This appeal emanates from the Federal Communications Commission’s denial of an application seeking authority to construct facilities enabling a radio station to change from daytime-only to unlimited-time broadcasting. The reason for the denial was the Commission’s view that the applicant was unable to fully comply with the Commission’s rule prescribing the minimum coverage of the city of license which the service applied for must provide. Among the questions tendered for our decision are whether, in holding that the rules intercepted the applicant, the Commission remained faithful to relevant but unmentioned precedents, and whether, in denying the applicant a waiver of the rules, the Commission gave proper weight to the fact of black ownership and operation of the applicant’s station. Answering both questions in the negative and reaching no other issue, we remand the сase to the Commission for further consideration.
I
Radio Station WEUP, licensed to Garrett Broadcasting Service, 1 transmits from Huntsville, Alabama, on 1600 kHz with 5-kilowatt power on a daytime-only basis. Station WRBN, licensed to WRBN, Inc., broadcasts daytime-only on 1600 kHz with 1-kilowatt power from Warner Robins, Georgia, 220 miles southeast of Huntsville. Each licensee applied to the Commission for a permit authorizing construction of a 500-watt directional facility for nighttime use.
The Commission consolidated the two applications for comparative hearing, 2 following completion of which an administrative law judge concluded that WEUP’s proposed nighttime service would not meet the Commission’s coverage rules 3 and that the attendant circumstances did not warrant a waiver of their demands. 4 Although WRBN’s project likewise fell short on coverage, the judge deemed its showing on that *1058 score substantial enough to justify waiver of the deficienсy. 5 On administrative appeal the Commission’s Review Board sustained these positions, 6 and the Commission, one member dissenting, declined further review. 7 The appeal to this court 8 followed, presenting solely the question whether the rulings on coverage and waiver were free from error.
When WEUP filed its application, the Commission required “[t]he transmitter *1059 of each standard broadcast station [to] be so located that primary service is delivered to the borough or city, in which the main studio is located in accordance with the [Commission’s] rules and regulations. . . . ” 9 The Commission also required, as it does now, that as an element of transmitter site “[a] minimum field intensity of 5 to 10 mv/m shall be obtained over the most distant residential section.” 10 The administrative law judge found, and the Review Board agreed, that WEUP’s projected 5 mv/m nighttime contour would include only 73.4% of Huntsville’s total population and 49% of its total area. 11 Neither the judge 12 nor the Board 13 considered WEUP’s grounds sufficiently impressive to warrant a waiver of the city coverage requirements.
In this court, the parties have engaged in extensive debate on a number of points and subpoints, some of which we need not consider. For we find that in two broad respects the Review Board 14 erred to the extent that the case must be given further attention administratively on both the coverage and waiver issues. We discuss the difficulties making that necessary 15 and, without intimating a view on any other claim, we remand the case to the Commission for additional proceedings.
II
During the last quarter-century, Huntsville has experienced a tremendous geographical expansion. From aerospace industry and the resultant annexation of contiguous areas, 16 it had grown nearly 25-fold to 105.6 square miles in 1970. 17 In the process, the city has become very irregular in shape, stretching to a maximum of about 20 miles from north to south and about 15 miles from east to west. 18 Over the years from 1958, when WEUP commenced operatiоn, its ability to cope with these changing conditions has gradually diminished. Not surprisingly, in 1968 when WEUP sought inauguration of a nighttime service, it was unable to satisfy the coverage rules.
