Very high frequency
High frequency is the ITU designation for the range of radio frequency electromagnetic waves from 30 to 300 megahertz, with corresponding wavelengths of ten meters to one meter. Frequencies below VHF are denoted high frequency, the next higher frequencies are known as ultra high frequency. Common uses for radio waves in the VHF band are FM radio broadcasting, television broadcasting, two way land mobile radio systems, long range data communication up to several tens of kilometers with radio modems, amateur radio, marine communications. Air traffic control communications and air navigation systems work at distances of 100 kilometres or more to aircraft at cruising altitude. In the Americas and many other parts of the world, VHF Band I was used for the transmission of analog television; as part of the worldwide transition to digital terrestrial television most countries require broadcasters to air television in the VHF range using digital rather than analog format. Radio waves in the VHF band propagate by line-of-sight and ground-bounce paths.
They do not follow the contour of the Earth as ground waves and so are blocked by hills and mountains, although because they are weakly refracted by the atmosphere they can travel somewhat beyond the visual horizon out to about 160 km. They can penetrate building walls and be received indoors, although in urban areas reflections from buildings cause multipath propagation, which can interfere with television reception. Atmospheric radio noise and interference from electrical equipment is less of a problem in the band than at lower frequencies; the VHF band is the first band at which efficient transmitting antennas are small enough that they can be mounted on vehicles and portable devices, so the band is used for two-way land mobile radio systems, such as walkie-talkies, two way radio communication with aircraft and ships. When conditions are right, VHF waves can travel long distances by tropospheric ducting due to refraction by temperature gradients in the atmosphere. For analog TV, VHF transmission range is a function of transmitter power, receiver sensitivity, distance to the horizon, since VHF signals propagate under normal conditions as a near line-of-sight phenomenon.
The distance to the radio horizon is extended over the geometric line of sight to the horizon, as radio waves are weakly bent back toward the Earth by the atmosphere. An approximation to calculate the line-of-sight horizon distance is: distance in nautical miles = 1.23 × A f where A f is the height of the antenna in feet distance in kilometers = 12.746 × A m where A m is the height of the antenna in meters. These approximations are only valid for antennas at heights that are small compared to the radius of the Earth, they may not be accurate in mountainous areas, since the landscape may not be transparent enough for radio waves. In engineered communications systems, more complex calculations are required to assess the probable coverage area of a proposed transmitter station; the accuracy of these calculations for digital TV signals is being debated. VHF is the first band at which wavelengths are small enough that efficient transmitting antennas are short enough to mount on vehicles and handheld devices, a quarter wave whip antenna at VHF frequencies is 25 cm to 2.5 meter long.
So the VHF and UHF wavelengths are used for two-way radios in vehicles and handheld transceivers and walkie-talkies. Portable radios use whips or rubber ducky antennas, while base stations use larger fiberglass whips or collinear arrays of vertical dipoles. For directional antennas, the Yagi antenna is the most used as a high gain or "beam" antenna. For television reception, the Yagi is used, as well as the log-periodic antenna due to its wider bandwidth. Helical and turnstile antennas are used for satellite communication since they employ circular polarization. For higher gain, multiple Yagis or helicals can be mounted together to make array antennas. Vertical collinear arrays of dipoles can be used to make high gain omnidirectional antennas, in which more of the antenna's power is radiated in horizontal directions. Television and FM broadcasting stations use collinear arrays of specialized dipole antennas such as batwing antennas. Certain subparts of the VHF band have the same use around the world.
