Before the FEDERAL COMMUNICATIONS COMMISSION FCC 95-253 Washington, D.C. In the Matter of ) RuralVision Central, Inc. and ) RuralVision South, Inc. ) 12 Applications for Authority to ) Construct and Operate Multipoint ) Distribution Service Stations on the ) H Channels at Five Transmitter Sites ) MEMORANDUM OPINION AND ORDER ON RECONSIDERATION Adopted: June 15, 1995 Released: July 7, 1995 By the Commission: I. INTRODUCTION 1. The Commission has before it petitions for reconsideration of the return, pursuant to delegated authority, of 12 applications for authority to construct and operate Multipoint Distribution Service ("MDS") stations on the H channels at the following five transmitter sites: Powers Crossroads, Georgia; Lakenan, Missouri; Lykens, Ohio; Muskogee, Oklahoma; and Salem, Oregon. These applications were filed with the Commission by RuralVision Central, Inc. and RuralVision South, Inc. between January 2, 1992 and March 26, 1992. As these petitions raise common issues, we believe that their collective consideration is the most efficient use of Commission resources. Thus, we will consider these petitions for reconsideration in this single order, which has been referred by the staff to the Commission pursuant to  1.106(a) of the Commission's rules, 47 C.F.R.  1.106(a). II. BACKGROUND 2. In order to implement the reallocation of the three H channels from the Private Operational-Fixed Microwave Service ("OFS") to the Multipoint Distribution Service, the Commission placed a freeze on the filing of such applications pursuant to Part 94 of the Commission's rules starting September 27, 1991, and ending January 2, 1992. Amendment of Parts 21, 48, 74, 78, and 94 of the Commission's Rules Governing Use of the Frequencies in the 2.1 and 2.5 GHz Bands Affecting: Private Operational-Fixed Microwave Service, Multipoint Distribution Service, Multichannel Multipoint Distribution Service, Instructional Television Fixed Service, and Cable Television Relay Service, Second Report and Order, 6 FCC Rcd 6792, 6794, n.9 (1991) (hereinafter Second Report and Order). As of January 2, 1992, the date the first of the above-captioned applications was filed, Part 21 of the Commission's rules applied to H channel applications and authorizations. 3. Section 21.20(a) of the rules sets forth the standards for returning MDS applications as unacceptable for filing: Unless the Commission shall otherwise permit, an application will be unacceptable for filing and will be returned to the applicant with a brief statement as to the omissions or discrepancies if: (1) The application is defective with respect to completeness of answers to questions, informational showings, execution, or other matters of a formal character; or (2) The application does not substantially comply with the Commission's rules, regulations, specific requests for additional information, or other requirements. 47 C.F.R.  21.20(a). 4. Mutual Exclusivity. Typically, the first determination made by Commission staff is whether an MDS application is mutually exclusive with any previously filed application or authorized station. Section 21.31(a) of the Commission's rules provides the standard for this determination. The Commission will consider applications to be mutually exclusive if their conflicts are such that the grant of one application would effectively preclude by reason of harmful electrical interference, or other practical reason, the grant of one or more of the other applications. The Commission will presume "harmful electrical interference" to mean interference which would result in a material impairment to service rendered to the public despite full cooperation in good faith by all applicants or parties to achieve reasonable technical adjustments which would avoid electrical conflict. 47 C.F.R.  21.31(a); see 47 C.F.R.  21.902(c), (d), and (f). In applying this standard, the staff evaluates whether the MDS applications were filed: (1) within 50 miles of an authorized or previously proposed MDS station and (2) within the radio horizon, with an unobstructed electrical path to the protected service area of an authorized or previously proposed MDS station. In the Matter of 4,330 Applications for Authority to Construct and Operate Multipoint Distribution Service Stations at 62 Transmitter Sites, 10 FCC Rcd 1335, 1340, nn.5, 6 (1994). Applications which are determined to be either within 50 miles or with an unobstructed electrical path to any part of the protected service area of any station are considered to be mutually exclusive with the station unless they demonstrate a lack of harmful interference by submitssion of interference studies with their application, pursuant to the standards specified in the Commission's rules. See 47 C.F.R.  21.902(b)(3) and  6, infra. 5. Cut-Off Rules. In order to be acceptable for filing MDS applications must be filed on or before the applicable cut-off date for mutually exclusive applications. Because the above-mentioned applications were filed after October 31, 1990, if they are mutually exclusive with a previously proposed application or an authorized station, the applicable cut- off rule is  21.914, which provides that: Notwithstanding the provisions of  21.31(b)(i) and (ii) of this part, to be entitled to a random selection process or to comparative consideration with one or more conflicting applications, an application . . . must be received by the Commission in a condition acceptable for filing on the same calendar day as the first of the conflicting applications is received by the Commission in a condition acceptable for filing. 