Radio Frequency Allocation and the Digital TV Transition:
A Historical Perspective
By: Dick Golembiewski
(Partially excerpted from a forthcoming book on Milwaukee TV history)
Updated: 21 August 2007
By 17 February 2009, all television in the United States must switch to using a digital signal. This is a radical change to the way television is broadcast, and will affect all viewers in some way. The reasons for the change are complex. The following will provide some historical perspective on why the transition has been mandated.
All over-the-air broadcasting uses a portion of the electro-magnetic spectrum called the "radio frequencies". Initially, those broadcasting by "wireless" utilized whatever frequency they had the technical capability to transmit on. At first, there was no government control over radio frequencies. With the outbreak of WWI, the federal government chose to take over control of domestic frequencies in the interest of national defense. After the war, many governments, such as that of Great Britain, chose to retain both control and ownership of the radio spectrum, and formed government-controlled broadcasting systems. In the U.S., the federal government chose to allow private interests to run broadcasting stations. Regulation was via the Radio Act of 1912, which placed control in the hands of the Department of Commerce. With technical improvements, broadcasting by radio began in earnest in the early 1920s.
Then Secretary of Commerce Herbert Hoover was frustrated in his attempts to regulate the radio industry by the federal courts. The result was "anarchy in the ether". Stations broadcast over whatever frequency the desired, and the result was interference. Some sort of regulation was necessary, and Congress passed the Radio Act of 1927. The Act established the Federal Radio Commission (FRC) to regulate and oversee radio broadcasting. As a result, the federal government officially retained ownership of the airwaves, but allowed private interests to operate broadcasting facilities under licenses it issued. Provision was made for the renewal of such licenses after three years, depending on the holder’s ability to serve the "public interest, convenience, and necessity".
That same year, the FRC allowed experimental television broadcasting to begin in what had been the "standard" radio band (550-1500 kHz), using a 10 kHz bandwidth. It also allowed television experiments to take place in the 1500-2000 kHz band. As a result of experimentation, 100 kHz bandwidths were recommended in order to provide sufficient picture definition. In 1929, the FRC allocated four channels for experimentation: 2-2.1, 2.1-2.2, 2.75-2.85, and 2.85-2.95 MHz. It also allocated 2.2-2.3 MHz, but specified that it could only be used in the southern and southwestern portions of the country, so as to avoid interference with Canadian radio.
In 1931, the FRC allocated television to what is now the very high frequency (VHF) band. (At the time, it was referred to as the "ultra high" band.) Experimental broadcasts were authorized in the 43-46 MHz, 48.5-50.3, and 60-80 MHz bands with no limits on the bandwidth used.
The Communications Act of 1934 established the Federal Communications Commission (FCC), which replaced the FRC.
No standards had been set for television, and in the 1930s, the Radio Manufacturers Association (RMA) appointed a committee to draft them. At the FCC’s 1936 hearings on television standards, the RMA Allocations Committee recommended that seven channels between 42 and 90 MHz be allocated for television — each with a bandwidth of 6 MHz. The recommendation also included a provision for television experimentation above 125 MHz.
As a result of the hearings, in May of 1936, the FCC allocated three groups of television frequencies: 42-56 MHz, 60-86 MHz, and any two adjacent frequencies above 110 MHz (except for 400-401 MHz).
On 13 October 1937, the FCC allocated 19 VHF channels between 44 and 294 MHz for TV. Each channel was 6 MHz wide. (Apex radio was allocated between 41 and 44 MHz.) The new allocations became effective on October 13, 1938. Twelve of the nineteen channels were above 150 MHz. Those frequencies were thought at the time to be useful only for television relay networks, but some manufacturers thought that the seven channels allocated between 44 and 108 MHz were sufficient for commercial television to begin. On 13 March 1939, the FCC announced new allocations for the higher frequencies. Television was allocated the same nineteen channels it received in 1937. The allocations were effective as of April 13.
The Commission announced that commercial FM broadcasting could begin as of 1 January 1941. In order to make room for it, the VHF band was reallocated. The 42-44 MHz band, previously used by government and educational services was combined with television channel 1 (44-50 MHz) and allocated for FM. What had been TV channel 2 was now called channel 1, and a new channel 2 was allocated to 60-66 MHz.
Television was put on-hold during WWII, but discussions were held with regard to post-war frequency allocations, and on 27 April 1944 CBS proposed a high-definition color system, using channels with 16 MHz bandwidths in the untested UHF band.