Some national uses are detailed below. 50–54 MHz: Amateur Radio 6-meter band. 108–118 MHz: Air navigation beacons VOR and Instrument Landing System localizer. 118–137 MHz: Airband for air traffic control, AM, 121.5 MHz is emergency frequency 144–148 MHz: Amateur Radio 2-meter band. The VHF TV band in Australia was allocated channels 1 to 10-with channels 2, 7 and 9 assigned for the initial services in Sydney and Melbourne, the same channels were assigned in Brisbane and Perth. Other capital cities and regional areas used a combination of these and other frequencies as available; the initial commercial services in Hobart and Darwin were allocated channels 6 and 8 rather than 7 or 9. By the early 1960s it became apparent that the 10 VHF channels were insufficient to support the growth of television services; this was rectified by the addition of th
The Box (U.S. TV channel)
The Box named the Video Jukebox Network, was an American broadcast and satellite television network that operated from 1985 to 2001. The network focused on music videos, which through a change in format in the early 1990s, were selected by viewer request via telephone; the network was distributed on cable and satellite providers, with additional carriage on over-the-air UHF television stations. The network launched as the Video Jukebox Network in 1985, it was a product of the Miami Music scene, was hosted by a group of local Miami Bass rappers known as Miami Boyz. Peters formed a record company called Peter's Records from the revenue earned by the Video Jukebox Network. Despite having his foot in the local Miami Bass scene, employing hip-hop producers from abroad, none of its artists managed to produce a hit record. Beginning in the early 1990s, the service – which adopted the shortened name The Box – began allowing viewers to request videos through a designated telephone number. At first, all of The Box's request lines used a large block of Miami telephone numbers and callers were only charged for a long distance call.
The network was well known for being an "underground" outlet for music videos that were not shown or banned on MTV, with up to 350 videos selectable at any given time in each of the 170 different Box affiliates throughout the United States. Each affiliate had a unique playlist customized to the local market, giving great exposure to more local and obscure groups. Videos cost between 99¢ and $3.99 and, on a national average, took around 20 minutes to be broadcast after being ordered. Because the channel's playlist was controlled by viewers, anyone could request any video for as many times as they wanted; the network was known for its rough-around-the-edges and "bootleg"-like feel, sometimes making it appear like it was of low quality. Despite this, The Box was known to have many popular videos appear in heavy rotation on The Box months before appearing on MTV – Britney Spears' "... Baby One More Time" was seen on The Box many months before "breaking out" for example – and was responsible in raising the profile of acts such as Sir Mix-A-Lot and Green Jellÿ.
In May 1999, The Box was acquired by MTV Networks division of Viacom. The Box ceased operations just over 1½ years on January 1, 2001; the concept behind The Box was revived in 2010, when cable music service Music Choice launched SWRV. Headends incorporated a video server which allowed for localized content mixes – local demographics could be taken into account for selecting the list of videos available for request or requested genres/bands could be queued automatically; the video server had up to a 64GB HDD and the video programs were compressed in the MPEG2 format. In 2000, The Box had 1,800 music videos in its inventory, 150 to 300 of which were queued across the network, at any given time. Subscribers could call the Interactive Voice Response at The Box's central office to request videos over the phone, typical, but could request over the internet or via set-top box; the central office would send the data to the individual headends regarding what was ordered. MTV2 The Box
Terrestrial television is a type of television broadcasting in which the television signal is transmitted by radio waves from the terrestrial transmitter of a television station to a TV receiver having an antenna. The term terrestrial is more common in Europe and Latin America, while in the United States it is called broadcast or over-the-air television; the term "terrestrial" is used to distinguish this type from the newer technologies of satellite television, in which the television signal is transmitted to the receiver from an overhead satellite, cable television, in which the signal is carried to the receiver through a cable. Terrestrial television was the first technology used for television broadcasting, with the first public television broadcast from Schenectady, NY, in January, 1928; the BBC began broadcasting in 1929 and by 1930 many radio stations had a regular schedule of experimental television programmes. However, these early experimental systems had insufficient picture quality to attract the public, due to their mechanical scan technology, television did not become widespread until after World War II with the advent of electronic scan television technology.
