STEM Blog
What the Heck is a Pulsed Hyperbolic System Anyway?
Finding our way to any destination is something we take for granted today with global positioning system (GPS) apps. But we didn’t always have GPS. What did we do before? In 1920, the first aircraft experimented with radio navigation. A US naval seaplane took off from Norfolk VA to see if it could find a…
Huff Duff Elephant Cages
Go to Google Earth and type in Elmendorf Air Force Base. To the northwest of the runways, near the water, you’ll see a round thing that looks like a big eye. What in the world is that? If a satellite can see it, it must be big. In fact, it covers about 40 acres, which…
Woodpeckers and Over the Horizon Radar
Christopher Columbus sailed west across the Atlantic Ocean hoping to find a new course to the East Indies. Because of the curvature of the earth, he could only see as far ahead as was visible before it curved out of sight. This magical disappearing point, known as the horizon, depends on how far above the…
Electronic Warfare and Cyberspace
The writer Stephen King once said, “Sooner or later, everything old is new again.” Today we’re going to talk about how old techniques – like jamming, spoofing, chaff, and flares – re-emerged as new techniques in cyberspace. Aren’t these apples and oranges? Don’t all these old electronic warfare technologies only use the electromagnetic spectrum (EMS)?…
Spoofing, Jamming, Chaff, and Flares
I promised this week I’d talk about spoofing, jamming, chaff, and flares. The military refers to these as countermeasures (CM). CM are devices or techniques used to cripple the effectiveness of enemy activities. They can include things that interfere with or mislead enemy communications, radars, and weapons systems. Let’s talk about some early examples. The telegraph was…
Identification, Friend or Foe (IFF)
Last week I told you that the creation of the E-Z pass had been inspired by a World War II technology known as Identification, Friend or Foe (IFF). Both IFF and the first operational radar system – the Chain Home (CH) system – were developed and used in Britain in anticipation of and during World…
The Amazing E-Z Pass
Today we’re going to talk about the E-Z pass. You’ve probably seen one of these card-deck-sized devices mounted on the inside of a windshield. The radio inside it allows a person’s account to be charged automatically for using a toll road. We’ve had toll roads in America since 1792, when the Philadelphia and Lancaster Turnpike…
You Say Radar, I Say Lidar
We’re going to return to land this week and talk about how police use the principles of radar to measure a vehicle’s speed. A policeman can use a radar gun to send an electromagnetic pulse at a specific frequency from his radar’s transmitting antenna towards a target vehicle. In the U.S., the most common radar…
The Bat, the Whale, and the Secretive ELF
The world’s smallest flying mammal, the bat, has its own tiny sonar system. It emits sounds at high frequencies (around 20 kHz to 100 kHz) to find its way in the dark, locate tasty insects, and avoid predators. Bats also make sounds to communicate with one another. We can think of this as bat speech!…
Sonar
In the film The Hunt for Red October, Soviet submarine captain Marko Ramius pulls a “crazy Ivan” maneuver, suddenly turning his vessel away from its established course. Ramius made the turn because a blind spot was preventing him from seeing anything that might have been following his Red October submarine. What do we mean by “see”…