Even if it was a quarter million bucks, it would quickly pay itself off. Keeping a taxi car available and operating 24/7 is a big deal for operational costs. $25/hour on a $250k device is a recovered in just over a year. It’s all profit after that.

You’re not off the mark. Honestly not a bad overview to squeeze into a few sentences. Here’s some extra detail for those who remain more curious.

The circuit complexity reduction happens by changing the math behind the radio signal. Much like how you can describe a vector in cartesian coordinates (a point in x, y) or in polar coordinates (a point in angle and length), choosing how to represent the radio math allows for different techniques to arrive in the same answer. That’s what the author did: he picked a polar modulating scheme over a quadrature modulation scheme. (Note, there are even more mathy ways to modulate a radio signal, but those are what the author is presenting to us.)

The author’s choice avoids generating unwanted frequencies that must be filtered out before amplifying. That’s components on the board that don’t need to be designed nor exist. A solid win.

The drawback? Polar modulation is non-linear in frequency space. What that means is certain frequencies are over-represented and others are under-represented. Imagine playing notes on a piano where some keys are very loud and others you could hardly hear them. That’s the unwanted non-linearity.

Herein lies the trick: what’s bad can be turned into good. Power amplifiers typically need to be linear. Imagine a piano that works fine but the auditorium’s loud speakers make it sound terrible. Those loud speakers would be a non-linear amplifier. The trick is that it’s possible to match the modulator’s non-linear behavior with a power amplifier’s non-linear behavior to end up with a clean signal! A non-linear piano and a non-linear loud-speaker can produce beautiful music! This engineering trick unlocks all kinds of non-linear power amplifier architectures (that’s the “C/E/F” described in the article) which are drastically more energy efficient than linear ones (linear designs max out around 65% efficient).

Given the username, I’d say that is the case: https://terptheatre.org/

"TerpTheatre is both a source of information about theatre interpreting and a tradition of theatre interpreters in the shadowed strategy. "

I’m unconvinced. The LBS can still work on Buffalo bikes. They can still repair tubes, true wheels, fix pedals, replace spokes, fix chains, change brake pads, etc. They may not have unique parts, like the AK2 freewheel, but it’s far from being unable to repair most bicycle failures.

I think Evan found an upset businessman who’s in the business of selling Black Mambas. They’re in that same situation as a local doctor that’s been displaced by Doctors Without Borders. And they’re upset that they have to compete with WBR. The complaint is understandable yet it doesn’t absolve them of their own failures.

No bicycle donation program is going to survive on a single LBS or two near a city. If I were to buy a kid a Black Mamba and it breaks down, then the kid has to take it into the city to repair it at that one shop with high repair prices. What’s far more likely is the kid will stop using the bike and sell it. Kids-in-school objective failed.

Note, this is also why WBR only operates in places where there is insufficient bicycle support. There’s no need for WBR to donate and sell bikes if there’s already a healthy local bicycle market. You can’t buy a Buffalo Bicycle and WBR doesn’t want you to have one. Instead go buy a Surley or a SOMA or a Rivendell. We have a robust LBS network. WBR operates where there’s nothing.

And, IMHO, the Black Mamba isn’t a great rural bicycle. It’ll work but it’s far from ideal. By donating to WBR, I know it’s the best bicycle that will go to some kid. I know that it’ll survive long enough for that kid’s few more years of school. I know that it’ll be strong enough to be passed down to their little brother or sister. And I know their village has a dude with a wrench to fix a flat and adjust a pedal. Such robustness is worth the extra $50 over a Black Mamba.

I’m not a fan of this article, mostly because Evan Christenson contemplates the darker side of charities working in underdeveloped countries without actually exploring them beyond criticizing WBR. It’s, likely unintentional, FUD propaganda.

It should not be a shock to find out that charities have overhead and many of them have unfortunate side effects. For example, Evan brings up Doctors Without Borders as a charity with lower overhead and a leader less compensated. That’s true, but did you also know they sell your personal information when you donate to them? That’s part of how they lower their costs. Also they provide doctor services for free. What does that do to the doctors who are there trying to make a meager living? DWB is undermining what little medical infrastructure the country has.

Is that a bad thing? Is it a good thing? That depends on you, the donor’s, perspective. Selling my data to provide more doctor is fine with me. Same with undermining the countries’ medical market because it’s a temporary thing and usually in a crisis where not providing help is definitively worse.

I’ll continue donating to WBR because their expense ratio is acceptable, even good, for physical good imports given the shipping overhead (aka bribes) in Africa. Admim is ~15% and fundraising is ~23%. Everything else goes into the bicycle and into families with kids who cannot afford one. That’s a lower margin than buying just about any good from your local shops, and it’s lower than many other charities working in Africa!

I upgraded my license when my grandfather had to move in with my parents so I coul help him setup a smaller shack and assist in operating the radio with him. He deeply appreciated the family time, and I’m sure your Uncle wouldn’t mind spending time with you too.