The television broadcasting business followed the model of radio networks, with local television stations in cities and towns affiliated with television networks, either commercial or government-controlled, which provided content. Television broadcasts were in black and white until the transition to color television in the 1950s and 60s. There was no other method of television delivery until the 1950s with the beginnings of cable television and community antenna television. CATV was only a re-broadcast of over-the-air signals. With the widespread adoption of cable across the United States in the 1970s and 1980s, viewing of terrestrial television broadcasts has been in decline. A slight increase in use began after the 2009 final conversion to digital terrestrial television broadcasts, which offer HDTV image quality as an alternative to CATV for cord cutters. Following the ST61 conference, UHF frequencies were first used in the UK in 1964 with the introduction of BBC2. In UK, VHF channels were kept on the old 405-line system, while UHF was used for 625-line broadcasts.
Television broadcasting in the 405-line system continued after the introduction of four analogue programmes in the UHF bands until the last 405-line transmitters were switched off on January 6, 1985. VHF Band III was used in other countries around Europe for PAL broadcasts until planned phase out and switchover to digital television; the success of analogue terrestrial television across Europe varied from country to country. Although each country had rights to a certain number of frequencies by virtue of the ST61 plan, not all of them were brought into service. In 1941, the first NTSC standard was introduced by the National Television System Committee; this standard defined a transmission scheme for a black and white picture with 525 lines of vertical resolution at 60 fields per second. In the earl of the first tragic 1950s, this standard was superseded by a backwards-compatible standard for color television; the NTSC standard was being used in the Americas as well as Japan until the introduction of digital terrestrial television.
While Mexico have ended all its analogue television broadcasts and the US and Canada have shut down nearly all of their analogue TV stations, the NTSC standard continues to be used in the rest of Latin American countries while testing their DTT platform. In the late 1990s and early 2000s, the Advanced Television Systems Committee developed the ATSC standard for digital high definition terrestrial transmission; this standard was adopted by many American countries, including the United States, Dominican Republic, Mexico, El Salvador and Honduras. The Pan-American terrestrial television operates on analog channels 2 through 6, 7 through 13, 14 through 51. Unlike with analog transmission, ATSC channel numbers do not correspond to radio frequencies. Instead, a virtual channel is defined as part of the ATSC stream metadata so that a station can transmit on any frequency but still show the same channel number. Additionally, free-to-air television repeaters and signal boosters can be used to rebroadcast a terrestrial television signal using an otherwise unused channel to cover areas with marginal reception.
Analog television channels 2 through 6, 7 through 13, 14 through 51 are only used for LPTV translator stations in the U. S. Channels 52 through 69 are still used by some existing stations, but these channels must be vacated if telecommunications companies notify the stations to vacate that signal spectrum. By convention, broadcast television signals are transmitted with horizontal polarization. Terrestrial television broadcast in Asia started as early as 1939 in Japan through a series of experiments done by NHK Broadcasting Institute of Technology. However, these experiments were interrupted by the beginning of the World War II in the Pacific. On February 1, 1953, NHK began broadcasting. On August 28, 1953, Nippon TV, the first commercial television broadcaster in Asia was launched. Meanwhile, in the Philippines, Alto Broadcasting System, the
Digital terrestrial television
Digital terrestrial television is a technology for broadcast television in which land-based television stations broadcast television content by radio waves to televisions in consumers' residences in a digital format. DTTV is a major technological advance over the previous analog television, has replaced analog, in common use since the middle of the 20th century. Test broadcasts began in 1998 with the changeover to DTTV beginning in 2006 and is now complete in many countries; the advantages of digital terrestrial television are similar to those obtained by digitising platforms such as cable TV, telecommunications: more efficient use of limited radio spectrum bandwidth, provision of more television channels than analog, better quality images, lower operating costs for broadcasters. Different countries have adopted different digital broadcasting standards; the amount of data that can be transmitted is directly affected by channel capacity and the modulation method of the transmission. North America uses the ATSC standard with 8VSB modulation, which has similar characteristics to the vestigial sideband modulation used for analog television.