47 C.F.R.  21.914. 6. MDS Interference Studies. At the time the above-referenced applications were filed section 21.902(b)(3) required each MDS applicant to engineer its proposed station to provide at least 45 dB of interference protection within the protected service areas of all other authorized or previously proposed cochannel stations. 47 C.F.R.  21.902(b)(3). In order to demonstrate compliance with this condition for use of an MDS frequency and so that mutually exclusive determinations could be made,  21.902(c)(1) of the Commission's rules required that an MDS applicant include with the application an analysis of the potential for harmful cochannel interference with any authorized or previously proposed station if the applicant's proposed transmitting antenna had an unobstructed electrical path to any part of the protected service area of any other authorized or previously proposed cochannel station or if the applicant's proposed transmitter was within 50 miles of the transmitter coordinates of any other authorized or previously proposed cochannel station. 47 C.F.R.  21.902(c)(1)(1991). In addition, the applicant must show what steps it has taken to comply with the requirements of  21.902(a), which requires, inter alia, MDS applicants, licensees, and conditional licensees, to make exceptional efforts to avoid harmful interference with other users and to avoid blocking potential cochannel stations in nearby areas. 47 C.F.R.  21.902(a). 7. ITFS Interference Studies. On reconsideration, the Commission staff did not evaluate the ITFS interference analyses submitted by applicants because none of the H channel applications had been placed on public notice and the ITFS studies are not due to be filed with the Commission or served on affected ITFS licensees until an H channel application has been placed on public notice. III. PETITIONS FOR RECONSIDERATION 8. The Commission staff returned each of the above referenced H channel applications as defective and unacceptable for filing by individual return notification letters. Each of the letters indicated that the applications were returned because the applicants: (1) filed past the cut-off period established in  21.31 or  21.914; (2) filed in area not open for filing, pursuant to  21.901(d)(4) as the applications did not meet the criteria established in Public Notice, Common Carrier Bureau Opens Filing Period for Multichannel Multipoint Distribution Service Applications, 3 FCC Rcd 2661 (1988) (hereinafter 1988 Public Notice); and/or (3) failed to meet the requirements for performance of interference studies as required by  21.902 due to failure to serve all affected parties with interference studies and failure to consider all authorized or previously proposed MDS stations. A description of the applications filed for each of these locations, the reasons for the staff's disposition of each application, and the arguments presented in the petitions follow. 9. Powers Crossroads, Georgia. On January 2, 1992, RuralVision South filed MDS applications for the H-1, H-2, and H-3 channels proposing the same transmitter site at Powers Crossroads, Georgia. The Powers Crossroads return notification letters were dated August 25, 1993, and reconsideration petitions for the returned applications were timely filed on September 24, 1993. 10. Petitioner contends that there was no cut-off date applicable to its applications. However, the cut-off date for the H-1 channel application was established by a mutually exclusive application filed on September 11, 1990, for Phenix City, Alabama; the cut-off date for the H-2 channel application was established by a mutually exclusive application filed on May 15, 1987, for Atlanta, Georgia; and the cut-off date for the H-3 channel application was established by a mutually exclusive application filed on March 27, 1989, for Atlanta, Georgia. These mutually exclusive applications were filed approximately one to four years prior to petitioner's filings. The Powers Crossroads applications, each of which was filed after October 31, 1990, were mutually exclusive, pursuant to  21.31, and cut-off, pursuant to  21.914, in that they were not received by the Commission in a condition acceptable for filing on the same calendar day as the first of the conflicting applications were received by the Commission in a condition acceptable for filing. 47 C.F.R.  21.31, 21.914. 11. The Powers Crossroads H-1, H-2 and H-3 channel applications proposed a transmitter site within 50 miles or the radio horizon of (1) previously authorized stations at Atlanta, Georgia and Phenix City, Alabama and (2) previously proposed cochannel stations at Carrollton, Georgia and Griffin, Georgia with applications pending on January 2, 1992, the filing date of the Powers Crossroads applications. Each application lacked interference studies, required by  21.902 (b) and (c), for the two previously proposed cochannel MDS stations. 