Lumbard, Chief Judge, and Friendly and Anderson, Circuit Judges.
As a result of proceedings in several courts of appeals unnecessary to detail we have before us a number of petitions, under 28 U.S.C. § 2342(1), for review of orders of the Federal Communications Commission, reported in 8 F.C.C.2d 698 (1967), and 10 F.C.C.2d 283 (1967), which amend Part 73 of the Commission's Rules so as to establish a changed pattern for presunrise operation by certain classes of AM radio stations. While the petitions raise many substantial questions, both substantive and procedural, which have demanded extensive consideration and discussion, we sustain the Commission.
From its very beginning, federal regulation of standard AM radio service has been complicated by the fact that radio waves do not act in the same way when the sun is up as when down. During the day, the part of the radio signal directed skyward (the "skywave") is dissipated in the atmosphere, and only the portion moving parallel to the ground (the "groundwave") provides useful service. At night, however, the ionosphere reflects the skywave signal back to earth, and if the skywave is strong enough, a station can land an audible signal in large areas that its ground wave does not reach. This, however, is not an unmixed blessing. If the skywave lands in an area already receiving service from another station on the same frequency, the two signals may destroy one another so that only garbled noises will be audible.
The Commission has attempted to fashion a nighttime allocation pattern that will maximize the number of listeners who will benefit from skywave service and yet permit as many listeners as possible a wide choice of program, preferably of nearby origination. The AM band has been divided into three parts for these purposes. On 46 Clear Channels wide area service is the Commission's dominant goal. Twenty-four of these channels are occupied by one Class I-A station of high power, whose skywave and groundwave are given maximum protection. 47 C.F.R. § 73.25(a) (1967). At the most, only one other station in Class II is permitted to operate at night on these channels, and the power and direction of the subordinate station's signal is limited so that it will not cause undue interference. Other Class II stations occupying these channels are limited to daytime broadcasting, where the skywave is of no concern. The other 22 Clear Channels are intended to serve the same purpose as the ones we have just discussed. They differ only in that each is occupied at night by two or more dominant stations in Class I-B and, often, by several subordinate stations in Class II.*fn1 The overwhelming majority of the Class II stations, however, are limited to daytime broadcasts.*fn2 By this careful allocation pattern, the Commission has succeeded in providing skywave radio service to some 20,000,000 persons who would not receive any groundwave signal at night.
Complementing the Clear Channel stations are the stations of moderate power in Class III that are located on 41 "regional" channels. These stations are expected to provide large numbers of listeners with one or more programs originating closer to home. Since many more stations occupy a given channel at night, regional broadcasters generally do not have a usable skywave service. 47 C.F.R. § 73.182(e), (v) (1967). Steps must be taken, however, to guarantee that one station's skywave signal will not interfere with another's groundwave. Consequently, of the 858 Class III stations permitted to operate by night, only 90 operate with the same facilities they are allowed to use by day. Moreover, 1200 additional Class III stations are restricted to daytime only broadcasting to insure against interference.
To supplement the services provided by the regional broadcasters, a large number of low power Class IV stations are assigned to six local channels. Their night operations are limited in a similar manner.
The Commission's Earlier Efforts as to Presunrise Operation.
The shift from nighttime to daytime ionospheric conditions does not take place the instant the sun rises; instead, the skywave signal weakens gradually from two hours before dawn, and it is not until two hours after sunrise that true daytime conditions exist. It is the Commission's effort to regulate broadcasting during the transitional presunrise period with which we are here concerned. In 1941, the agency promulgated special rules, which remained substantially intact until the rule-making proceeding now under review, to govern the conflicting interest of daytimers and fulltimers during the pre-dawn hours of transition. Under old rule 73.87, quoted in the margin,*fn3 all restricted stations, except for those in Class IV and certain ones in Class II, could begin broadcasting at full daytime power from 4 A.M. If, however, undue interference to fulltime stations resulted, the Commission had the right to suspend such pre-dawn operations summarily, pending a hearing on the interference question. Music Broadcasting Co. v. F.C.C., 95 U.S.App.D.C. 12, 217 F.2d 339 (1954). Although the principal beneficiaries of the rule were Class III stations whose nighttime operations were limited or banned entirely, a substantial number of Class I-B and Class II stations took advantage of its provisions as well.
While this system worked relatively well during its early years, it was subjected to increasing strain as the number of AM stations increased from 882 in 1941 to the present 4250, and the number of daytimers mushroomed from 60 to 2180. Interference complaints from dominant fulltimers naturally increased, leading to summary termination of the daytimers' pre-dawn services. Indeed, some of the fulltimers on the particularly crowded regional channels indicated they would complain more often but for the fact that the airwaves had become so full that it was impossible to identify the interfering daytimer within a reasonable period of time. Moreover, it was reasonable to expect that the fulltimers would exercise increasing vigilance over their channels for the presunrise hours had taken on a new economic importance in an era in which the largest radio audiences were to be reached during the time America was driving to work.
The daytimers, too, were becoming increasingly restive with the terms of a compromise which promised to become increasingly unfavorable to their interests. In 1957, the Commission began a study of a proposal, sponsored by their Association, which would have given them the right to operate from 5 A.M. to 7 P.M. regardless of the amount of interference this would cause the dominant fulltimers. This was rejected in 1958, Daytime Standard Broadcast Stations, 17 R.R. 1669. A somewhat more modest proposal, permitting operation from 6 A.M. to 6 P.M., suffered a similar fate a year later, Extended Hours for Daytime Operation, 26 F.C.C. 53.
