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 fourth in a series of 6 articles about the history of clear-channel AM radio stations.  

Once past the 1941 North American Regional Broadcasting Agreement, or NARBA, the FCC began to focus on ways to provide better nighttime radio coverage of under served “white areas.”  The choice seemed simple but dramatic: Add duplicate stations on the AM clear channels, or authorize existing 1-A stations to operate with power in excess of 50 kW, in an attempt to provide solid service over wider areas.  (The FCC still refused to include FM in its coverage calculations.)

Imagine the hullabaloo in Washington! In one ring, communications engineers and lobbyists asserting that additional stations on the clears would create interference that would “destroy a national asset”.  On the other side were the folks who wanted an end to what they called the “monopoly” and “unfair advantage” held by clear-channel broadcasters. In the middle were beleaguered commissioners who, in the view of many staffers, weren’t tuned into the issues but were noted for being responsive to political pressure.

Absent the hard data needed to make a defensible decision, the FCC continued its “trial balloon” approach to resolving the clear-channel matter. In 1958 the FCC proposed new Class II stations on 23 of the clear channels (660 and 770 were already considered duplicated). At this same time, the FCC asked the 1-A stations to make their case for super-power in excess of 50 kW “if it were authorized.”  Among those responding was WCCO, which filed comments and a complete engineering exhibit in support of 750 kW. They planned to directionalize west from Minneapolis on 830, and said this would provide significant white-area coverage gain not available through the FCC’s other proposed solutions.  (WCCO believed so strongly in the value and logic of its engineering data that it purchased land for a four-tower array to include a true Franklin antenna and began negotiating for the necessary usage permits).

1961 Report and Order

The matter came to a head in 1961, with the publication of a “Report and Order: In the Matter of Clear-Channel Broadcasting in the Standard Broadcast Band.” It was a landmark edict.  Until then, with two exceptions, only one station operated at night in the contiguous 48 states on each of 24 1-A channels (the 1961 rule making would add 1030 as the 25th 1-A channel). That Report and Order authorized duplication on 13 of the 1-A frequencies, assigning one new Class II station to each channel, to operate with a minimum of 10 and a maximum of 50 kW at night. (Interestingly, in some cases, Class II stations operated with lower power during the day, to protect existing adjacent-channel daytime services.)

These new Class II stations would be allocated to western states, to serve the white areas. The initial duplication table is shown in Fig 1.  The 1961 Report and Order contains some interesting language. In an intriguing way of hinting at the inevitable, instead of explaining how they chose which channels to duplicate, the commissioners chose to describe instead why they had spared the remaining 12.  Here, in the FCC’s words, which are italicized, are their reasons for protecting those 12 1-A channels as potential super-power candidates:

640: “Serves the west; Super-power could cover a lot of white area.” KFI might operate 750 kW as a DA-1, oriented 22 degrees. But since 1944, 640 had been duplicated in Ames, Iowa, by WOI, under a series of STAs permitting nighttime operation.

650: “Super-power could cover a lot of under-served area in the southeast.” The commission said WSM might operate 750 kW, DA-N at 135 degrees. 

660: Because 660 was duplicated in Fairbanks, it was “protected for now against further duplication.” While 660 might be available for super-power, such a station would not be authorized in New York, because it would need to protect 650 and 670, requiring directionalizing north and southeast, into areas already well-served.

700: “Super-power could cover a lot of under-served area in the southeast.” WLW could operate 750 kW DA-1 at 180 degrees. Interestingly, the FCC also said 700 might be available for both super-power in Cincinnati and duplication in Utah.

750: This had been assigned to Alaska for duplication, to allow Anchorage to surrender 730 to the Mexicans. WSB, citing the distance to Alaska, asked the FCC to protect 750 as a U.S. super-power channel. This request was denied at first, but in response to a later Petition for Reconsideration, in 1965 the commission granted the protection, making it clear that this did not imply higher power would in fact be authorized.

820: “Serves the west; super-power could cover a lot of white area.” The FCC said WBAP could operate 750 kW DA-N at 270 degrees. 

830: “Super-power could expand service in the Midwest.” But this channel too was already partly duplicated. WNYC had been on the air in New York City since 1943, under limited nighttime authority. The 1961 Report and Order made the New York authorization “permanent.”  This meant that in a super-power application, WCCO would have to limit its nighttime power to the East.

840: “Super-power could cover a lot of under-served areas in the southeast.” WHAS could operate 750 kW DA-N at 135 degrees.