The FCC held hearings on the future of the radio spectrum between 28 September and 2 November 1944. The military uses of radio had put new pressure on the FCC to allocate more space in the spectrum to them, and the expected growth of AM, FM and television after the war compounded the problem. The Radio Technical Planning Board testified that an agreement had been reached in which FM radio would be allocated to the 41-56 MHz band, with higher frequencies to be allocated to television.
On 15 January 1945, the Commission announced a proposed frequency allocation plan for frequencies above 25 MHz (VHF). FM was to be shifted upward, with television channel 1 allocated to 44-50 MHz, amateur radio to 50-54 MHz, television channels 2-6 to 54-84 MHz, educational FM to 84-88 MHz, commercial FM to 88-102 MHz, and non-governmental uses to 102-108 MHz. Experimental television was to be moved to the UHF band. Hearings on the matter began on 14 February.
The Commission announced the allocation plan for 25-44 MHz on 21 May, but held off on making a decision on the rest of the VHF band until after FM propagation studies could be made.
Despite objections from Edwin Armstrong and other FM pioneers (including The Journal Co. in Milwaukee), the FCC allocated educational FM to 88-92 MHz, and commercial FM to 92-108 MHz on 27 June 1945. At the same time, it allocated the part of the former FM band, 44-50 MHz, to TV channel 1. TV channels 2-6 were allocated to 54-88 MHz; channels 7-13 to 174-216 MHz.
All was not well, however. CBS continued to push for UHF television. After a meeting on 21-22 February 1946, its Affiliates Advisory Board, adopted a resolution asking the FCC to authorize commercial broadcasting of high-definition, color television in the UHF band. Broadcasters, unwilling to risk the investment in black and white, VHF television, if the industry was to shift to color in the UHF band, balked. The FCC admitted that thirteen channels might be insufficient, and that television might eventually have to be moved to the UHF portion of the spectrum. On 27 September 1946, CBS petitioned the FCC to immediately adopt standards and authorize commercial operation of UHF, color television.
The FCC began hearings on the future of television in December of 1946. In mid-March of 1947, it denied CBS’s petition for color television, stating that it was too early to adopt standards. One of the reasons cited was the bandwidth requirements proposed by CBS. The 16 MHz required would allow for only 27 channels in the UHF band (480-920 MHz). The FCC had as its goal the development of "a truly nationwide, competitive television system", for which it believed more channels were necessary.
Television used a lot of the radio spectrum. Each 6 MHz TV channel could hold five complete AM radio bands. The entire FM band took up only 3.33 TV channels. In addition, stations on the same VHF channel can’t be too close to each other if they are not to interfere. Stations on adjacent channels also have to be separated, by approximately half that distance.
On 6 May 1948, the FCC took several actions, including: banning the sharing of TV channels for non-broadcasting use, and reallocating TV channel 1 for non-governmental, land-mobile use as of 14 June 1948. (Since the public had already purchased a number of receivers, the channels were not renumbered, and the tuners of future sets would start with channel 2.) It also called for a hearing starting on 20 September 1948 on the feasibility of using the UHF band.
Remarks by the FCC’s acting chief engineer John A. Willoughby produced more uncertainty as to the short-term future of television. Willoughby opined that: color television would be available in less than two years, channels 2-6 would be taken away from television and given to fixed and mobile services, channels 7-13 would be used for low-definition television, while the UHF band would be used for high-definition — monochrome and color.
On 27 August, the FCC called for a joint FCC-Industry conference to study the technical problems associated with UHF.
The hearing on UHF began on 20 September, and lasted for three days. At the end of those hearings, the Commission concluded that the matter was more complex than it had originally thought, and that more study was needed. There was a consensus that the UHF band would have to be used, but none as to how. As a result, on 30 September it announced that all television applications would be put in pending files, that no hearings would be scheduled, and that no decisions would be made on cases already heard, until after the questions on channel allocations and assignments were settled
After considering the questions of color, educational channel reservations, and the technical problems associated with UHF, the FCC issued a proposed new frequency allocation and channel assignment plan on 22 March 1951. In it, seventy UHF channels (14-83) were allocated, in addition to VHF channels 2-13. UHF channels would have to be separated by six channels in the same market.
