Mystery Signals of the Short Wave

Dedicated to the more unusual, strange, bizarre and apparently meaningless signals on the short wave bands !

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Russian Woodpecker | Yosemite Sam |

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The Grasshopper

Frequency:   (Various)   (Variable in 1,2,3 & 4 kHz steps)

Common Frequencies Used
        Around   10444 kHz   to   10514 kHz
        Around   9428 kHz          
        Around   11000 kHz   to   11100 kHz
        Around   12411 kHz

This signal consists of  a sound similar to that made by a grasshopper or cricket, and has a slower harsher sound than that of the Faders.  The signal appears to have some sort of "phase" effect, like that found on old 1960-70's pop records.

The signal will transmit on one frequency, then suddenly appear to drop in volume.  Retuning of the receiver however reveals that the signal has jumped up or down the band.  The move will be exactly 1, 2, 3, or 4 kHz from the original signal.

The sequence is then repeated, with the signal jumping to either another new sequence, or returning to its original frequency.

  "The Grasshopper"  (39 kb)

The sound of the signal, which is pulsed, does have some resemblance to the old Russian "Woodpecker" signal which caused so much controversy in the 1970's with it's powerful broad-band transmissions across the whole of the short-wave spectrum.

In Europe, try evenings from 1900 UTC.


In October 2000 I received an email from Paul Beaumont in England, who I had been in correspondence with on various radio topics. At the end of the email Paul had added;

"Incidentally the 'Grasshopper' sound that you refer to on your website is almost certainly a sample of the Super Dual Auroral Radar Network system recently heard."

A quick search on the internet found the SuperDARN website and an email to Rob Barnes, the project's Software Engineer, rapidly brought the following confirmation:

"The answer is yes - It does sound like the SuperDARN radars. The Radars run with a 7 second sampling period that consists of two parts:

1. A clear frequency search, where the Radar scans through a 300 KHz range looking for a low noise frequency.

2. The main integration loop where we transmit a 70-80ms pulse sequence as many times as possible in the remaining time."

Rob suggested looking at the Real-Time Data displays on the website, which allow tracking of the actual frequencies in use.

This gave the conclusive proof I was looking for - the source of "The Grasshopper" signal had been found.

For more information visit the SuperDARN Website.

Additional information can be found at   The University of Leicester Radio and Space Physics Group   web site. They operate two of the SuperDARN Radars in Finland and Iceland and have a lot more information about how the Radars work./

Be sure to look at Rob Barnes'   Real-Time Data Displays.

(Try "Hankasalmi B". When the Applet has loaded Click " Open Connection", Click "Fan Plot"). They are both fascinating and beautiful to observe and will also give you a real-time indication of the frequencies in use.

My sincere thanks to Rob Barnes for his help, and for allowing me to use his information on this page.

Finally, I am most grateful to Paul Beaumont whose sharp detective work solved the source of this mystery signal. Thanks Paul!

Update July 2004