12. The cochannel interference studies that were submitted with the applications were inadequate in that the applicant: (1) did not include free space calculations for the desired to undesired signal ratio to each reference receiving antenna within the protected service area of the authorized or previously proposed stations, as required by  21.902(c), (d) and (f) (see  21.902(e)); (2) indicated terrain blockage, but submitted inadequate terrain profiles; and (3) failed to engineer the stations to provide at least 45 dB of cochannel interference protection pursuant to  21.902(b)(3). 13. Lakenan, Missouri. On January 16, 1992, RuralVision Central filed MDS applications for the H-1, H-2, and H-3 channels proposing the same transmitter site at Lakenan, Missouri. The Lakenan return notification letters were dated August 25, 1993 and reconsideration petitions for the returned applications were timely filed on September 24, 1993. 14. Petitioner contends that there was no cut-off date applicable to its applications. However, the cut-off date for the H-1, H-2, and H-3 channels was established by mutually exclusive applications filed for Kirksville, Missouri on February 11, 1991. Thus the Lakenan applications were mutually exclusive, pursuant to  21.31, and cut-off, pursuant to  21.914, in that they were not received by the Commission in a condition acceptable for filing on the same calendar day as the first of the conflicting applications was received by the Commission in a condition acceptable for filing. 47 C.F.R.  21.31, 21.914. 15. The Lakenan H-1, H-2 and H-3 channel applications proposed a transmitter site within 50 miles or the radio horizon of (1) authorized stations at Kirksville, Missouri and Hannibal, Missouri and (2) previously proposed cochannel stations at Wyman, Iowa with applications pending on January 16, 1992, the filing date of the Lakenan applications. Each application lacked an interference study, required by  21.902 (b) and (c), for the previously proposed cochannel MDS stations. 16. The cochannel interference studies that were submitted with the applications were inadequate in that the applicants: (1) did not include free space calculations for the desired to undesired signal ratio to each reference receiving antenna within the protected service area of the authorized or previously proposed stations, as required by  21.902(c), (d) and (f) (see  21.902(e)); (2) indicated terrain blockage, but submitted inadequate terrain profiles; and (3) failed to engineer the stations to provide at least 45 dB of cochannel interference protection pursuant to  21.902(b)(3). 17. Lykens, Ohio. On January 30, 1992, RuralVision Central filed one H-2 channel MDS application proposing a transmitter site at Lykens, Ohio. The Lykens return notification letter was dated August 25, 1993, and a reconsideration petition for the returned application was timely filed on September 24, 1993. 18. The application proposed a transmitter site that was within the radio horizon and for which there was an unobstructed electrical path to the protected service area of previously authorized cochannel MDS station WNTH924 at Lima, Ohio, Application File No. 768310. The application lacked an interference study, required by  21.902(b) and (c), for the previously authorized cochannel MDS station. 19. Muskogee, Oklahoma. On January 16, 1992, RuralVision Central filed MDS applications for the H-1, H-2, and H-3 channels proposing the same transmitter site at Muskogee, Oklahoma. The Muskogee return notification letters were dated August 25, 1993, and reconsideration petitions for the returned applications were timely filed on September 24, 1993. 20. Petitioner asserts that it did not file its applications past any applicable cut-off date. However, the cut-off date for the H-1 channel was established by a mutually exclusive application filed on July 18, 1991, for Tulsa, Oklahoma; the cut-off date for the H-2 channel was established by a mutually exclusive application filed on November 5, 1990, for Van Buren, Arkansas; and the cut-off date for the H-3 channel was established by a mutually exclusive application filed on November 5, 1990, for Van Buren, Arkansas. These mutually exclusive applications were filed approximately six to fourteen months prior to petitioner's filings. The Muskogee applications were mutually exclusive, pursuant to  21.31, and cut-off, pursuant to  21.914, in that they were not received by the Commission in a condition acceptable for filing on the same calendar day as the first of the conflicting applications was received by the Commission in a condition acceptable for filing. 47 C.F.R.  21.31, 21.914. 21. The Muskogee H-1, H-2 and H-3 channel applications proposed a transmitter site within 50 miles or the radio horizon of (1) authorized stations at Tulsa, Oklahoma, McAlester, Oklahoma, and Van Buren, Arkansas and (2) previously proposed cochannel stations at Canadian, Oklahoma with applications pending on January 16, 1992, the filing date of the Muskogee applications. Each application lacked interference studies, as required by  21.902 (b) and (c), for previously authorized MDS stations and a previously proposed cochannel MDS station. 22. The cochannel interference studies that were submitted with the applications were inadequate in that the applicant: (1) did not include free space calculations for the desired to undesired signal ratio to each reference receiving antenna within the protected service area of the authorized or previously proposed stations, as required by  21.902(c), (d) and (f) (see  21.902(e)); (2) indicated terrain blockage, but did not submit required demonstrations, such as shadow maps or terrain profiles; and (3) failed to engineer the stations to provide at least 45 dB of cochannel interference protection pursuant to  21.902(b)(3). 