In 1960, however, the old regime was again put into question when the Senate ratified a new North American Broadcasting Agreement which, as we shall describe at a later point, made it clear that the presunrise operations of at least half of the stations taking advantage of Rule 73.87 were in violation of our international commitments. In response to the treaty and to the complaints of the fulltimers, the Commission issued a Notice of Proposed Rule Making on December 6, 1961, which initiated the proceedings now under review. This proposal would have revised the status quo in the fulltimers' favor. The plan would have forbidden presunrise broadcasting by all restricted stations, except those Class III stations already operating. As to these, the Commission proposed new rules which would have made it much easier for dominant stations to establish their interference claims.
The daytimers were not inactive in the face of this threat. On July 2, 1962, the House of Representatives passed a bill, H.R. 4749, which would have permitted daytimers of whatever class to begin broadcasting at full power at 6 A.M., or 4 A.M. if they had done so before, where there was no fulltimer operating in the same community. Affected fulltimers were required to make a substantial showing of interference before they would have a right to a hearing and this, unlike the summary procedure under Rule 73.87, would lead to termination of the daytimer's service only if the Commission found that the latter did not better serve the public interest.*fn4
In response to this legislative effort, which the agency opposed and which died in the Senate, the Commission issued a Further Notice of Proposed Rulemaking. This sought to recognize the daytimers' claim, aired both in Congress and in the prior rulemaking proceedings, that because they broadcast information of great importance to their local communities, they should be permitted to broadcast during the early morning hours regardless of the interference this would cause the fulltimers, whose broadcasting could not take into full account the needs of all the communities that were dependent upon them at night. The Commission recognized, however, that though the local service of the daytimers was valuable, these stations could not be permitted to broadcast during the pre-dawn hours on the same basis that they did by day. For the studies it had made in its prior proceedings indicated that, because of skywave interference, the number of listeners who would be deprived by interference of service provided by the fulltimers would "far exceed" the number of listeners who would gain by the distinctive character of the daytimers' local coverage. Consequently, to cut down service losses to an acceptable figure, the Commission proposed to limit the daytimers' presunrise operation in four ways. First, it would permit only those daytimers located in a community which was not served by a local fulltimer to operate before dawn. Listeners located in other areas, it reasoned, already had access to early morning local news. Second, it proposed that the daytimers' power should be no more than 500 watts during the transitional period. This, it suggested, was enough to reach the local community. Third, daytimers could not begin operating before six in the morning. Finally, the dispensation was limited to those daytimers in Class III who occupied regional channels on which fulltimer skywave service was not a factor. As for Class II daytimers, occupying "Clear Channels," a different regime would apply. Only those daytimers located to the west of all dominant Class I stations could broadcast before dawn but, in contrast to the system for Class III, no fixed starting time or power limitation was set. Rather daytimers in this class could begin operations at the time the sun rose at the westernmost Class I station -- for at that time much of the dominant station's skywave would become useless.
Comments were invited and some 300 stations responded formally, as did the associations representing interested groups of fulltimers and daytimers. On June 28, 1967, after negotiating a supplementary agreement with Canada consistent with its disposition, the Commission reached its decision, which, in general, favored the daytimers more than its original proposal. While the limitations on starting time and power*fn5 were retained for Class III stations, all daytimers of this class were permitted to take advantage of the new rule. The new dispensation was also broadened to include the many Class III fulltimers whose operations were restricted at night, thereby permitting them to offset in some cases the impact of the increased interference the daytimers would cause. Class II stations were treated much more restrictively, in keeping with the Commission's effort at maintaining the integrity of skywave service on Clear Channels. Class II stations located on a I-B channel, which under FCC regulations may be authorized to broadcast during the day with up to 50,000 watts power, could begin their daytime broadcasting at 500 watts at 6 A.M., provided this was later than sunrise at the westernmost Class I station to the east. However, one important limitation on this authority was imposed -- only such power could be used as did not interfere with the skywave service provided by the dominant stations located to the west, where the sun had not yet risen. Class II stations operating on a domestic I-A channel were treated differently. If they were located to the east of the dominant station, no presunrise operations were to be permitted at all; if to the west, they could begin operating at full daytime power from 6 A.M. or sunrise at the dominant station (whichever was later), pending decision in another proceeding as to whether a limitation on power was appropriate on these channels as well.
Thus, the Commission's decision alters the prior allocation pattern decisively. Limited pre-dawn broadcasting rights are granted daytimers on a broad scale where formerly more ample privileges had been granted on the sufferance of the increasingly vigilant fulltimers.
The Positions of the Parties
Like all compromises this has not succeeded in pleasing everybody. Some fulltimers complain that daytimers are allowed to operate too much and some daytimers complain that they are allowed to operate too little. Specifically WBEN, a full time Class III station, and the Association of Broadcasting Standards, Inc. -- a group representing Class II and Class III stations operating both day and night -- object insofar as daytime operation is permitted from 6 A.M. regardless of the amount of interference to a fulltimer's signal this might cause. On the other hand, a number of Class II and Class III stations, whose operations are either limited*fn6 or banned*fn7 at night, protest because they had previously been broadcasting between 4 A.M. and sunrise at their full daytime power and the decision has forced them to curtail their operations although no fulltimer has complained of their causing undue interference. A third group of stations have intervened in support of the order.*fn8 Their position is explained by the fact that when the Commission inaugurated these proceedings, it forbade any new restricted stations licensed after January 29, 1962, ...