Radio Waves

• VHF stands for Very High Frequency. VHF radio waves are from 30 to 300 MHz. Radio waves are invisible electromagnetic waves, and they travel at the speed of light -- 186,282 miles per second.
  
  

Auxiliary Jacks

• Auxiliary jacks, noted as IN1, IN2 or OUT1 and OUT2, are for attaching coaxial cables. IN stands for input and the corresponding digit is the port's numerical designation.
  
  

Fun Facts

• The United States formed the Federal Radio Commission in 1927 to monitor radio frequencies and govern radio stations. In 1928, the British Broadcasting Company (BBC) began broadcasting programs that included news, music and theatrical plays. Guglielmo Marconi, an Italian physicist and inventor, is probably best known as the father of radio. In 1901, Marconi sent a signal via radio from England to Canada. The Morse code signal traveled more than 2,000 miles. It was the first time a radio signal had traveled such a distance.