23. Salem, Oregon. On March 26, 1992, RuralVision Central filed MDS applications for the H-1 and H-2 channels proposing the same transmitter site at Salem, Oregon. The Salem return notification letters were dated August 25, 1993, and reconsideration petitions for the returned applications were timely filed on September 24, 1993. 24. Petitioner contends that it did not file its applications past any applicable cut-off date. However, the cut-off date for the H-1 channel application was established by a mutually exclusive application filed on February 14, 1990, at Newport, Oregon and the cut- off date for the H-2 channel application was established by a mutually exclusive application filed on April 12, 1990, at Newport, Oregon. These mutually exclusive applications were filed approximately two years prior to petitioner's filings. The Salem applications were mutually exclusive, pursuant to  21.31, and cut-off, pursuant to  21.914, in that they were not received by the Commission in a condition acceptable for filing on the same calendar day as the first of the conflicting applications was received by the Commission in a condition acceptable for filing. 47 C.F.R.  21.31, 21.914. 25. The H-1 and H-2 channel applications proposed a transmitter site that was within 50 miles or the radio horizon of (1) previously authorized cochannel MDS stations at Newport, Oregon and (2) previously proposed cochannel MDS stations at Portland Oregon, which had applications pending on March 26, 1992, the filing date of the Salem applications. 26. The cochannel interference studies that were submitted with the applications were inadequate in that the applicant: (1) did not include free space calculations for the desired to undesired signal ratio to each reference receiving antenna within the protected service area of the authorized or previously proposed stations, as required by  21.902(c), (d) and (f) (see  21.902(e)); (2) indicated terrain blockage, but did not submit required demonstrations, such as shadow maps or terrain profiles; and (3) failed to engineer the stations to provide at least 45 dB of cochannel interference protection pursuant to  21.902(b)(3). IV. DISCUSSION 27. Mutual Exclusivity and Cut-off. Based upon our review of the returned applications and publicly available information regarding authorized MDS stations and pending applications, we conclude that the petitioned applications were mutually exclusive with and cut-off by authorized stations or previously filed applications. The determining factors we used to ascertain if the above-referenced MDS applications were mutually exclusive pursuant to  21.31(a) were whether the applications were filed: (1) within 50 miles of an authorized or previously proposed MDS station or (2) within the radio horizon with an unobstructed electrical path to the protected service area of an authorized or previously proposed MDS station. Each of these returned applications proposed a transmitter site which made the proposed stations mutually exclusive, pursuant to  21.31, with authorized or previously proposed MDS stations. See  10, 14, 20, and 24, supra. Specifically, these returned applications were mutually exclusive with and cut-off, pursuant to  21.914, with respect to an authorized station, which had a cut-off date prior to the filing date of the returned applications. Thus, the above-referenced applications were properly returned as unacceptable for filing pursuant to  21.31(d), which states: An application otherwise mutually exclusive with one [or] more previously filed applications, but filed after the appropriate date prescribed in paragraph (b)(2) of this section, will be returned without prejudice and will be eligible for refiling only after final action is taken by the Commission with respect to the previously filed application (or applications). 47 C.F.R.  21.31(d). 28. We reject petitioners' contentions that their proposed stations were not cut-off because there were no previously proposed stations for the same service area proposed in their applications and their applications demonstrated interference protection to stations in nearby areas. Whether an MDS application is cut-off is not determined solely by the date of filing vis-a-vis applications specifying the same transmitter site or proposing service to the same town, but also by whether, pursuant to  21.31, granting the application would result in harmful interference to any authorized station for which the cut-off date is past. As explained above, the referenced returned applications were cut-off by mutually exclusive authorized stations which, although they specified cities different than the cities specified by the returned applications, would have received harmful interference from the stations proposed in the returned applications. See  10, 14, 20 and 24, supra. 