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  2. Shortwave bands - Wikipedia

    en.wikipedia.org/wiki/Shortwave_bands

    Shortwave bands are frequency allocations for use within the shortwave radio spectrum (the upper medium frequency [MF] band and all of the high frequency [HF] band). Radio waves in these frequency ranges can be used for very long distance (transcontinental) communication because they can reflect off layers of charged particles in the ionosphere and return to Earth beyond the horizon, a ...

  3. Radio spectrum - Wikipedia

    en.wikipedia.org/wiki/Radio_spectrum

    Radar-frequency bands according to IEEE standard [17] Band designation Frequency range Explanation of meaning of letters; HF: 0.003 to 0.03 GHz: High frequency [18] VHF: 0.03 to 0.3 GHz: Very high frequency [18] UHF: 0.3 to 1 GHz: Ultra-high frequency [18] L: 1 to 2 GHz: Long wave S: 2 to 4 GHz: Short wave C: 4 to 8 GHz: Compromise between S ...

  4. Shortwave radio - Wikipedia

    en.wikipedia.org/wiki/Shortwave_radio

    Grundig Satellit 400 solid-state, digital shortwave receiver, c. 1986 [1]. Shortwave radio is radio transmission using radio frequencies in the shortwave bands (SW). There is no official definition of the band range, but it always includes all of the high frequency band (HF), which extends from 3 to 30 MHz (approximately 100 to 10 metres in wavelength).

  5. 15-meter band - Wikipedia

    en.wikipedia.org/wiki/15-meter_band

    The 15-meter band (also called the 21-MHz band or 15 meters) is an amateur radio frequency band spanning the shortwave spectrum from 21 to 21.45 MHz. The band is suitable for amateur long-distance communications , and such use is permitted in nearly all countries.

  6. Diathermy - Wikipedia

    en.wikipedia.org/wiki/Diathermy

    Diathermy is produced by two techniques: short-wave radio frequencies in the range 1–100 MHz (shortwave diathermy) or microwaves typically in the 915 MHz or 2.45 GHz bands (microwave diathermy), the methods differing mainly in their penetration capability. [4] [5] [6] It exerts physical effects and elicits a spectrum of physiological responses.

  7. List of shortwave radio broadcasters - Wikipedia

    en.wikipedia.org/wiki/List_of_shortwave_radio...

    Frequency (MHz) Program Transmitter site Time, UTC Days Language Power (kW) Az Remarks 3.965 Radio France Internationale (DRM) Issoudun 01:00-00:57 1234567 French (Digital) 1 ND RFI 3.975 6160 Shortwave AM Radio Winsen 16:00-18:00 .234567 English 1 ND 3.985 SRF Schweizer Radio Kall-Krekel 16:00-17:00 1234567 German 1 ND 3.995 HCJB Deutsch

  8. Electromagnetic spectrum - Wikipedia

    en.wikipedia.org/wiki/Electromagnetic_spectrum

    The spectrum is divided into separate bands, with different names for the electromagnetic waves within each band. From low to high frequency these are: radio waves, microwaves, infrared, visible light, ultraviolet, X-rays, and gamma rays. The electromagnetic waves in each of these bands have different characteristics, such as how they are ...

  9. 20-meter band - Wikipedia

    en.wikipedia.org/wiki/20-meter_band

    The 20-meter or 14-MHz amateur radio band is a portion of the shortwave radio spectrum, comprising frequencies stretching from 14.000 MHz to 14.350 MHz. [1] The 20-meter band is widely considered among the best for long-distance communication ( DXing ), and is one of the most popular—and crowded—during contests . [ 2 ]