Though conceding this inability, WEUP asserts that the refusal to waive the rules is markedly inconsistent with the Commission’s disposition of cognate problems in earlier cases. In Great Southern Broadcasting Company, 19 the Commission dealt with an application for a permit to construct a new AM broadcasting station in Donelson, Tennessee, a small unincorporated community in Davidson County six miles east of Nashville. Nashville and Davidson County had recently merged to become a governmental complex of approximately 625 square miles, within the corporate limits of which were numerous communities, some with assigned radio stations, as well as rural areas. The Commission announced that “[s]ince the new municipality is so large and since it encompasses urbаn areas, small towns and farmland— all with diverse needs and interests — ... in allocating stations, [it would] continue to recognize the former town and city limits as they existed prior to the merger.” 20
Even earlier, in KDEF Broadcasting Company, 21 the Commission had adopted much the same approach. An Albuquer *1060 que, New Mexico, station broadcasting daytime-only was authorized to do so un-limitedly despite nonconformity with the 5 mv/m minimum field intensity rule. The station’s 5 mv/m coverage extended to only 67.8% of the area within the city limits of Albuquerque, though to 90.6% of its population, because large unserved areas within these boundaries were underpopulated. The Commission, concluding that waiver of the rule was called for, declared that “[i]t would be unduly harsh to require an applicant to render ‘principal city’ service to vacant acreage merely because the city — even though with an eye toward future development — has laid out its boundaries so as to encompаss such acreage.” 22
Hitherto, we have had occasion to deal with claims of disparate decisional treatment accorded parties by administrative bodies. Speaking of one agency, we have twice said that it “cannot act arbitrarily nor can it treat similar situations in dissimilar ways,” 23 and we remanded litigation to the agency when it did not take pains to reconcile an apparent difference in the treatment accоrded litigants circumstanced alike. 24 We have pursued the same course with respect to the agency now before us where “the differences [were] not so ‘obvious’ as to remove the need for explanation.” 25 These rulings vividly reflect the underlying principle that agency action cannot stand when it is “so inconsistent with its precedents as to constitute arbitrary treatment amounting to an abuse of discretion.” 26
The Commission’s counsel argue that there was no deviation from precedent in the case at bar, and they endeav- or to distinguish the earlier decisions to which we have adverted. It is clear, however, not only that “[m]ore than enumeration of factual differences between cases is required,” but also that “the Commission must explain their relevance to the purposes of the” legislation it administers. 27 Only recently we admonished that “[t]he premises upon which the validity of an administrative order is to be decided are only those upon which the agency predicated its action,” 28 for “[i]t is ‘a simple but fundamental rule of administrative law . . . that a reviewing court, in dealing with a determination or judgment which an administrative agency alone is authorized to make, must adjudge the propriety of such action solely by the grounds invoked by the agency.’ ” 29
Here the Review Board did not attempt to reconcile its disposition of WEUP’s application with рast decisional practice; although the problem was evi *1061 dent, the Board did not address it at all. 30 We cannot accept rationalizations offered by counsel as an adequate substitute for a response due the Commission itself. It is neither for counsel nor for us, but for the Commission itself, to explain any distinguishing characteristics it finds appealing, and to do so on a basis demonstrative of their pertinence to its statutory responsibilities.
Ill
WEUP’S licensee, Garrett Broadcasting Serviсe, is solely owned by appellant Leroy Garrett, who is black. The record indicates that, at least when the case was before the Commission, WEUP’s staff with minor exceptions was also black. WEUP was and is one of the infinitesimal number of black-owned and -operated broadcasting stations to be found anywhere in the United States. 31
Beyond that, 16,729 of Huntsville’s total population of 137,802 are black citizens, to whom WEUP can and does cater in its programing. 32 WEUP claims that its proposed nighttime service area would have embraced 111,812, of whom 15,394 are bla,ek, that it would also have brought primary AM service to 53,296, including 4,494 blacks, who receive such service from but one AM station, and to an additional 12,689, including 1,525 blacks, who have no AM .service at all. 33