29. Interference Protection. We find that the above referenced applications were also properly returned for failure to comply with the interference protection requirements of  21.902. At the very inception of MDS, the Commission established the principle that subsequently filed applications must not cause harmful interference to any previously proposed or authorized MDS station. "Of course, the applicant for the second channel sought will be expected to demonstrate that his system is designed so that significant interference will not occur with respect to the first MDS channel. . . ." MDS Allocation Order, 45 FCC 2d at 621. Eleven years before the above-referenced applications were filed, the Commission explained its emphasis on this requirement for MDS applications: It is possible for co-channel interference generated by one MDS station to cause unacceptable distortion of another station's signal from as far away as 50 miles. Section 21.90[2](c) of our Rules therefore requires an MDS application to include an interference study containing an analysis of the potential for harmful interference with other MDS stations located within a 50 mile radius of the proposed station. R.L. Mohr, 85 FCC 2d 596, 606 (1981). It has also been recognized that "the demonstration of interference protection, at the time of filing, aids the Commission in the public interest determination that an applicant is technically qualified to be an MDS/MMDS licensee." Family Entertainment Network, Inc., 9 FCC Rcd 566, 567-68, n. 10 (Dom. Fac. Div. 1994). Thus,  21.902(b) requires all MDS applicants and licensees to provide 45 dB of cochannel interference protection and to demonstrate that protection in interference studies submitted with the applications. 30. Petitioners' applications failed to demonstrate a lack of harmful interference to existing and previously proposed MDS stations. As discussed in  6, supra, applicants for new MDS stations on the H channels are required to file specific technical interference protection showings for cochannel stations at the time of filing. The interference analysis requirement is an imperative one which demands complete compliance at the time an application is filed for a proposed MDS site. Thus, the Commission stressed that "we expect applicants to address this problem in their applications. Those applications that do not contain an analysis of how the applicant intends to avoid cochannel interference in adjacent areas will not be considered acceptable for filing." Amendments of Parts 2, 21, 74 and 94 of the Commission's Rules and Regulations in regard to frequency allocation to the Instructional Television Fixed Service, the Multipoint Distribution Service, and the Private Operational Fixed Microwave Service, 94 FCC 2d 1203, 1264 (1983)(hereinafter MMDS Allocation Order); see also  21.902(b) and (c). Interference studies are necessary at the time of filing in order for determinations of mutual exclusivity to be made. Without them a logjam would be created, making it more difficult to reach final actions. 31. On reconsideration, petitioners assert that their consulting engineers studied the potential for interference for all previously proposed and authorized cochannel MDS stations and applications within 50 miles of or with an unobstructed electrical path from its proposed H channel stations which appeared on a specified private company's data base. Petitioners describe this particular company as "the most widely-used and reliable industry database" but acknowledge that certain applications were not in that commercial data base. Petitioners cite Central Mobile Radio Phone Service, 41 RR 2d 431 (1977) for their proposition that RuralVision "cannot be held accountable for compliance with information that was simply beyond its ken. . . . [An] applicant [is] not under a duty to investigate [a] prior proposal for which full notice [was] not given." Central Mobile Radio Phone Service however, is not persuasive here. 32. In that decision, the Commission issued a public notice identifying an application as acceptable for filing, but omitted from the public notice the frequency for which the applicant had applied. Thereafter, a second applicant applied for the same frequency in the same town and argued that by failing to specify the frequency in the public notice, the Commission staff had deprived the applicant of fair notice that the frequency had previously been granted. Upon review the Commission agreed that the public notice in question was not sufficient to satisfy the statutory public notice requirements. The facts involved in the instant case, however, do not involve reliance on the accuracy or completeness of a Commission public notice, but rather of a private, commercial data base which omitted references to some previously proposed applications on file at the Commission. Therefore, this case is not applicable to petitioners' situations. Petitioners would have received notice of the pendency of other applications if they had consulted Commission sources. Applicants who chose to utilize non-official inventories of Commission filings are not relieved of their duty to review prior proposals because they utilized an incomplete non-Commission affiliated information resource. In Friendly Community Television Services, 7 FCC Rcd 7892 (Dom. Fac. Div. 1992) (hereinafter Friendly), it was noted: Friendly's reliance on its engineering firm is not a mitigating factor. "Parties are charged with knowledge of and are bound by statutes and regulations despite reliance to their detriment upon incorrect information received from third parties. Cf. Rosner v. Secretary of Health, Ed. and Welfare, 306 F.Supp 853 (S.D. Fla 1970). [Friendly] is ultimately responsible for his application and for ensuring that it conforms to Commission rules. See [Bruce M.] Schorsten, 2 FCC Rcd [4409,] . . . 