Issue link: https://digital.copcomm.com/i/683118
15 TELEVISION HISTORY In the 1930s, television experiments were demonstrated and proponents were asking the FCC to allow them to be- gin transmitting pictures to the public. The Radio Manu- facturers Association (RMA) proposed a television stan- dard but not everyone accepted the standard. Finally, the FCC declared that until there is a nationwide standard, there would be no public television. The National Television System Committee (NTSC) was formed in July 1940 to create such a standard. Meetings were held and every part of television broadcasting was reviewed. In March 1941, an FCC hearing was held and a consensus standard presented by the NTSC. The FCC ad- opted those standards and allowed television broadcast- ing to start with what is known today as NTSC 525-line television. Different incompatible television channel plans had been proposed but in April 1941, eighteen television channels were assigned in low-band VHF (50 MHz–108 MHz) and high-band VHF (162 MHz–294 MHz). World War II stopped all television progress as all of the VHF and UHF bands were assigned to the military for "the war ef- fort" and consumer manufacturing was converted to military needs. After the war ended, the TV channel plan was changed again to make space for high-band VHF FM broadcast 88 MHz–108 MHz, leaving thirteen television channels in low- band and high-band VHF. The FCC was also pressured to make more frequencies available for land mobile communi- cations so television Channel 1 (44 MHz–50 MHz) was taken away from broadcasting and assigned to land mobile commu- nications. That's why with the exception of the very fi rst-gen- eration television sets, all US televisions start at Channel 2. The important picture is that there are no unused bands of frequencies shown on Figure 1. Any new use of RF has to take spectrum away from someone else. The rest of this article will describe how cellular telephones and wireless personal de- vices have been taking RF spectrum away from traditional RF uses. Very quickly, TV stations went on the air and the thirteen channels were fi lled in major cities. Around 1950, the mil- itary returned most of the UHF spectrum to civilian use and in 1952, UHF TV Channels 14 (470 MHz–476 MHz) through Channel 83 (884 MHz–890 MHz) were made available for television. Note that UHF TV Channel 37 is reserved through inter- national agreement for astronomical radio telescopes. No high-power transmitter is allowed on this channel to pro- tect those observations. UHF TV stations had a problem because TV receivers only received VHF TV Channels 2–13. To receive any of the UHF channels, one needed to purchase a special "set top" con- verter. This required user-profi ciency because the UHF tuner didn't have click stops and the user had to carefully tune in the UHF channel. Generally, TV antennas were VHF only and did not pick up UHF stations well. Another problem was that the UHF band had a lot more loss and fi rst-generation UHF television transmitters had relatively low power. Many new UHF stations went broke in a year or two and disappeared because viewers were unable to fi nd the sta- tions and without an audience, the station had no cash fl ow. Finally, Congress passed the All-Channel Receiver Act of 1962. It required all television set manufacturers to in- clude built-in UHF tuners in television receivers sold after 1964. Gradually, more television sets could receive UHF channels and with improvements in UHF transmitters for much higher power, UHF TV stations started to gain an audience and stay in business. FIGURE 2