This provides more immunity to interference, but is not immune to multipath distortion and does not provide for single-frequency network operation. The modulation method in DVB-T is COFDM with either 16-state Quadrature Amplitude Modulation. In general, 64QAM is capable of transmitting a greater bit rate, but is more susceptible to interference. 16 and 64QAM constellations can be combined in a single multiplex, providing a controllable degradation for more important program streams. This is called hierarchical modulation. DVB-T are designed to work in single frequency networks. Developments in video compression have resulted in improvements on the original H.262 MPEG 2 codec, surpassed by H.264/MPEG-4 AVC and more H.265 HEVC. H.264 enables three high-definition television services to be coded into a 24 Mbit/s DVB-T European terrestrial transmission channel. DVB-T2 increases this channel capacity to 40 Mbit/s, allowing more services. DTTV is received either via a digital set-top box, TV gateway or more now an integrated tuner included with television sets, that decodes the signal received via a standard television antenna.
These devices now include digital video recorder functionality. However, due to frequency planning issues, an aerial capable of receiving a different channel group may be required if the DTTV multiplexes lie outside the reception capabilities of the installed aerial; this is quite common in the UK. Indoor aerials are more to be affected by these issues and need replacing. Main articles: List of digital television deployments by country, Digital television transition Afghanistan launched digital transmissions in Kabul using DVB-T2/MPEG-4 on Sunday, 31 August 2014. Test transmissions had commenced on 4 UHF channels at the start of June 2014. Transmitters were provided by GatesAir. Bangladesh had its first DTT service DVB-T2 / MPEG-4 on April 2016 launched by the GS Group; the service is called RealVU. It is done with partnership with Beximco. GS Group acts as a supplier and integrator of its in-house hardware and software solutions for the operator's functioning in accordance with the modern standards of digital television.
RealVu provides more than 100 TV channels in HD quality. The digital TV set-top boxes developed by GS Group offer such functions as PVR and time-shift, along with an EPG. India adopted DVB-T system for digital television in July 1999; the first DVB-T transmission was started on 26 January 2003 in the four major metropolitan cities by Doordarshan. The terrestrial transmission is available in both digital and analog formats. 4 high power DVB-T transmitters were set up in the top 4 cities, which were upgraded to DVB-T2 + MPEG4 and DVB-H standards. An additional 190 high power, 400 low power DVB-T2 transmitters have been approved for Tier I, II and III cities of the country by 2017; the Indian telecom regulator, TRAI, had recommended the I&B to allow private broadcast companies to use the DTT technology, in 2005. So far, the Indian I&B ministry only permits private broadcast companies to use satellite, cable and IPTV based systems; the government's broadcasting organisation Doordarshan had started the free TV service over DVB - T2 to the mobile phone users from February 25 onwards and extended to cover 16 cities including the four metros from April 5, 2016.
Israel started digital transmissions in MPEG-4 on Sunday, August 2, 2009, anal
Federal Communications Commission
The Federal Communications Commission is an independent agency of the United States government created by statute to regulate interstate communications by radio, wire and cable. The FCC serves the public in the areas of broadband access, fair competition, radio frequency use, media responsibility, public safety, homeland security; the FCC was formed by the Communications Act of 1934 to replace the radio regulation functions of the Federal Radio Commission. The FCC took over wire communication regulation from the Interstate Commerce Commission; the FCC's mandated jurisdiction covers the 50 states, the District of Columbia, the Territories of the United States. The FCC provides varied degrees of cooperation and leadership for similar communications bodies in other countries of North America; the FCC is funded by regulatory fees. It has an estimated fiscal-2016 budget of US $388 million, it has 1,688 federal employees, made up of 50% males and 50% females as of December, 2017. The FCC's mission, specified in Section One of the Communications Act of 1934 and amended by the Telecommunications Act of 1996 is to "make available so far as possible, to all the people of the United States, without discrimination on the basis of race, religion, national origin, or sex, efficient and world-wide wire and radio communication services with adequate facilities at reasonable charges."