5422 n.3 (Comm. Car. Bur. 1987)." Ronald F. Trinchitella, 4 FCC Rcd 6360 (1989); see Digital Paging Systems, Inc., 2 FCC Rcd 1523, 1524 (Comm. Car. Bur. 1987). Friendly, 7 FCC Rcd at 7893. Just as misplaced reliance was not the basis for reinstatement for the MMDS applicant in Friendly, it is not a basis for reinstatement for the RuralVision applicants. Applicants' choice of a particular private company's data base cannot be used to avoid the consequences of their failure to use the Commission's official on-line contractor. Line of Site, Inc., 8 FCC Rcd 3145, 3146 (Dom. Fac. Div. 1993). 33. The Commission has, over the years, identified in public notices the third party entities with which the Commission has contracted to provide the public with on-line access to the MDS database. See e.g. Public Notice, New Contractor for Online Public Access to Commission Data Bases, Mimeo No. 10511 (November 7, 1990). Because petitioners knowingly relied on a non-Commission affiliated data base, the fact that it was incomplete or inaccurate does not protect them on reconsideration. Had petitioners consulted the Private Radio Bureau weekly public notices, the Commission's official MDS on-line access contractor, and the Multipoint Distribution Service ("MDS") staff listings of authorized or pending applications in the MDS Public Reference room, the petitioners would have had access to the most accurate information. Thus, petitioners are incorrect in asserting that the Commission held them "accountable for compliance with information that was . . . beyond its ken." 34. For each of the transmitter sites, the RuralVision applications failed to include all of the required interference analyses for previously proposed MDS stations, and the submitted interference studies were inadequate. We note that in some instances, some of the previously-filed applications were filed shortly before the RuralVision applications. All of these previously filed applications, however, were listed on the FCC staff listings or were placed on public notice months before the above captioned applications were returned. After submitting their own applications, petitioners did not continue to monitor MDS application filings to ensure that their applications had considered all previously proposed applications. Since  21.23(a)(1) states that "any pending application may be amended as a matter of right" petitioners should have amended their applications by filing additional interference studies for cochannel stations when such information was not available at the time petitioners filed, but became available at a later date. See CNI Wireless, Inc., 9 FCC Rcd 2039, 2040 (Dom. Fac. Div. 1994) (petitioner was required to monitor and file interference studies for applications filed eight days prior to petitioner's application). All petitioners could have amended their pending applications, to include interference studies for these cochannel station applications, pursuant to  21.23(a)(1), but failed to do so. Hence, each of the above applications were properly returned for failure to comply with the requirements for performance of interference studies as required by  21.902 because they failed to consider all authorized or previously proposed MDS stations. 35. Our analysis of the interference studies that were submitted shows that the returned applications failed, inter alia, to provide at least 45 dB of cochannel interference protection as required by  21.902(b); to submit free space calculations of the desired to undesired signal ratios to each reference receiving antenna within the protected service area of the authorized or previously proposed stations as required by  21.902(f); and failed to demonstrate terrain blockage (see  21.902(d)). See Revision of Part 21 of The Commission's Rules, 2 FCC Rcd 5713, 5716-17 (1987) ("Coordination of MDS . . . systems . . . relies on accurate data about the interference environment.") Thus, these applications were properly returned as unacceptable for filing. MDS Technical Order, 98 FCC 2d at 93 ("An application that proposes cochannel or adjacent channel operation and does not contain a showing that the proposed operation will not cause harmful interference as described herein will not be accepted for filing."); see also Family Entertainment, 9 FCC Rcd at 567 ("[T]he filing of an interference analysis, which demonstrates lack of harmful interference, is considered a basic requirement in determining the acceptability of an application."); Dan S. Bagley, Jr., 7 FCC Rcd 4002, 4003 (Dom. Fac. Div. 1992) ("In the processing of MDS station applications, the interference analyses required by [ 21.902] are crucial.") 