. The only other limitation to keep in mind with a build like this is that it tends to only work on a very narrow range of frequencies without adding further complexity to the design, in this case within the CW portion of the 40-meter band. But that’s not really a bad thing as most radios with these design principles tend to work this way. For some other examples, take a look at these antique QRP radios for operating using an absolute minimum of power.
[Allen Millyard] is a premier British motorcycle builder. In these circles he is widely regarded and his custom motorcycles are nearly world-famous. But when his son took up downhill mountain biking, he decided to put his skills building a different type of vehicle. This is the Millyard MR001, one of the most unique mountain bikes ever built thanks to some design choices that solve many problems otherwise inherent in bicycles.
Perhaps the most immediately striking design of this bike is the aluminum space frame, a lightweight but extremely strong frame necessary for the high speeds and stresses of downhill mountain biking. Upon closer inspection, however, the sealed drivetrain warrants further inspection. Unlike most mountain bikes with gears, this one eliminates the typical derailleur which hangs below the rear gears. The gears are instead above the pedals in front of the rear tire, are completely sealed eliminating the maintenance requirements of a typical bike, and are designed in such a way that they can be shifted without the bike moving.
Despite the bike being built in 2007, it still includes plenty of features that still aren’t widely adopted in mountain biking. It’s also nearly completely silent thanks to the custom drivetrain, and [Allen] reports that it still sneaks up on other mountain bikers as a result. This is essentially the opposite problem of another bike we’ve seen around.
Continue reading “Motorcycle Builder Makes Downhill Mountain Bike”
On today’s edition of ‘don’t try this at home,’ we’re transported to Russia to see [Igor Negoda]’s working jet bicycle.
This standard mountain bike comes equipped with a jet engine capable of 18kg of thrust, fixed to the frame under the seat with an adjustable bracket to change it’s angle as needed. A cell phone is zip-tied to the frame and acts as a speedometer — if it works, it’s not stupid — and an engine controller displays thrust, rpm and temperature. A LiPo battery is the engine’s power source with a separate, smaller battery for the electronics. The bike is virtually overgrown with wires and tubes that feed the engine, including an auxiliary fuel tank where a water bottle normally resides. Where’s the main fuel tank? In [Negoda]’s backpack, of course.
It certainly kicks up a mean dust cloud and makes a heck of a racket but the real question is: how fast does it go? From the looks of the smartphone, 72 km/h, 45 mph, or 18 rods to the hogshead.
Continue reading “A Jet Engine On A Bike. What’s The Worst That Could Happen?”
This bicycle has no pedals and really nothing that resembles a seat. It’s not so much a way to get around as it’s a way to get down. Down from the mountain, and down low to the pavement. This is a gravity bike built by the guys at S.I.N. Cycles.
The frame is a long triangle which stretches the wheel base to make room for the rider. After getting the layout just right and welding the frame together they added the rather unorthodox building step of pouring molten lead into the hollow frame tube. This bike is used to descend a mountain road with the force of gravity, so the extra weight will help pull it just a bit faster. There’s one thing you’ll want to make sure is working before you climb aboard — the single front brake which you’ll need when coming into the curves. Check out some ride footage on this thing in the video after the break.
Continue reading “Gravity Bike”
[Willem] has a friend that wanted to take a GPS datalogger up an unclimbed mountain the wilds of Kyrgyzstan. The GPS logger built for the expedition made it to the summit of Eggmendueluek, but it didn’t work the whole way up. Since the logger came back to London, [Willem] was able to do a complete teardown and failure analysis.
The data logger was built around a Jeenode with a GPS unit and MicroSD card reader added on. A few breakout boards were made and two of these bad boys were ensconced in water and dust proof enclosures. Powered by four AA batteries, the data loggers were able to handle the rigorous testing of being thrown down a staircase and also the harsh temperatures of London. Things changed in the wilds of Kyrgyzstan, though.
The data retrieved from the mountaineering expedition wasn’t the greatest – a few wires came loose after being thrown into the back of a Russian truck and jostled around. The AA batteries only powered the data loggers for three days, compared to the 12 day battery life in London. There are a few improvements needed for the next trip – some thermal insulation and not using solid core wire – but not that [Willem] has figured out the bugs he’s ready for his friend’s next expedition.
Why risk frostbite and altitude sickness when you can marvel at the view from atop your own mountain climbing game?
[Jeff] built this delightful piece which you can see in action after the break. he combined several very simple ideas and he did it really well. The climbers are both mechanical. They grip the mountain’s face (which is covered with of carpet) with a tack pointed downward on the end of each limb. Their motion is provided by two tiny servos that make up the body of the climber. The two potentiometers in each controller directly affect the movement of the top and bottom limbs. The game plays music during the contest, and precisely detects a winner by sensing when an arm comes in contact with the metal snow cap at the summit.
Obviously weight was an issue during the design process. After some hemming and hawing [Jeff] decided to tether the climbers in order to avoid rolling a battery into each. But he overcame the issue with weighted cable management on the inside of the mountain.
Continue reading “Head-to-head Mountain Climbing From The Safety Of Your Game Room”
So you hear that someone is building a clock that will run for 10,000 years and you think ‘oh, that’s neat’. Then you start looking into it and realize that it’s being built on a mountain-sized scale in a remote part of the US and things start to get a bit strange. As much as it might sound like a Sci-Fi novel (or some creative trolling), the Long Now Foundation is in the process of building and installing a clock that will chime once per year for the next ten millennia.
The clock, currently under construction will be over 200 feet tall, residing in a shaft drilled in a limestone mountain in West Texas. The allusion to [Indian Jones] sprung to mind when we read that the shaft will be drilled from the top down, then have a shaft with a robot arm installed to mill a spiral staircase into the stone walls. And this isn’t the only clock planned; a second site in Nevada has already been purchased.
There are a lot of interesting features, not the least of them is a ‘chime engine’ that plays a unique tune each year that will never be repeated again. [Alex] sent us the original tip to a Wired article that covers the project in incredible detail. But we also found a SETI talks video that runs for an hour. You’ll find that embedded after the break.
Continue reading “10,000 Year Clock Sounds Like An Indiana Jones Flick – Makes Us Wonder If We’re Being Trolled”