The Act furthermore provides that the FCC was created "for the purpose of the national defense" and "for the purpose of promoting safety of life and property through the use of wire and radio communications."Consistent with the objectives of the Act as well as the 1999 Government Performance and Results Act, the FCC has identified four goals in its 2018-22 Strategic Plan. They are: Closing the Digital Divide, Promoting Innovation, Protecting Consumers & Public Safety, Reforming the FCC's Processes; the FCC is directed by five commissioners appointed by the President of the United States and confirmed by the United States Senate for five-year terms, except when filling an unexpired term. The U. S. President designates one of the commissioners to serve as chairman. Only three commissioners may be members of the same political party. None of them may have a financial interest in any FCC-related business. † Commissioners may continue serving until the appointment of their replacements. However, they may not serve beyond the end of the next session of Congress following term expiration.
In practice, this means that commissioners may serve up to 1 1/2 years beyond the official term expiration dates listed above if no replacement is appointed. This would end on the date that Congress adjourns its annual session no than noon on January 4; the FCC is organized into seven Bureaus, which process applications for licenses and other filings, analyze complaints, conduct investigations and implement regulations, participate in hearings. The Consumer & Governmental Affairs Bureau develops and implements the FCC's consumer policies, including disability access. CGB serves as the public face of the FCC through outreach and education, as well as through their Consumer Center, responsible for responding to consumer inquiries and complaints. CGB maintains collaborative partnerships with state and tribal governments in such areas as emergency preparedness and implementation of new technologies; the Enforcement Bureau is responsible for enforcement of provisions of the Communications Act 1934, FCC rules, FCC orders, terms and conditions of station authorizations.
Major areas of enforcement that are handled by the Enforcement Bureau are consumer protection, local competition, public safety, homeland security. The International Bureau develops international policies in telecommunications, such as coordination of frequency allocation and orbital assignments so as to minimize cases of international electromagnetic interference involving U. S. licensees. The International Bureau oversees FCC compliance with the international Radio Regulations and other international agreements; the Media Bureau develops and administers the policy and licensing programs relating to electronic media, including cable television, broadcast television, radio in the United States and its territories. The Media Bureau handles post-licensing matters regarding direct broadcast satellite service; the Wireless Telecommunications Bureau regulates domestic wireless telecommunications programs and policies, including licensing. The bureau implements competitive bidding for spectrum auctions and regulates wireless communications services including mobile phones, public safety, other commercial and private radio services.
The Wireline Competition Bureau develops policy concerning wire line telecommunications. The Wireline Competition Bureau's main objective is to promote growth and economical investments in wireline technology infrastructure, development and services; the Public Safety and Homeland Security Bureau was launched in 2006 with a focus on critical communications infrastructure. The FCC has eleven Staff Offices; the FCC's Offices provide support services to the Bureaus. The Office of Administrative Law Judges is responsible for conducting hearings ordered by the Commission; the hearing function includes acting on interlocutory requests filed in the proceedings such as petitions to intervene, petitions to enlarge issues, contested discovery requests. An Administrative Law Judge, appointed under the Administrative Procedure Act, presides at the hearing during which documents and sworn testimony are received in evidence, witnesses are cross-examined. At the co
Cable television is a system of delivering television programming to consumers via radio frequency signals transmitted through coaxial cables, or in more recent systems, light pulses through fiber-optic cables. This contrasts with broadcast television, in which the television signal is transmitted over the air by radio waves and received by a television antenna attached to the television. FM radio programming, high-speed Internet, telephone services, similar non-television services may be provided through these cables. Analog television was standard in the 20th century, but since the 2000s, cable systems have been upgraded to digital cable operation. A "cable channel" is a television network available via cable television; when available through satellite television, including direct broadcast satellite providers such as DirecTV, Dish Network and Sky, as well as via IPTV providers such as Verizon FIOS and AT&T U-verse is referred to as a "satellite channel". Alternative terms include "non-broadcast channel" or "programming service", the latter being used in legal contexts.
