This is the General History Section of
The Broadcast Archive

Maintained by:
Barry Mishkind - The Eclectic Engineer


by Mark Durenberger
Minneapolis, Minnesota

This is the fifth in a series of six articles about the history of clear-channel AM radio stations.

Last time, we discussed the FCC’s landmark 1961 Report and Order that duplicated 13 of the 25 1-A clear channels. It wasn’t long before Class II stations began turning up in the Western states. Nighttime radio reception would be changed forever.  In that Report and Order, the FCC noted the remaining 12 unduplicated 1-A channels would be protected for only three more years while it considered potential “super-power.” It temporarily froze all applications that might conflict with super-power operation on those 12 channels. The 1961 FCC vote was not unanimous. Commissioner Robert E. Lee’s voice was heard in strong dissent; he continued to advocate super-power as the correct approach to nighttime “white-area” coverage.  In spite of Lee’s eloquence, momentum was building toward the breakdown of the remaining 12 clears.

 The 1961 order was a significant victory for opponents of the clear-channel broadcasters, but the order triggered an avalanche of reaction. Attorneys and lobbyists stalking the halls of Congress are expected as a matter of daily political life. Groundswell opinion from the masses is another matter and there may be no advocacy tool more effective than a 50-kW powerhouse exhorting its listeners to “contact your congressman so your radio service doesn’t go away.”  The Clear Channel Broadcasting Service launched a massive publicity campaign and political crusade.  Bills were introduced in Congress to stop the 1-A duplication and to authorize super-power. In the end, they didn’t pass. The other side had a larger voice.

Another super try

Meanwhile Congress stirred the pot via HR 714, suggesting that the FCC grant a one-year stay of the 1961 order, “to allow all Class 1-A clear channel stations to file for higher power.”  Some clear-channel broadcasters responded immediately. The record shows the following activity:

Oct. 17, 1962: WLW(AM) applied for 750 kW on 700

Oct. 18, 1962: WJR(AM) applied for 750 kW on 760 (KFMB agreed not to protest)

Oct. 20, 1962: WSM(AM) applied for 750 kW on 650

Nov. 12, 1962: WGN(AM) applied for 750 kW on 720

Nov. 16, 1962: WHO(AM) applied for 750 kW on 1040

These applications were all denied a few weeks later, the commission saying that super-power could only be authorized through the process of rule making. In response, the CCBS immediately sought such a rule making, “to permit power in excess of 50 kW by all Class 1-A stations.”  The CCBS request and others before the FCC would be disregarded for more than a dozen years. HR 714 accomplished nothing.

The 1-A stations tried other approaches.  In 1963, WLW and KSL filed applications for experimental authorization, at powers of 750 and 500 KW respectively. In that same year at least two stations, WGN and WJR, went before a court of appeals to challenge the FCC order denying their super-power applications. The courts turned them down.  In a separate request, dated June 19, 1964, WCCO, citing its “critical Civil Defense obligations,” filed a petition for rule making asking for 750 kW “developmental/test authority” on 830. The FCC returned the WCCO application on July 2, 1967.  All of these filings for super-power were attended by exceptional publicity generated by the applicants.  The CCBS pulled out all the stops, suggesting national defense communications would be imperiled and noting that super-power authorizations would put the United States in a better bargaining positioning with the Mexicans, with respect to that country’s “Border Blasters.”

In 1962 the FCC reaffirmed its 1961 order duplicating 13 of the clears.  They reiterated the goal of providing “at least four dependable night-time signals to the entire country”.  They saw the problem as follows: “Is white-area night-time service best achieved by adding duplicate stations on the 1-A channels, or by permitting high power on a few “national stations”?  Of course there was another solution available, but the FCC still wouldn’t consider FM as a radio service and it ignored NBC’s proposal that the commission authorize FM stations in the white areas, in lieu of duplicating service on the AM clears. 

Again, Commissioner Robert E. Lee dissented strongly. He continued to promote super-power and suggested the majority of the commissioners were “sparring with windmills” in their rush to a duplication of the clears.  The lobbying and maneuvering would go on for another 18 years! Most of the members of the Clear Channel Broadcasting Service urged their listeners to turn up the heat on their congressmen, “so you don’t lose your Full Service Radio.”  Clear-channel stations broadcast promos around the clock and published “educational” literature supporting “the protection of full-service radio.”