36. Notice to Affected Parties. In addition, each applicant failed to serve, as required by  21.902(g), all applicants, conditional licensees and licensees for stations required to be studied by  21.902(c), thus depriving affected parties of notice and an opportunity to be heard. In Edna Cornaggia, 8 FCC Rcd 5442, 5444 (Dom. Fac. Div. 1993), the return of a modification application was upheld for failure to comply with  21.902(g): The Commission makes provision for actual notice and an opportunity to be heard by parties in interest by requiring at Section 21.902(g) that microwave stations that might be affected by operation of an MDS station be served a copy of the required interference analysis for their station. Cornaggia admittedly failed to properly serve VisionAire with a copy of the interference analysis . . . . Due to this lack of service, the orderly process contemplated in the Commission's rulemaking order, in which the Commission staff resolves interference problems after oppositions are filed, was negated. Hence, each of the above referenced applications were properly returned as unacceptable for filing due to failure to comply with the service requirements of  21.902(g). 37. Curative Amendments/Disparate Treatment. Petitioners argue that the Commission should now allow them to file additional interference studies as curative amendments, after their applications have been returned by return notification letter. Petitioners state that "[i]n every other case to date, the FCC has given MDS applicants the opportunity to submit minor amendments to cure their applications." Petitioners assert that the Commission violated administrative due process by failing to treat RuralVision applicants similarly to other MDS applicants who were given the opportunity to file minor curative amendments. Lastly, petitioners argue that if the Commission seeks to prohibit applicants from filing minor, curative, amendments in the form of interference studies, it must provide notice of this change in the Commission's processing of MDS applications. 38. We note at the outset that only pending applications are amendable as a matter of right. Section 21.23(a)(1) provides that any pending application may be amended as a matter of right if the application has not been designated for the random selection process. 47 C.F.R.  21.23(a)(1). The RuralVision applications reviewed in this order have been returned by return notification letter and thus, by definition, are no longer pending. Therefore, they may not be amended as a matter of right. Although petitioners claim that they were not given an opportunity to file minor curative amendments of interference analyses, this assertion is incorrect. RuralVision Central and RuralVision South had ample opportunity to amend their applications by filing minor, curative amendments prior to their return by the Commission. Although Commission rules allow applicants to amend their applications prior to return or dismissal by the agency, such rules provide no opportunity for amendment after applications have been returned. Therefore, petitioners are inaccurate in stating that "the FCC has suddenly decided to prohibit applicants from filing, minor curative amendments." 39. Petitioners cite several instances where the Commission staff sent deficiency letters to applicants designated as tentative selectees following their participation in the random selection process, and allowed the tentative selectees to cure defects in their applications: Stephen Communications Inc., 8 FCC Rcd 355 (Dom. Fac. Div. 1993); T/V Communications Associates, 7 FCC Rcd 7647 (Dom. Fac. Div. 1992); Stephen C. Bailey, 7 FCC Rcd 7252 (Dom. Fac. Div. 1992); and Microwave Video Services, 7 FCC Rcd 7254 (Dom. Fac. Div. 1992). Petitioners apparently seek to equate their return notification letters with the deficiency letters sent to tentative selectees and argue that the Commission's refusal to permit them to file curative amendments in response to their return notification letters is a violation of administrative due process. However, returned applicants and tentative selectees are treated differently under Commission rules because returned applicants have been found unacceptable for filing by Commission staff, while tentative selectees have been found acceptable for filing prior to participation in a lottery. "[A]ll applications must be acceptable for filing in order to be included in a lottery." Second Report and Order, Amendments of Parts 2, 21, 74 and 94 of the Commission's Rules and Regulations in Regard to Frequency Allocation to the Instructional Television Fixed Service, and the Private Operational-Fixed Microwave Service, 57 RR 2d 943, 949 (1985) (hereinafter MMDS Lottery Order). Since tentative selectees have already been found acceptable for filing, only minor clarifications or additions should remain to be made to the applications. Hence, Commission staff may send deficiency letters to a tentative selectee to cure minor problems prior to grant of an application that was otherwise acceptable for filing. However, an application that has been adjudged unacceptable for filing is, by definition, defective and properly returned or dismissed by Commission staff. 