Space roses, Cosmic Reindeer, Arctic space pendants, and more! ASTEROID FLYBY: Approaching from the direction of the sun, mountain-sized asteroid 2015 JO25 will fly past Earth on April 19th approximately 1.8 million km away. NASA says there is no danger of a collision. This unusually bright space rock is about twice as reflective as the Moon.
Broadcast Antennas. Radio and television broadcast stations transmit their signals via RF electromagnetic waves. Broadcast stations transmit at various RF frequencies, depending on the channel, ranging from about 550 kHz for AM radio up to about 800 MHz for some UHF television stations.
A radio transmitter is an electronic device which, when connected to an antenna, produces an electromagnetic signal such as in radio and television broadcasting, two way communications or radar.or better frequency stability, it was common to multiply the frequency of the oscillator up to the final, required frequency. This was accommodated by allocating the short wave amateur and marine bands in harmonically related frequencies such as 3.5, 7, 14 and 28 MHz.