870: “Super-power could cover a lot of under-served area in the southeast.” The FCC said WWL could operate 750 kW DA-1 at 0 degrees.

1040: “Super-power could expand service in the Midwest.” WHO could operate 750 kW DA-1 at 270 degrees. But if 1040 was good for the Midwest, why not 1120? Because KMOX at super-power on 1120 would cause unacceptable interference to adjacent-channel 1110 and 1130 stations.

1160: “Serves the west; super-power could cover a lot of white area.” The FCC suggested KSL could operate 750 kW, non-directional.

1200: “Serves the west; super-power could cover a lot of white area.” WOAI could operate 750 kW DA-N at 337 degrees.

Had these stations been granted super-power, directionalized on the bearings suggested, imagine how the AM band might have sounded!

The Clear Channel Broadcasting Service had been doing yeoman’s work in assessing the various technical proposals before the FCC and ensuring that its own position was understood.  Led by WSM’s Jack DeWitt, the small but enterprising CCBS technical group filed Comments proposing a “gang of 20” channels for 750 kW operation.  These included 640-650, 680, 700, 720, 750, 810-850, 870, 890, 1020-1040, 1160, 1180, 1200 and 1210. In being so specific by frequency in its comments, the FCC may have been responding to this CCBS proposal.

The 1961 Report and Order provided other information of interest:

·         To protect itself on 760, WJR had suggested to the commission that 760 be duplicated only in Hawaii. The commission didn’t buy that one. 760 had been assigned for use in San Diego, to allow KFMB to vacate 540 for use by Mexico. In this instance, the FCC displayed its pragmatic side by granting itself some waivers; most notably reducing the protection criteria for KBIG/740 Avalon, for the interference that would result from a San Diego operation on 760.

·        The commissioners also reviewed an ill-timed proposal by KBIG that 830 be duplicated in Southern California. The idea was that if KFMB were given 830 instead of 760, this would resolve the KFMB/KBIG interference problem (while also solving WJR’s concerns about a domestic co-channel operation on 760).

 Alternatively, KBIG said, “if KFMB were to be assigned 760, why not move KBIG from 740 to 830?” That too would resolve the 760/740 interference problem. The commission said “no dice,” and stuck to its earlier ruling that 760 would come alive in San Diego. 830 would continue to operate from Minneapolis (with a the secondary operation in New York City), and 830 would suffer no further duplication at this time.

  The FCC also carried over without resolution the long-standing “WCCO-WNYC” battle.

 ·        1030, which had been a 1-B channel reserved for duplication in New Mexico, would now become a duplicated 1-A channel and opened to operation in Wyoming, pending resolution of the famous “KOB Case.” (That story, the “WCCO-WNYC 830 fight” and other related stories will be the subject of follow-up reports.)

 ·        The commissioners also cut through a myriad of pleadings and population statistics to reaffirm that super-power on the Chicago 1-A stations “was not needed to provide new national night-time service.” They said “additional stations in the West on the 4 Chicago frequencies (670, 720, 780 and 890) would better serve Western listeners.”

 Ironically, in the ultimate resolution of the clear-channel matter, the Chicago stations, by virtue of their central location, probably ended up with more protected land coverage area than many of the 1-A stations located near either coast.  That 1961 Report and  Order was a major milestone and a significant victory for the opponents of clear-channel authority. But the clear-channel operators weren’t about to capitulate.

 Next time: Congress gets into the act.




Frequency                    New Status               New (Existing) Assignment

640                              Protected, but:             (Duplication in Iowa)
650                              Protected                   
660                              Protected, but:             (Alaska existing)
670                              Duplicated                   Idaho NEW
700                              Protected                   
720                              Duplicated                   Nevada NEW
750                              Protected, but:             (Alaska existing)
760                              Duplicated                   San Diego for KFMB move
770                              Duplicated                   (“The KOB Case”)
780                              Duplicated                   Nevada NEW
820                              Protected                   
830                              Protected, but:             (Duplication in New York)
840                              Protected                   
870                              Protected                   
880                              Duplicated                   Nebraska NEW
890                              Duplicated                   Utah NEW
1020                            Duplicated                   New Mexico NEW
1030                            Duplicated                   Wyoming move of KTWO (“KOB case”)
1040                            Protected                   
1100                            Duplicated                   Colorado NEW
1120                            Duplicated                   California or Oregon NEW
1160                            Protected                   
1180                            Duplicated                   Montana NEW
1200                            Protected                   
1210                            Duplicated                   Oklahoma NEW


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