40. The cited deficiency letters involved four applicants who filed their applications in 1983, participated in the random selection process, had been selected as tentative selectees for qualification review and were subsequently notified by Commission staff of deficiencies in their applications. The Commission staff provided an opportunity to cure such deficiencies by amendment within 30 days. The deficiencies referred to in one of the letters appear to be deficiencies which, under the rules applicable at the time the application was filed, did not render the application unacceptable for filing. In the other instances cited, the applications were unacceptable for filing but were nevertheless entered in their respective lotteries. After the applicants were chosen as tentative selectees, they were erroneously given an opportunity to amend their applications to the cure deficiencies which made them unacceptable for filing in contravention of the procedures established in the MMDS Lottery Order. However, the Commission is not bound by such staff errors. See, e.g., North Texas Media, Inc. v. FCC, 778 F.2d 28, 33 (D.C. Cir. 1985). ("The initial improvident grant of a [short-spacing] waiver . . . now described as an error, does not deprive the agency of authority to require future applicants to meet certain standards in order to obtain such a waiver."); Quinnipiac College, 8 FCC Rcd 6285, 6286 (1993); Walter P. Faber, 4 FCC Rcd 5492, 5493 (1989), recon. denied, 6 FCC Rcd 3601 (1991), aff'd mem., Faber v. FCC, 962 F.2d 1076 (D.C. Cir. 1992). Therefore, the fact that tentative selectees in the cited instances may have been improperly given the opportunity to cure deficiencies in applications, which should have been dismissed as unacceptable for filing, does not compel the Commission to allow petitioners to amend their applications after they have properly been returned as unacceptable for filing, pursuant to established Commission rules and procedures. 41. Notice of Change in Commission Policy. Petitioners also state that the Commission failed to provide prior notice of a purported change in Commission processing of MDS applications which applied a new, strict standard by which RuralVision applications were dismissed due to minor defects. We note that RuralVision's applications were defective and unacceptable for filing in that petitioners failed to include required interference studies, submitted incomplete interference analyses, and failed to serve certain affected parties with the necessary interference studies. Pursuant to  21.20(a)(1) an application is defined as unacceptable for filing if it is "defective with respect to . . . informational showings." Interference analyses are informational showings and Part 21 rules further state that "[a defective] application will be returned to the applicant with a brief statement as to the omissions or discrepancies." Section 21.20(a)(1). Furthermore, as discussed in  29-30, supra, missing or inadequate interference studies are not "minor defects." 42. Petitioners further contend that "RuralVision had no prior notice that, due to an unknown omission in the database used by most applicants, the FCC would not allow applicants, upon discovery of that omission, to cure that defect by filing minor amendments." Applicants for new MDS stations on the H channels are required to file specific technical interference protection showings for cochannel stations with their applications. Although previously filed cochannel H-channel stations sometimes did not appear on FCC listings until after petitioners filed their applications, petitioners did not take advantage of their opportunity to monitor application filings and amend their applications by filing additional interference studies for the cochannel stations before their applications were returned. See  34, supra. While petitioners seek to add additional interference analyses to their original applications by including such studies with their reconsideration petitions, the Commission is under no obligation to accept curative showings after an application has been returned or dismissed. There has been a series of cases denying attempts to submit such showings at that stage. See note 45, supra. Thus, these applicants may not amend their applications upon filing of reconsideration petitions and their applications should not be reinstated nunc pro tunc. 43. RuralVision applicants failed to file the necessary interference studies and thus were unacceptable for filing. Petitioners' applications were properly returned by return notification letters. Despite petitioners' allegations, no new, strict standard was applied to their applications, rather they were to held to the Part 21 rules which applied to H channel applications and authorizations as of January 2, 1992. All MDS applicants are charged with being familiar with Part 21 of the Commission's rules. Any applicant who "either ignores or fails to understand clear and valid rules of the Commission respecting the requirements of an application assumes the risk that the application will not be acceptable for filing." Ranger v. FCC, 294 F.2d 240, 242 (D.C. Cir. 1961); see also Donald E. Benson, 8 FCC Rcd 1872, 1873 (Dom. Fac. Div. 1993). 44. In view of all the foregoing considerations, we affirm the staff's return of the applications under consideration in this order. Reconsideration is not justified and reinstatement of the applications is not warranted. 45. Accordingly, IT IS ORDERED, that the reconsideration petitions filed by the above-referenced applicants, ARE HEREBY DENIED. 46. IT IS FURTHER ORDERED, that the staff of the Mass Media Bureau shall send copes of the decision to the authorized representatives by certified mail, return receipt requested. FEDERAL COMMUNICATIONS COMMISSION William F. Caton Acting Secretary