Super-power at last?

While the broadcasters worked to stir up public reaction, the FCC seemed to be doing its part to nourish the angst.  In 1966 the commission staff suggested publicly that 650, 830, 870, 1040, 1160 and 1200 “best met staff criteria for use of super-power.”  That sent a signal to the industry that the issue was still alive.  And one day in late 1975, the FCC issued yet another trial balloon. The headline in the Washington Star read “FCC Ready to OK Super-Power Radio on 10-12 Channels.” The story quoted FCC sources and made it clear that super-power authority was indeed a possibility. 

Two weeks later the commission announced Docket 20642, re-opening the clear-channel inquiry that had been terminated with the Report and Order of 1961. The commissioners planned to deal with the super-power requests from CCBS, WSM, WCCO, WWL and others that had been on file for more than a decade.  Their intent was to finally bring the entire clear-channel matter to a conclusion, but it would be five years more before the FCC completed the destruction of night time clear-channel service. The 1975 notice asked for extensive and qualitative data to support the coming judgment. To evaluate actual listening conditions, the Clear Channel Broadcasting Service commissioned nighttime listening tests of all 1-A stations.  Station engineers recorded each other at night and prepared the tapes for submission to the FCC.

In re-opening the matter, the FCC also asked for information on the potential social and economic impact of operation in excess of 50 kW. Among the issues was the FCC’s concern that super-power would place an undue concentration of influence in the hands of a few; that this could impact the national advertising picture and perhaps even hinder the ability of smaller stations to secure network affiliations. Music to the ears of the opposition!

The 1975 notice also asked the 1-A licensees to declare whether, and at what level, they would apply for super-power, if that were the recommended solution. On the flip side of that coin, the FCC asked for comments on whether it should simply eliminate sky-wave protection altogether on the 1-A channels.  This unfortunate proposal was stimulated by certain congressmen goaded into action without the benefit of engineering realities by the Daytime Broadcasters’ Association.

Clearing the air

The 1975 docket was the beginning of the end of clear-channel operation and the final trauma in a matter nearly half a century old. With the stakes involved, the paper record was incredible. In response to the 1975 proceeding, many early ideas on how to serve white areas were dusted off, refined and resubmitted.  Among them was a proposal to use the band 150 to 185 kHz for extended ground-wave coverage.  The Corporation for Public Broadcasting, looking for frequencies, suggested a reduction in channel spacing to 9 kHz or even 8 kHz and suggested expanding the band above 1600 and below 540 kHz.  The NAB even suggested using FM translators to extend AM coverage! And for the first time, the FCC suggested in its 1975 notice that FM might be included in calculating nighttime service areas.

And the Daytime Broadcasters Association was back. This time they proposed an extension of Pre-Sunrise and Post-Sunset Authority. Later, they would propose breaking up the clears to provide additional Class IV local stations, even suggesting that 1-A operators should not be protected beyond their “home market.”

In response to general questions about interference, respondents suggested the best way to combat rising interference would be across-the-board power increases “on all channels except the 1-As and 1-Bs.”  AT&T weighed in on the question of interference that might be caused by super-power, suggesting that AM super-power would cause “unacceptable interference to telephone equipment.” 

Emotions and unfortunate proposals aside, the official record would morph into some thoughtful technical analysis.  The issues under consideration for a possible super-power environment included blanketing, self-interference and adjacent-channel interference. Also discussed were the potential effects of non-ionizing radiation and a sky-wave cross-modulation effect variously labeled the “Amsterdam” or “Luxembourg Effect.” (It had been demonstrated that high-power RF actually changed the levels of ionization in the atmosphere and even caused plasma wave generation.)  High-power advocates countered NIR concerns by commissioning a study by Fritz Leydorf, a P.E. who took part in the original WLW high-power work. Leydorf went into great detail about how “folks had lived and worked near the high RF fields and apparently felt no ill effects.”

In our final installment we’ll see how all the brouhaha turned out.

Mark Durenberger  welcomes questions and comments about this series via e-mail to