Showing posts from 2012

Fun with RADAR

Say 'radar' and most people think of FAA air traffic controllers following airplanes or NASA engineers tracking rockets. But RAdio Detection And Ranging can be used for a lot of purposes including some that are simply fun. Especially when you can put a whole radar system on a 5mm x 5mm chip, like ViaSat managed to do.

If you stand in a canyon and yell, you'll hear an echo when the sound of your voice bounces off the side of the canyon and back to you. Like timing a thunder clap to judge distance to lightning, if you time the echo of your yell and know the speed of sound (roughly a 1000 feet per second) you can estimate how far away the cliffs are (and how close a thunderstorm is).

With radar you essentially do the same thing except you use a radio signal instead of sound, and the signal propagates at almost the speed of light (about 11 inches per nanosecond). Send a radio pulse, listen carefully for an echo, and you can tell how far away something is by measuring how long…

Satellite Solutions

Technology is always in the news these days, but there's one spectacular device out there you've probably never heard of.

ViaSat-1, launched in late 2011, provides more capacity in one satellite than all other communications satellites over North America combined. It will help 1,000,000 technologically deprived web surfers on the ground, in the air, and on the high seas join the 21st Century.

If you rummage around online forums about broadband services you'll find grumps who complain that satellite services can be interrupted by something as common as rain. That used to be true, but engineers have found a solution so the ViaSat Exede service will do just that— exceed your expectations. Now it's just silly to worry about weather effects except under the most extreme circumstances.

Jim Petranovich, MIT grad and Chief Geek at ViaSat subsidiary Enerdyne, wrote a technical  whitepaper that discusses the ways ViaSat reduces and prevents the affects of weather for users of th…

Robot Wars

Our robot took its first steps today. Now there's a line I never thought I'd write. I read more science fiction than most people, I suspect, but somehow I never really thought I'd own a robot. But I do.

Come to think of it, this baby is our second. Several years ago we bought an iRobot Roomba.

Rommba sucks, but that's a good thing for a vacuum cleaner. In fact, it works very well indeed, and while initially we thought it was kinda expensive, it definitely has earned its keep, wandering around nibbling odds and ends and scarfing down cat hair. When it gets caught under the sofa it bleats, "Oh-oh" a few times, and then patiently goes to sleep until we rescue it. Free to roam, it even heads home to find its docking station when the battery runs low and it needs to literally recharge its batteries.

But the second little bundle of joy came into out lives when my son, in a geneologically confusing sorta way, gave us a brother for Roomba—iRobot Create. We call him V…

Zero G Isn't Gravity free

Watch a Space Shuttle launch and you'll hear about "zero gravity" and "zero G", terms that make people think (incorrectly) that someone or something in orbit has somehow escaped Earth's gravity. Not so. Without gravity you couldn't put a spacecraft in orbit. Imagine hitting a baseball across a ballfield. Picture the arc it makes as it goes off into the outfield. To hit a home run, you have to hit it higher, and harder,  to make a bigger arc that takes it out over the fence.
Now imagine launching the ball using a catapult, a cannon, and finally a rocket. As you send it with more force, the ball arcs out higher and faster, and lands farther and farther away--across the street, out of the neighborhood, over your town, across your country, even across the nearest ocean.
Eventually, if you launch it high enough and hard enough it will sail right over the distant curving edge of the earth itself. Instead of coming down, it literally misses the surface, gravity p…