Feb 23, 2021 20:00:00

What is the true identity of the mysterious and powerful signal found by amateur radio operators?

An amateur radio operator reported on his blog that he accidentally discovered an extremely large amount of communication, and made a surprising reasoning about what the communication was used for.

KA7OEI's blog: Intruder at the top of the 20 meter amateur band?

http://ka7oei.blogspot.com/2020/12/intruder-at-top-of-20-meter-amateur-band.html

KA7OEI, an amateur radio operator who works with the call sign of 'KA7OEI', discovered suspicious communication that he did not know while developing WebSDR , which is a wireless system that can use the Internet.

The communication is below. Mr. KA7OEI found out that a strong signal is emitted by radio waves in the 14MHz band called the 20m band.

Intrigued by this signal, KA7OEI tried a positioning method that used multiple receivers scattered throughout the continental United States to measure its source from the TDOA (arrival time difference) of radio waves. As a result, it was found that the signal originated from around Chicago. However, since this method only knows the approximate position, it is impossible to identify where and what facility the radio waves are coming from.

I don't know where the signal is coming from, but since communication by extremely strong radio waves is taking place in big cities, KA7OEI said that the identity of the above-mentioned communication is '

high frequency trading using shortwave (HFT). ) Isn't it? '

HFT is a trading method that uses the Internet and algorithms to place extremely fast and frequent stock trading orders. You can read more about HFT by reading the following articles.

How did the world's first 'high frequency trading' begin? --GIGAZINE

by Francisco Gonzalez

According to Mr. KA7OEI, the speed of light passing through an optical fiber is only one-third of the speed in free space . Therefore, the arrival of data in optical fiber communication is slightly delayed compared to radio wave communication. This difference is so small that humans can't feel it, but it can be decisive for HFTs that trade in less than a thousandth of a second.

Mr. KA7OEI thinks that it is the true nature of mysterious communication that he tried to use HFT with even a little advantage by using this 'difference in speed between wireless communication and optical line'. Although HFT itself is not illegal, it is against the law to use radio waves without permission, so Mr. KA7OEI called for information on suspicious communication and notification to the radio administrator.

Hacker News, an internet bulletin board system featuring Mr. KA7OEI's article, said, 'A financial institution conducting HFT has applied to the authorities to build a radio tower near Chicago, and has received permission (PDF file) . The information is written.