At the administrative level, WEUP urged that its black ownership and black operation was a factor deserving careful attention. The administrative law judge did not even allude to that fаctor in his initial decision, and the Review Board dismissed it as “without decisional significance.” 34 Though advertent to WEUP’s claim that its nighttime proposal would provide service to the vast majority of Huntsville black inhabitants 35 the Board noted that it had “reviewed applicable precedent and” believed that “such precedent precludes a waiver under all the present circumstances.” 36 Without *1062 assigning any weight to the black-ownership black-operatiоn factor, 37 the Board declared that WEUP had “assumed a heavy burden in this case to overcome the gross inadequacy of coverage of Huntsville and” that “such burden has not been met.” 38
In this analysis and appraisal of WEUP’s contention, the Review Board was grievously incorrect. In our recent TV 9 decision 39 we addressed a situation wherein the Commission had refused to accord merit 40 to a contestant for a television channel by reason of the inclusion оf two black stockholders in its venture. The Review Board had held, and the Commission had agreed, that “[u]nless [the applicant] showed that the participation of [blacks] in the operation of the station would use their experience, background and knowledge of the community in a way likely to result in a superior service it cannot prevail on this point”; 41 and that “[t]here is nothing in the degree or type of participation proposed . which gives assurance that the benefits of their racial background will inure in any material degree to the operation of the station.” 42 The Board had further expressed the belief “that, in a comparative broadcast proceeding, . Black ownership cannot and should not be an independent comparative factor,” 43 but “rather . . . must be shown on the record to result in some public interest benefit,” 44 and “is deei-sionally significant only when reflected in active participation in station affairs.” 45
We rejected these arguments; we stated:
[Mjinority stock ownership of an applicant serving [] community is a consideration relevant to a choice among applicants of broader community representation and practicable service to the public. The credit awarded due to . participation, as a part own *1063 er, in management is not the same as credit based on broader community representatiоn attributed to [black] ownership and participation. 46
Consequently, we held “that when minority ownership is likely to increase diversity of content, especially of opinion and viewpoint, merit should be awarded,” 47 and that “[Reasonable expectation, not advance demonstration, is a basis for merit to be accorded relevant factors.” 48
It is evident that the Review Board’s treatment of WEUP’s blackness cannot be harmonized with the principles articulated in TV 9. The Board gave that factor no weight whatsoever because WEUP did not undertake to demonstrate independently that its black-oriented programming would surpass that of older area stations. 49 The entire thrust of TV 9 is that black ownership and participation together are themselves likely to bring about programming that is responsive to the needs of the black citizenry, 50 and that that “reasonable expectation,” without “advance demonstration,” gives them relevance. 51 We think it clear that WEUP’s long and solid identification with black listeners in Huntsville gained pertinence when the effort to enlarge its audience was made. 52
In sum, it is incumbent upon the Commission to reevaluate its determination on applicability of its coverage rule in light of its past precedents, 53 and, if necessary, its conclusion on waiver in light of TV 9. 54 To these ends, we remand this case to the Commission for further proceedings in conformity with this opinion.
So ordered.
Notes
. Garrett Broadcasting Service is a sole proprietorship owned by appellant Leroy Garrett. See Part III, infra.
. Leroy Garrett, No. 19258 (June 17, 1971). The Commission explained that “[t]he applications are mutually exclusive in that a grant of the [WEUP] application would raise WRBN’s RSS nighttime limitation (above that received from existing stations) to such an extent that it would fail to cover a substantial portion of Warner Robins.” Id.
. See text infra at notes 9-11.
. Leroy Garrett,
. The administrative law judge said:
WRBN would operate from a transmitter site within the corporate city limits of Warnеr Robins in the northwest sector some 2 miles from the center of the city. If granted alone, the proposed 11.26 mv/m contour would encompass 92.4% of the population and 89.4% of the area of the city of Warner Robins. If granted simultaneously with the [WEUP] proposal, the proposed 14.54 mv/m contour would encompass 81.4% of the population and 77% of the area of the city. The present transmitter site is considered near to being optimum for coverаge of the city. In view of the fact that the WRBN proposal would provide the second nighttime aural transmission outlet and the first nighttime competitive voice in Warner Robins, it is concluded that, with 92.4% coverage of the city population, a waiver of [the coverage rules] is warranted.
Id, at 125 (citations omitted).
