Sunday, February 27, 2011 6:00 DXers Area Radio Society 
Area DXers 02/27/1911 DX programs usually dealing with VHF / FM, short, medium and long. The frequency lower in the scales of common receptors, 150 kHz, is the beginning of long waves.
already in 1900 with headphones was recorded a strange phenomenon: you hear a hissing sound similar to that accompanying the fall of a projectile, or a sound you hear when a tire burst. This phenomenon was investigated by scientists only in 1953. It was established that the sound in question appears at frequencies below 150 kHz, especially between 1 and 12 kHz.
Upon a lightning storm, strong electromagnetic signals are emitted. Some of them passing through the ionosphere and propagate along the lines of magnetic field strength of the Earth. Another part is reflected repeatedly on the surface of the Earth and the ionosphere. This mixed-signal reaches the listener and is manifested as noise and sounds just described. Even on a sunny day in Europe this noise and sounds can be heard coming from the distant tropics.
peculiar thing here is that this phenomenon can be observed by listeners located at latitudes between 25 and 65 degrees as the strongest signals are received in areas around latitude 50 degrees north or south.
signals of this kind should not be confused with the frequent crackles due to the effect of a nearby storm with thunder. These crackles can be heard mostly in the range 1 to 20 kilohertz.
always in the lower frequencies can also listen to the stations and frequency standard time signals. These transmitters broadcast on shortwave, but also in ultra long, in the range of 25 to 77.5 kHz. Most of these stations broadcast a signal that is heard as a peep or a beep, and each minute is announced by a human voice, most often in English.
On hearing this, the listener can see if your receiver is calibrated accurately, that is, if you specify exactly how often announced. Moreover, the arranged time is the most accurate in nature since it is based on the continuous correction between atomic time and astronomical time.
nine countries are used for this purpose in these wave frequencies in Russia, Belarus and Kyrgyzstan are together in 25, 50 and 66.66 kHz. Japan, Britain and the U.S. are in 60 kHz) while Japan is also at 40 kHz). China is at 68.5 kHz, 77.5 kHz in Germany and Switzerland in the 75 kHz.
Each station has a three-letter designation is announced during the program with voice or Morse signals from time to time, such as every hour.
signals also could be compared with emissions from stations short wavelengths, but only the U.S. and Russia simultaneously broadcast on shortwave and ultra-long waves.
Fans of this type of unusual radio signals require special equipment to receive these low frequencies, such as a frequency transformer or converter. Almost all receivers with long waves could be adapted and adjusted by a specialist to receive frequencies below 150 kHz. It
the receiver is also equipped with external antenna made from a common cable. Despite being of natural origin, these signals are mostly strong. The antenna is needed rather for the receipt of standard frequency stations and time signals.
English version of Raina Petkova
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