Examples of cable/satellite channels/cable networks available in many countries are HBO, Cinemax, MTV, Cartoon Network, AXN, E!, FX, Discovery Channel, Canal+, Fox Sports, Disney Channel, Nickelodeon, CNN International, ESPN. The abbreviation CATV is used for cable television, it stood for Community Access Television or Community Antenna Television, from cable television's origins in 1948. In areas where over-the-air TV reception was limited by distance from transmitters or mountainous terrain, large "community antennas" were constructed, cable was run from them to individual homes; the origins of cable broadcasting for radio are older as radio programming was distributed by cable in some European cities as far back as 1924. To receive cable television at a given location, cable distribution lines must be available on the local utility poles or underground utility lines. Coaxial cable brings the signal to the customer's building through a service drop, an overhead or underground cable. If the subscriber's building does not have a cable service drop, the cable company will install one.
The standard cable used in the U. S. is RG-6, which has a 75 ohm impedance, connects with a type F connector. The cable company's portion of the wiring ends at a distribution box on the building exterior, built-in cable wiring in the walls distributes the signal to jacks in different rooms to which televisions are connected. Multiple cables to different rooms are split off the incoming cable with a small device called a splitter. There are two standards for cable television. All cable companies in the United States have switched to or are in the course of switching to digital cable television since it was first introduced in the late 1990s. Most cable companies require a set-top box or a slot on one's TV set for conditional access module cards to view their cable channels on newer televisions with digital cable QAM tuners, because most digital cable channels are now encrypted, or "scrambled", to reduce cable service theft. A cable from the jack in the wall is attached to the input of the box, an output cable from the box is attached to the television the RF-IN or composite input on older TVs.
Since the set-top box only decodes the single channel, being watched, each television in the house requires a separate box. Some unencrypted channels traditional over-the-air broadcast networks, can be displayed without a receiver box; the cable company will provide set top boxes based on the level of service a customer purchases, from basic set top boxes with a standard definition picture connected through the standard coaxial connection on the TV, to high-definition wireless DVR receivers connected via HDMI or component. Older analog television sets are "cable ready" and can receive the old analog cable without a set-top box. To receive digital cable channels on an analog television set unencrypted ones, requires a different type of box, a digital television adapter supplied by the cable company. A new distribution method that takes advantage of the low cost high quality DVB distribution to residential areas, uses TV gateways to convert the DVB-C, DVB-C2 stream to IP for distribution of TV over IP network in the home.
In the most common system, multiple television channels are distributed to subscriber residences through a coaxial cable, which comes from a trunkline supported on utility poles originating at the cable company's local distribution facility, called the "headend". Many channels can be transmitted through one coaxial cable by a technique called frequency division multiplexing. At the headend, each television channel is translated to a different frequency. By giving each channel a different frequency "slot" on the cable, the separate television signals do not interfere with each other. At an outdoor cable box on the subscriber's residence the company's service drop cable is connected to cables distributing the signal to different rooms in the building. At each television, the subscriber's television or a set-top box provided by the cable company translates the desired channel back to its original frequency, it is displayed onscreen. Due to widespread cable theft in earlier analog systems, the signals are encrypted on m
The National Broadcasting Company is an American English-language commercial terrestrial television network, a flagship property of NBCUniversal, a subsidiary of Comcast. The network is headquartered at 30 Rockefeller Plaza in New York City, with additional major offices near Los Angeles and Philadelphia; the network is one of the Big Three television networks. NBC is sometimes referred to as the "Peacock Network", in reference to its stylized peacock logo, introduced in 1956 to promote the company's innovations in early color broadcasting, it became the network's official emblem in 1979. Founded in 1926 by the Radio Corporation of America, NBC is the oldest major broadcast network in the United States. At that time the parent company of RCA was General Electric. In 1930, GE was forced to sell the companies as a result of antitrust charges. In 1986, control of NBC passed back to General Electric through its $6.4 billion purchase of RCA. Following the acquisition by GE, Bob Wright served as chief executive officer of NBC, remaining in that position until his retirement in 2007, when he was succeeded by Jeff Zucker.