. The Review Board said:
The first question involves Garrett’s contention that the public interest requires that Rule 73.30(c) be waived because its proposal would provide a first AM primary service to 12,689 persons in Huntsville and Madison and the maximum number of AM services within the proposed service area is three. The Board does not believe that these factors warrant waiver for the following reasons: First, the grossly inadequate coverage leaves unserved over one-fourth of the population and one-half of the area of Huntsville — the city of license. Second, as noted by the Presiding Judge, the minimum number of combined aural (AM and FM) receрtion services within the total proposed service area of Garrett is three; moreover, even this situation occurs in an area where only 159 persons are involved. The maximum number of combined aural services is eight. In this regard, it is important to note that in recent Commission pronouncements there is an emphasis of treatment of AM and FM as a single aural service in evaluating unserved or underserved areas. Cf. Report and Order in Docket No. 19074,32 FCC 2d 937 (1972) at paras. 12 and 20. In Cherokee Broadcasting Co.,17 FCC 2d 121 at 123, 15 RR 2d 1205 at 1208 (1969), a proceeding invоlving an applicant for an FM license and a Section 307(b) issue, the Commission stated that “our long-term goal must be the establishment of an integrated AM-FM aural service and we should look to the day when AM and FM stations can be regarded as component parts of a total aural service.” See also, Report and Order in Docket No. 15084, 2 RR 2d 1658 (1964), and Babcom Inc.,24 FCC 2d 690 , 19 RR 2d 883 (1970) petition for reconsideration denied,27 FCC 2d 437 , 21 RR 2d 6 (1971). Finally, if the Garrett proposal were granted, it would reduce the nighttime coverage in the сity of Warner Robins by the WRBN proposal from 92.4% to 81.4% of the population of that city. .
The Commission has long held that an applicant proposing to operate in a manner which results in a substantial violation of its technical rules assumes a heavy burden to establish that a grant of its application is in the public interest. Here, there can be no question that (a) the proposal’s grossly inadequate coverage of the city of Huntsville is a public interest detriment and results in a grossly inefficient use of this frequency at night; (b) there has been no concomitant showing of sufficient public interest benefits which outweigh this detriment; and (c) such lack of coverage to the city of license is not justified for the purpose of establishing a sixth Huntsville nighttime aural transmission outlet, or a fourth nighttime AM transmission outlet. Nor has the Huntsville applicant established, on the basis of this record, that any portion of its proposed servicе area is an underserved aural reception radio area. . Under these circumstances, we find the applicant’s argument that it is, in effect, penalized here because Huntsville is a large, irregular shaped, city caused by annexations and marked expansion resulting from the phenomenon of enormous urban expansion particularly during recent years, wholly lacking in merit. Moreover, the fact that Huntsville existing stations do not now cover the entire city in no way justifies the addition of a new substandard proposal, and this fact can be accorded no significant weight in our determination of the waiver question here. In sum, we believe Garrett assumed a heavy burden of proof in this case to overcome the gross inadequacy of coverage of Huntsville and, in our view, such burden has not been met.
Leroy Garrett,
. Leroy Garrett,
. Pursuant to 47 U.S.C. § 402(b)(1) (1970).
. 47 C.F.R. § 73.30(c) (1972). This provision was deleted in the process of amendment of the Commission’s rules in 1973. 38 Fed.Reg. 5874 (1973). The amendments, however, apply only to applications filed after April 10, 1973, the date upon which they went into effect. Id.
. 47 C.F.R. § 73.188(b)(2) (1973).
. Leroy Garrett,
supra
note 4,
. Id. at 124-125.
. Leroy Garrett,
supra
note 6,
. See note 7, supra.
. Parts II, III, infra.
. See Leroy Garrett, supra note 7, 41 F.C. C.2d at 619 (Comm’n) (dissenting statement).
. See Leroy Garrett, supra note 4, 38 F.C. C.2d at 120 (initial decision).
. Id.
.
.
Id. See also
Central Broadcasting Co.,
.
. Id. at 636 (footnote omitted).
. Herbert Harvey, Inc. v. NLRB, 137 U.S.App. D.C. 282, 292,
. Herbert Harvey, Inc. v. NLRB,
supra
note 23,
. Melody Music, Inc. v. FCC, 120 U.S.App. D.C. 241, 243-244,
. Herbert Harvey, Inc. v. NLRB,
supra
note 23,
. Burinskas v. NLRB,
supra
note 23, 123 U.S. App.D.C. at 148 n. 5,
. Tygrett v. Washington, Nо. 72-1876 (D.C. Cir. Oct. 23, 1974), at 13. See also the cases there cited.
.