On 14 April 1952, the FCC issued its Sixth Report and General Order, which lifted the freeze on new television licenses as of 1 July, and provided for 617 VHF and 1436 UHF licenses.
The Commission in issuing its Sixth Report and General Order chose intermix VHF and UHF stations in the same cities. That was a mistake. UHF transmitters were not yet as powerful as their VHF counterparts, meaning that their coverage area was smaller. Even when more powerful transmitters became available, using them in the higher frequencies would mean that the electrical power requirements — and expense — would be prohibitive. In addition, there was no requirement that manufacturers produce sets capable of receiving both bands, and those who already owned sets would have to purchase UHF converters. Those converters were not particularly good at receiving a UHF signal. Indeed the state-of-the-art was such that UHF tuners weren’t very good. They did not have good selectivity, and could not "lock in" on a channel the way VHF tuners could. UHF tuners were continuous like a radio dial.
That meant that UHF stations were at a disadvantage in markets which had strong VHF competitors. In order to attract advertisers, the UHF stations had to get their signal to as many viewers as possible, and that meant that they needed more powerful transmitters. It also meant that they had to convince viewers to purchase UHF converters or all-channel sets. UHF broadcasters were in trouble.
Many UHF stations in intermixed cities either turned in their construction permits after never going on the air, or went dark within a short period of time. Congress held hearings on UHF in 1954, but no action was ever taken, and much of the UHF spectrum went unused.
From 1952-1962, the FCC would propose various plans to de-intermix a number of cities. In 1956, it considered a plan to shift all television east of the Mississippi River to UHF, while that in the West would be predominantly VHF. The VHF stations in Milwaukee reacted negatively, and the plan was never implemented.
Complicating matters, in early 1957 the military sent a formal request to President Eisenhower (who has the power under the Communications Act of 1934 to make allocation decisions in matters of national security) for TV channels 2-6. The request was denied.
As of 30 June 1962, 508 VHF stations were in operation, but only 104 UHF, of which 44 were educational. Since 1952, approximately 100 more UHF stations had gone dark.
FCC Chaiman Newton Minow made the passage of an all-channel receiver bill the number one legislative priority of the FCC for 1962. The proposal to de-intermix some cities was used as leverage to get the law passed. Congress did so, and on 10 July 1962, President Kennedy signed into law the All-Channel Receiver Act. The law affected all sets manufactured after 30 April 1964, and required that all sets shipped via interstate commerce (or imported) include the capability of receiving a UHF signal.
However, the all-channel law did not drive up interest in UHF. Much of the spectrum still went unused. In 1963, channel 37 was allocated to radio astronomy, and no stations were allowed to use it as of 1 January 1974. (No over-the-air television station had ever done so. In 2000, it was allocated for use by low-power medical telemetry equipment, in addition to radio astronomy.) It wasn’t until the 1970s that UHF tuners were developed by Japanese manufacturers that could "lock-in" a UHF signal the way VHF tuners could. Legislation later required that all UHF receivers be equipped with such tuners. As a result, interest in UHF increased.
Since 1945, the FCC was under pressure from land-mobile and emergency service users for more spectrum space. In July of 1968, it proposed rulemaking which would have allowed land-mobile users to operate on UHF channels 14-20 in the top twenty-five markets, if they were not being used by television (channel sharing). It also proposed that TV channels 70-83 be reallocated for land-mobile use. Comments were requested by 2 December of that year, and replies to those comments by 31 January 1969. On 20 March 1970, they voted down that part of the proposal that would have allowed the sharing of channels 14-20. In May of that year, the Commission finally resolved the issue, by passing a modification to their proposal, which allowed land-mobile users to share one or two of channels 14-20 in the top ten markets. It also voted to reallocate channels 70-83 for common carrier and private land-mobile use. Since that would displace television translators (which had been assigned to the channels since the late 1950s), it proposed opening up channels 14-69 for that use.
Meanwhile, technology progressed such that the UHF band could finally be accessed by land-mobile users. Channels 70-72 are now used by pocket pagers and Nextel’s SMR band. Channels 73-77 are used by cellular and mobile telephones. Channels 77-80 are used by public safety and channels 80-83 by cellular telephones and base stations.