For whatever it’s worth, these web interfaces are great at listening and cost nothing. Ask him to help you operate (finding signals and how to listen to them) using a KiwiSDR online. If you find out he’s also having fun, then perhaps look into remote radio station equipment. There’s a wide selection of transmitting capable SDRs, like FlexRadio, and DIY solutions (e.g. https://www.remotetx.net/). You can even rent remote operation time with incredibly nice hardware in amazing locations (e.g. https://www.remotehamradio.com/). Perhaps he’ll be come interested in another side of ham radio that he hasn’t done before either, like working satellite passes. That doesn’t take more than one nice, or two very cheap, handheld radios and a small handheld yagi.

Ham radio can be used as voice chat with friends, but that would be a pretty limited view of it. Here’s some things that a Discord Voice Chat cannot do that radio can:

• Chat without internet (e.g. places without cell towers).
• Chat without voice. (digital communications of all kinds; email/text, keyboard-to-keyboard, pictures, etc).
• To build an internet (e.g. building WiFi meshes with extra power [AREDN], AX.25 packet, WinLink).
• Used as a tool during emergencies (see ARES/RACES/CERT).
• Chat completely randomly (it’s just one big discord channel, but you can only hear some people).
• Chasing the challenge of unusual radio propagation (earth-moon-earth, meteor bounce, tropospheric ducting, aurora).
• Chasing the challenge of collecting the most point-to-point contacts (contests).
• Chasing the challenge of difficult radio propagation (microwave links).
• Constructing and using radios that you cannot buy off the shelf parts with (usually with those funny microwave guys).
• Higher power versions of things unlicensed folks cannot do (RC toys, Meshtastic/LoraWAN, WiFi, etc).
• Historical preservation (restoring old radios, keeping ship-shore coastal stations running [e.g. Maritime Radio Historical Society]).
• Conducting scientific experiments (HamSCI, and I conducted one listening to the ionosphere during the recent total eclipse).
• Building and controlling satellites (AMSAT).

And there’s even more. The way to view ham radio is the government grants you a license to operate on many pieces of radio spectrum so long as you can show your technical ability to not cause harm (interference, safety, and things that will prevent you from blowing up your radio as well as find success in using it). What you do with that spectrum is up to you!

The brands mentioned here (Topeak, Silca, and Park Tools) all have rebuild kits and they’ve been around for a long time. I wouldn’t hesitate buying any of their models.

I’ve been using a Topeak Joeblow for more than 10 years now. I don’t exactly remember when I bought it, but I’ve thrown it around quite hard and it still works great today.

That said, it’s not possible to have a forever-pump because all pumps have seals. These seals will slowly degrade over time. What you should look for is a company that sells spare parts and rebuild kits. Ideally a company that has been around for a long time so you can have a decent expectation that they’ll still be around when you need a rebuild kit (new-old-stock doesn’t work great for rubber/leather goods). Bonus points if the rebuild kit looks like parts that you could make or find from a local hardware store; just in case the company does fold.

Studies have shown that blinking lights improve reaction time to bikes on the road. The most common issue is determining the distance to the bike. This effect is more pronounced during night.

That’s why I use my bike lights all the time set to blink with a multi-second on phase. It makes me more noticeable and easy to estimate distance.

Also cars do have blinking lights these days. The newer car models like to blink the center brake light for a second before going static. Motorbikes have also long had rear blinking and “breathing” front light.

Interesting! Thanks for the explanation. :)

Has something changed recently? When I was in Tokyo, admittedly more than a decade ago now, the bike lanes were tiny slivers of paint. And I do mean a sliver; they were not much wider than a foot. It would be unsafe to use them in traffic.

Mozilla invented Rust to rewrite the rendering engine. Read the history of Servo and bring a tissue to cry into.

Specifically 5, 10, and 15mhz AM. There are others, but you’ll really hear NIST WWV/WWVH if you’re in North America/Pacific.

These disks were designed to self-destruct in the presence of oxygen. They literally rust away.

Oxygen and its O2 form does like to sneak into everything. Even sealed in the original packaging, there’s a limited shelf life. Flexplay claimed stability of only one year, which isn’t much given it comes sealed in a plastic bag.

You’re probably decoding noise or in the middle of the bit stream.

What you’re looking for is called “preamble.” That’s a sequence of bits used to synchronize the decoder (marks the start of data, useful in modulation schemes for clock recovery, and a few other things).

Looking at minimodem’s manual, try using the sync-byte option. Prepend your tar stream with a string of bytes, like 0x01, before sending to minimodem for encoding. Then use the sync code option to mark the start of the tar bit stream. This is as simple as cat preamble.bin myfiles.tar | minimodem --tx …

Other things to consider: start small with 300 baud BFSK before speeding up. Test with wav files before attempting physical tape or speakers and a microphone.

Oof. You definitely were taking a risk with that drive train. I’m glad the worst of it is a few broken spokes.

That’s clearly have a working bike, not some sort of weekend roadie show piece. Put a dork disk on there! There isn’t any shame in favoring function over form.

Awesome call-out on zip ties. They’re the duct tape of the bike world.

One small thing I noticed is how your fender and rack are mounted. It’s fine to share a single eyelet to mount both, but it’s best to mount in the order of frame, rack, fender, washer, and bolt. That ordering shortens the cantilever of the rack load, a much higher load than a fender, on the bolt.

For sure. These fuses have been a scourge.

Here’s a video by a radio fan who’s circuit is designed to blow fuses just didn’t.

https://youtu.be/apQU_VuJlFU