Id.,
quoting SEC v. Chenery Corp.,
. As we have stated, the Commission refused to review the decision of the Review Board, see text
supra
at note 7, although Commissioner Hooks, in dissent, espoused the view that WEUP’s application should have been considered in light of
Great Southern,
see text
supra
at notes 19-20. Leroy Garrett,
supra
note 7,
. “In 1973, there were over 7,000 radio stations and 1,000 television stations operating in the United States. Of these, only 33 radio stations located in 20 States and the District of Columbia and no televisiоns stations were owned by minority group members.” U. S. Comm’n on Civil Rights, the Federal Civil Rights Enforcement Effort — 1974, vol. I at 49 (1974) (footnote omitted).
. Leroy Garrett,
supra
note 4,
. These data were presented to the Commission. There are no findings with reference to them.
. Leroy Garrett,
supra
note 6,
. Id. at 113.
. More fully, the Board said:
The second question relates to Garrett’s claim that (a) 85% of the blacks in the city will be served by his operation; and (b) there is presently “widespread dissatisfaction” with black oriented radio. The Board has reviewed the applicable precedent and, in our view, such precedent precludes a waiver under all the present circumstances. Initially, it is to be noted that the record in this proceeding is practically totally barren of any showing of the claimed “dissatisfaction” and that nowhere has Garrett indicated any specifics of what is wrong with existing programming or what he would do to improve the situation if his request for a change in facilities were granted. In addition, this record is barren of evidence that the black рopulation of Huntsville do not have FM receivers and, hence, are under-served from that standpoint. Moreover, the Commission has recently had occasion to consider similar arguments in cases involving questions of waiver of other technical rules. In Mel-Lin, Inc.,22 FCC 2d 165 , 18 RR 2d 787 (1970), the Commission, after agreeing with the Review Board that the applicant had “made commendable efforts to ascertain and propose programs designed to serve the needs of . [the minority population] on a continuing basis . . . ,” reversed the Review Board’s grant of the application. The Commission suggested that “representatives of concerned organizations might properly contact the existing fulltime stations ... to see if greater efforts can be made to establish more meaningful communications with the [black] audience.” *1062 In a later case, Champaign National Bank,22 FCC 2d 790 at 792, 18 RR 2d 1170 at 1174 (1970), the Commission, after denying a request for waiver of Section 73.24(b)(3) of the Rules, stated thаt “[a]ttempts to cure programming deficiencies by distorting or ignoring sound allocation and station assignment principles would constitute acts of expediency running counter to our statutory mandate to make the most effective use of the crowded AM band on a national basis.” See also, 1360 Broadcasting Co., Inc.,36 FCC 1478 , 2 RR 2d 824 (1964), where a request for waiver of the 10% rule based upon the special needs of the black audience was denied, and a similаr holding in Grantell Broadcasting Co.,23 FCC 2d 74 , 18 RR 2d 1063 (1970).
Id. at 113-115 (emphasis supplied).
. See id. at 114, 115, quoted supra notes 6, 36.
. Id. at 115, quoted supra note 6.
.
. In our supplemental opinion in
TV 9,
.
Id.
at 356,
. TV 9, Inc. v. FCC,
supra
note 39, 161 U.S. App.D.C. at 356,
. TV 9, Inc. v. FCC,
supra
note 39, 161 U.S. App.D.C. at 356,
. TV 9, Inc. v. FCC,
supra
note 39, 161 U:S. App.D.C. at 356,
. TV 9, Inc. v. FCC,
supra
note 39, 161 U.S. App.D.C. at 356,
. TV 9, Inc. v. FCC,
supra
note 39, 161 U.S. App.D.C. at 357,
.
Id.
at 358,
.
Id. See also
Citizens Communications Center v. FCC,
. Leroy Garrett,
supra
note 6,
.
See
TV 9, Inc. v. FCC,
supra
note 39,
.
Id.
at 358,
. We are mindful that the issue in
TV 9
arose in a contest for a station license while the context here is allocation of the AM band, but that in our view summons no difference in principle. The ultimate concern in each instance is the public interest, see, e.
g.,
47 U.S.C. §§ 307(a), (d), 309(a), 316(a) (1970); TV 9, Inc. v. FCC,
supra
note 39, 161 U.S.App. D.C. at 356-357, 361-362,
. See Part II, supra.
. See this Part III, supra.