On 1 September 1981, the Los Angeles County Sheriff’s department filed a request with the FCC which would’ve reallocated TV channels 14-20 for public safety and other land-mobile uses. Several law-enforcement and state agencies later joined in the request, including the Florida Division of Communications, which recommended that the Commission relieve potential congestion by allowing land-mobile radio operations on unlicensed television channels 14 through 20 nationwide, on a noninterference basis with existing television stations. The National Association of Broadcasters, the Association of Maximum Service Telecasters, and the National Association of Public Television Stations opposed the request.
Normally, when the FCC granted a broadcaster a construction permit, they were given the channel for free. After the Commission took UHF channels away from TV, they were auctioned off, resulting in billions of dollars in revenue for the federal government. In the mid-1980s, the FCC threatened to do the same with more of the UHF spectrum, which was still unused. Television broadcasters were loath to give up more of their spectrum, and they responded by digging up an argument from the past — the need for more bandwidth for high-definition television.
As a result, studies were conducted during the 1980s and 1990s. Finally, a set of standards was developed which called for digital, rather than analog television broadcasting. Digital broadcasting had a number of advantages, one of which was that stations in the same market could now be on adjacent channels. Analog signals required that such stations be separated by either two (VHF) or six (UHF) channels. As a consequence, spectrum could be taken away from television and reallocated for other uses.
After Congress passed the Telecommunications Act of 1996, the FCC promulgated a licensing regime for digital TV (DTV). The act provided that the FCC should restrict the issuance of DTV licenses to existing broadcasters — either licensees or those holding construction permits (effectively freezing new DTV applications). The digital signals were compressed into the old 6 MHz channel bandwidths. In an unprecedented move, full-service television stations were given a second channel on which to broadcast digital signals during the analog-digital transition period. Once DTV was fully established, those existing analog broadcasters would have to surrender one of their licenses. (Low-power and Class A stations can make the switch at any time, but it makes no sense for them to do so until their full-service counterparts do, as they have not received a second channel.) The Balanced Budget Act of 1997 ordered that at the end of the transition period, four of the channels between 60 and 69 were to be allocated to public safety, while the others were to be auctioned for commercial use.
In much the same way that sets equipped to receive UHF signals weren’t popular outside of major UHF markets, sets equipped to receive a digital over-the-air signal did not sell well. The date on which the transition was to occur was to have been 31 December 2006, but the law establishing it had a loophole which allowed analog transmission to continue if not enough consumers in a given market (85%) were able to receive a digital signal from some source: over-the-air, cable or satellite. Pressure mounted. The September 11th Commission in its final report recommended that:
"Congress should support pending legislation which provides for the expedited and increased assignment of radio spectrum for public safety purposes."
Additional spectrum for that use would have to come from the unused UHF channels. The Deficit Reduction Act of 2005, required all analog television broadcasting to switch to digital by 17 February 2009, and expanded the number of channels to be "recovered". On 20 December 2005, the U.S. Senate passed a version of the bill, after Vice President Dick Cheney flew back from a Middle East trip to break a 50-50 tie. On 1 February 2006, the House of Representatives passed the bill, and it was signed into law by President George W. Bush on 8 February 2006. As a result, channels 52-69 will be given to emergency services, or auctioned after the transition to digital TV is completed.
Ironically, UHF is more desirable for broadcasting a digital signal, and most Milwaukee television stations will shift to that portion of the spectrum. Most viewers receive their signal via cable or satellite, but those who still want over-the-air television will have to purchase receivers with digital tuners, or converters.
Digital compression allows broadcasters to transmit a high-definition picture, or a number of programs over sub-channels using the 6 MHz bandwidth. It also allows for the transmission of other information, and will potentially give viewers a degree of interactivity like they have not experienced before.
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Call Letters
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Analog Channel
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DTV Transition Channel
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Permanent DTV Channel
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WTMJ-TV
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4
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28
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28
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WITI
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6
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33
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33
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WMKE-CA
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7
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(None)
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20
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|
WMVS
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10
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8
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8
|
|
WISN-TV
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12
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34
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34
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|
WVTV
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18
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61
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18
|
|
WCGV-TV
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24
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25
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25
|
|
WVCY-TV
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30
|
22
|
22
|
|
WMVT
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36
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35
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35
|
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WBWT-LP
|
38
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(None)
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31
|
|
WMLW-CA
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41
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(None)
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13
|
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WJJA
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49
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48
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48
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WWRS-TV
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52
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43
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43
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WPXE
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55
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40
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40
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WDJT-TV
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58
|
46
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46
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WYTU-LP
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63
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(None)
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17
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