short waves


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short waves,

radio waves whose frequencies range from about 3 to 25 megahertz (Mhz), corresponding roughly to the high-frequency band (see radio frequencyradio frequency,
range of electromagnetic waves with a frequency or wavelength suitable for communication uses. Some of these waves serve as carriers of the lower-frequency audio waves; others are modulated by video or digital information.
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). When they impinge on certain layers of the ionosphere, short waves are largely reflected back toward the earth. By one or more reflections between the earth and the ionosphere, a short-wave radio signal can be received at long distances from the transmitter.
References in periodicals archive ?
Upstream short waves appear as the amplitude of the solitary wave becomes high with time.
The counterpart of short waves observed at Bo = 0.18 appears even at large Bond numbers (Bo [??] 0.30), with larger wavelength and amplitude as the Bond number increases.
6f), the original short waves become long nonlinear waves with larger wavelengths.
We now examine the behaviour of short waves upstream of the solitary wave.
We can directly measure the wavelength of upstream short waves [lambda] using the data at t = 400.
This means that the upstream short waves are almost linear waves, although their amplitude becomes larger for larger Bo, and nonlinear effects should become more significant.
These results show that the upstream short waves are linear waves whose phase speeds are equal to the upstream solitary waves.
The resulting Cold War set off a short wave of forcible regime promotion as the Soviet Union and the US competed internationally for spheres of influence in order to strengthen their external security.
[7.] Weinmann F., Dostert K., Verification of background noise in the short wave frequency range according to recommendation ITU-R P.372 // AEU--International Journal of Electronics and Communications, Volume 60, Issue 3, 1 March 2006.--P.
March 31, 2011 (NAIROBI) -- A Sudanese anti-government youth group announced on Thursday that it has launched a radio on short wave frequencies across the country in order to drum up support for regime change, a bold bid to challenge state control over broadcast media outlets in the country.
Altoraifi indicated that the channel that broadcasts 24 hours round the clock is working to cover Hajj rituals and live broadcast of all prayers from the Grand Holy Mosque, noting that it broadcasts via four satellites including Arabsat, Nilesat, Hotbird and Yah Sat" alongside radio broadcast on "FM and short waves on which Saudi radio stations broadcast to the world, as well as via mobile phone applications, and on radio and television commissions sites on the internet.
One youth opposition group known as Youth for Change, the shorthand of which is Shararah [Arabic for spark] has taken the battle to a whole new level by announcing the launch of its radio programming on short waves across the country.