In 2003, French media company Vivendi merged its entertainment assets with GE, forming NBC Universal. Comcast purchased a controlling interest in the company in 2011, acquired General Electric's remaining stake in 2013. Following the Comcast merger, Zucker left NBCUniversal and was replaced as CEO by Comcast executive Steve Burke. NBC has thirteen owned-and-operated stations and nearly 200 affiliates throughout the United States and its territories, some of which are available in Canada and/or Mexico via pay-television providers or in border areas over-the-air. During a period of early broadcast business consolidation, radio manufacturer Radio Corporation of America acquired New York City radio station WEAF from American Telephone & Telegraph. Westinghouse, a shareholder in RCA, had a competing outlet in Newark, New Jersey pioneer station WJZ, which served as the flagship for a loosely structured network; this station was transferred from Westinghouse to RCA in 1923, moved to New York City. WEAF acted as a laboratory for AT&T's manufacturing and supply outlet Western Electric, whose products included transmitters and antennas.
The Bell System, AT&T's telephone utility, was developing technologies to transmit voice- and music-grade audio over short and long distances, using both wireless and wired methods. The 1922 creation of WEAF offered a research-and-development center for those activities. WEAF maintained a regular schedule of radio programs, including some of the first commercially sponsored programs, was an immediate success. In an early example of "chain" or "networking" broadcasting, the station linked with Outlet Company-owned WJAR in Providence, Rhode Island. C. WCAP. New parent RCA saw an advantage in sharing programming, after getting a license for radio station WRC in Washington, D. C. in 1923, attempted to transmit audio between cities via low-quality telegraph lines. AT&T refused outside companies access to its high-quality phone lines; the early effort fared poorly, since the uninsulated telegraph lines were susceptible to atmospheric and other electrical interference. In 1925, AT&T decided that WEAF and its embryonic network were incompatible with the company's primary goal of providing a telephone service.
AT&T offered to sell the station to RCA in a deal that included the right to lease AT&T's phone lines for network transmission. RCA spent $1 million to purchase WEAF and Washington sister station WCAP, shut down the latter station, merged its facilities with surviving station WRC; the division's ownership was split among RCA, its founding corporate parent General Electric and Westinghouse. NBC started broadcasting on November 15, 1926. WEAF and WJZ, the flagships of the two earlier networks, were operated side-by-side for about a year as part of the new NBC. On January 1, 1927, NBC formally divided their respective marketing strategies: the "Red Network" offered commercially sponsored entertainment and music programming. Various histories of NBC suggest the color designations for the two networks came from the color of the pushpins NBC engineers used to designate affiliate stations of WEAF and WJZ, or from the use of double-ended red and blue colored pencils. On April 5, 1927, NBC expanded to the West Coast with the launch of the NBC Orange Network known as the Pacific Coast Network.
This was followed by the debut of the NBC Gold Network known as the Pacific Gold Network, on October 18, 1931. The Orange Network carried Red Network programming, the Gold Network carried programming from the Blue Network; the Orange Network recreated Eastern Red Network programming for West Coast stations at KPO in San Francisco. In 1936, the Orange Network affiliate stations became part of the Red Network, at the same time the Gold Network became part of the Blue Network. In the 1930s, NBC developed a network for shortwave radio stations, called the NBC White Network. In 1927, NBC moved its operations to 711 Fifth Avenue in Manhattan, occupying the upper floors of a building de