A nice report about radio station from the NPR website

Dear readers ;

Here is a nice article regarding mysterious radio stations all over the world ( from here and here)

In the shadowy corners of the shortwave radio spectrum, you can often find mysterious mechanical voices counting off endless strings of numbers — in English, Czech, Russian and German … even Morse code. But who's listening?

The voices are coming from what are known as "numbers stations," and they've long been thought to be part of international espionage operations. In fact, the Russian spies recently captured here in the U.S. may have been getting orders from Moscow via a shortwave numbers station.

These broadcasts have been heard for at least 40 years. The signals are powerful, but they contain no information about location of the transmitter or the intended audience. Most listeners linger for a short time, then tune away, utterly baffled.

Starting in the mid-70's the "Numbers Stations" began to pique the curiosity of a small group of listeners. Numbers enthusiasts began using new receivers with digital readouts to better track these stations. Some, like Simon Mason and Hugh Stegman, spent hours hunting for and recording these stations. They compiled schedules through reverse engineering.

Another point of view come from Dxing.com :

Even though they do not operate on any fixed schedule or frequencies known to the public, numbers stations are really very easy to hear. Just tune outside the established shortwave broadcasting or ham radio bands and you'll hear several with patient tuning. While numbers stations can be heard any time on any frequencies, most seem to be heard in North America during the evening and night hours on frequencies from 3 to 12 MHz.

Most numbers stations heard in North America transmit in Spanish. Other languages often heard include English, German, and scattered other languages such as Chinese and Russian. Almost all will use a woman's voice, although on rare occasions a man's voice might be used. You will quickly notice that the numbers you hear sound much like the "intercept" messages used by telephone companies to give out new numbers when you dial a discontinued number, and a similar technology is obviously in use to generate numbers messages.

Five-digit Spanish stations are the most frequently heard variety. They begin transmissions with something like "atención 341 67" repeated for several minutes. The three-digit group is believed to the identifier of the recipient of the message, while the second number is the number of five-digit groups in the message. Sometimes as many as three different messages may be sent in the same transmission. Transmissions usually conclude with the words "fínal, fínal." Almost all of these stations use AM.

What is your opinion ?