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Genevieve Naylor/CORBIS

Why Do Radio Stations Begin With 'K' and 'W'?

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Genevieve Naylor/CORBIS

Radio might not be quite the media force it once was, but there are still hundreds of stations around the country, and each of them almost always begin their call letters with "K" or "W."

Why? Because the government said so.

In the days of the telegraph, operators started the practice of using short letter sequences as identifiers, referring to them as call letters or call signs. Early radio operators continued the practice, but without a central authority assigning call letters, radio operators often chose letters already in use, leading to confusion.

To alleviate the problem, the Bureau of Navigation (part of the Department of Commerce), began assigning three-letter call signs to American ships in the early 1910s.

Ships in the Atlantic and Gulf of Mexico got a K prefix and in the Pacific and the Great Lakes got a W. The precise reasons for choosing these two letters, if there were any, are unknown: Bureaucracy works in mysterious ways. At the 1912 London International Radiotelegraphic Convention, ranges of letters were assigned to each of the participating nations and the U.S. was told to keep using the W and most of the K range. (Military stations used N and A.)

When the federal government began licensing commercial radio stations later that year, it had planned to assign call letters to the land-based stations in the same way. Somehow, things got flipped during implementation, though, and Eastern stations got W call signs and the Western ones got Ks. Where exactly does the Bureau of Navigation draw the line between East and West? For a while it ran north from the Texas-New Mexico border, but shifted in 1923 to follow the Mississippi River.

Some areas, however, might have both a K and W station in the same vicinity. Why? When the dividing line switched, some stations were made to change their call signs, while others weren't. For about a year in the 1920s, the Bureau of Navigation that decided that all new stations were going to get a K call sign no matter where they were located. Still other exceptions were made by special request, station relocations, ownership changes, and even human error.

As for the rest of the call sign: That usually includes the station (ABC, NBC), but can also be an acronym. WGN stands for "World's Greatest Newspaper," while WTTW is "Windows to the World." But nothing beats St. Louis sports station KRAP, which gave themselves the very self-aware label in 2014. "Our staff is KRAP," reads their website. "Our signal is KRAP. Our studios are KRAP."


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Big Questions
How Does Autopilot Work on an Airplane?
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How does autopilot work on an airplane?

Joe Shelton:

David Micklewhyte’s answer is a good one. There are essentially a few types of features that different autopilots have. Some autopilots only have some of these features, while the more powerful autopilots do it all.

  • Heading Hold: There’s a small indicator that the pilot can set on the desired heading and the airplane will fly that heading. This feature doesn’t take the need for wind correction to desired routing into account; that’s left to the pilot.
  • Heading and Navigation: In addition to holding a heading, this version will take an electronic navigation input (e.g. GPS or VOR) and will follow (fly) that navigation reference. It’s sort of like an automated car in that it follows the navigator’s input and the pilot monitors.
  • Altitude Hold: Again, in addition to the above, a desired altitude can be set and the aircraft will fly at that altitude. Some autopilots have the capability for the pilot to select a desired altitude and a climb or descent rate and the aircraft will automatically climb or descend to that altitude and then hold the altitude.
  • Instrument Approaches: Autopilots with this capability will fly preprogrammed instrument approaches to the point where the pilot either takes control and lands or has the autopilot execute a missed approach.

The autopilot is a powerful computer that takes input from either the pilot or a navigation device and essentially does what it is told to do. GPS navigators, for example, can have a full flight plan entered from departure to destination, and the autopilot will follow the navigator’s guidance.

These are the majority of the controls on the autopilot installed in my airplane:

HDG Knob = Heading knob (Used to set the desired heading)

AP = Autopilot (Pressing this turns the autopilot on)

FD = Flight Director (A form of navigational display that the pilot uses)

HDG = Heading (Tells the autopilot to fly the heading set by the Heading Knob)

NAV = Tells the autopilot to follow the input from the selected navigator

APR = Tells the autopilot to fly the chosen approach

ALT = Tells the autopilot to manage the altitude, controlled by the following:

VS = Vertical Speed (Tells the autopilot to climb or descend at the chosen rate)

Nose UP / Nose DN = Sets the climb/descent rate in feet per minute

FLC = Flight Level Change (An easy manual way to set the autopilot)

ALT Knob = Used to enter the desired altitude

This post originally appeared on Quora. Click here to view.

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Big Questions
What's the Difference Between Vanilla and French Vanilla Ice Cream?
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While you’re browsing the ice cream aisle, you may find yourself wondering, “What’s so French about French vanilla?” The name may sound a little fancier than just plain ol’ “vanilla,” but it has nothing to do with the origin of the vanilla itself. (Vanilla is a tropical plant that grows near the equator.)

The difference comes down to eggs, as The Kitchn explains. You may have already noticed that French vanilla ice cream tends to have a slightly yellow coloring, while plain vanilla ice cream is more white. That’s because the base of French vanilla ice cream has egg yolks added to it.

The eggs give French vanilla ice cream both a smoother consistency and that subtle yellow color. The taste is a little richer and a little more complex than a regular vanilla, which is made with just milk and cream and is sometimes called “Philadelphia-style vanilla” ice cream.

In an interview with NPR’s All Things Considered in 2010—when Baskin-Robbins decided to eliminate French Vanilla from its ice cream lineup—ice cream industry consultant Bruce Tharp noted that French vanilla ice cream may date back to at least colonial times, when Thomas Jefferson and George Washington both used ice cream recipes that included egg yolks.

Jefferson likely acquired his taste for ice cream during the time he spent in France, and served it to his White House guests several times. His family’s ice cream recipe—which calls for six egg yolks per quart of cream—seems to have originated with his French butler.

But everyone already knew to trust the French with their dairy products, right?

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