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Comment: Re:My B.S. Detector is Going Off (Score 2) 76

by Bruce Perens (#49515639) Attached to: Old Marconi Patent Inspires Tiny New Gigahertz Antenna

If the end of the coil that is hanging is grounded (earthed), it becomes an autotransformer. As it's shown, it's a variable inductor and the disconnected end is irrelevant and has no meaningful physical effect at the frequency a spark transmitter could have reached.

This comment seems to get closer to what they actually mean in their scientific paper. But the article about it is garble and the paper might suffer from second-language issues, and a lack of familiarity with the terms used in RF engineering.

Comment: Re:Hmm, I guess I invented this as well... (Score 1) 76

by Bruce Perens (#49513567) Attached to: Old Marconi Patent Inspires Tiny New Gigahertz Antenna

Damn, I wish I would have patented that and all its quantum magic...

I noticed that my vertical transmitting antenna often works better if I connect a horizontal wire about the same length as the antenna to ground at its base! The wire isn't connected to the transmitting side of the circuit at all! And how well it works varies depending on the length! Obviously there is some deus ex machina at work here...

Comment: Re:My B.S. Detector is Going Off (Score 1) 76

by Bruce Perens (#49513517) Attached to: Old Marconi Patent Inspires Tiny New Gigahertz Antenna

Clearly you missed the bit where they invoked quantum mechanics, surely that explains away all the inaccuracies, like the fact you can already buy chip scale dielectric antennas

The thing that I really hate about Innovation Stories is that the reporter invariably doesn't understand what's going on, and invariably is easily convinced that The Obviiously Very Technical People have some very valuable invention.

Comment: Re:vs. a Falcon 9 (Score 1) 75

by Bruce Perens (#49501071) Attached to: Rocket Lab Unveils "Electric" Rocket Engine

They can carry about 110kg to LEO, compared to the Falcon 9's 13150kg. That's 0.84% of the payload capacity. A launch is estimated to cost $4 900 000, compared to the Falcon 9's $61 200 000. That's 8.01%. That means cost per mass to orbit is nearly an order of magnitude worse.

Yes, this is a really small rocket. If you are a government or some other entity that needs to put something small in orbit right away, the USD$5 Million price might not deter you, even though you could potentially launch a lot of small satellites on a Falcon 9 for less.

And it's a missile affordable by most small countries, if your payload can handle the re-entry on its own. Uh-oh. :-)

Comment: Re:You Can See (Score 1) 113

Microminiature accelerometers are really cheap and very very light, and you don't have to wait for them to spin up or deal with their mechanical issues. I doubt you will see a gyro used as a sensor any longer.

Similarly, computers make good active stabilization possible and steering your engine to stabilize is a lot lighter than having to add a big rotating mass.

Comment: Re:Holy Stiction, Batman! WTF is hysteresis? (Score 1) 113

by MachDelta (#49490407) Attached to: An Engineering Analysis of the Falcon 9 First Stage Landing Failure

It's ok, I have a car analogy for hysteresis:

So, my first car was a 92 Plymouth Laser RS Turbo. It had a (rudimentary) cruise control system that wasn't quite capable enough for a turbocharged engine. The problem was that cruise control behaved as if throttle input was linear, but a 90's era turbocharged car is the very definition of non-linear throttle input. Thus, any time cruise was on and you hit a decent slope, the system would begin to oscillate. When the car slowed from climbing a hill, cruise control would apply more throttle - but then the turbo would spool up and you'd overshoot your desired speed. This caused the system to sharply back off, causing the turbo to slow, power to drop, and thus speed to drop too rapidly. The car ended up stuck in this long loop of "too slow, too slow, more gas more gas more more mooooOOOOH CRAP TOO MUCH TOO MUCH OFF OFF OFF WAY Ooooh that's better, much better this is nice, I'm right on, wait, no no no wait too slow, too slow more gas more more MOOOOAAAAHHHH TOO FAST TOO FAST..." which could sometimes last for miles, unchecked. That's a car experiencing hysteresis. The solution was as simple as very brief and very gentle throttle input right as the system started to back off too much. You could keep the turbo spooled and nail target speed for just a second, and then cruise could simply hold the throttle for you... until the next hill. Fortunately for me, I was young at the time and not quite as interested in cruise control as I was in long 3rd gear pulls while passing people on a two-lane highway.

An egghead is one who stands firmly on both feet, in mid-air, on both sides of an issue. -- Homer Ferguson

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