End users of conventional or trunked Specialized Mobile Radio systems that have control stations that require FAA clearance, as specified in Sec. Sec. 17.7 through 17.17 of this chapter, or that may have a significant environmental effect, as defined by Sec. 1.1307, or that are located in a ``quiet zone'', as defined by Sec. 1.924 of this chapter must be individually licensed for such control stations prior to construction or operation. All other end users' operations will be within the scope of the base station licensee. All end users, however, continue to be responsible to comply with 47 CFR part 90 and other federal laws. [57 FR 40850, Sept. 8, 1992, as amended at 63 FR 68970, Dec. 14, 1998]