The symbols and their meanings for station operations. Note: These all apply to the NRC AM LOG. D1 Day time (sunrise to sunset) operation only, nondirectional antenna. D3 Day time operation only, directional antenna, same pattern at all times. D4 Day time operation only, directional during Critical Hours (CH) (sunrise to two hours after sunrise and two hours before sunset to sunset) only. D5 Day time operation only, directional during non-critical hours, non-directional during critical hours. D6 Day time operation only, different patterns during critical hours and non-critical hours. L1 Limited time operation (usually based upon sunrise or sunset at the dominant station's location on a clear channel), non-directional. L3 Limited time operation, directional antenna. N1 Night time (sunset to sunrise) operation only, non-directional. N2 Night time (sunset to sunrise) operation only, directional. SH Specified hours, as directed by the station license. Numbers showing pattern correspond to numbers under "U" category. Specified hour stations are those who would normally be unlimited but because of financial or other considerations, have petitioned for a waiver of the minimum schedule of 0600-2200 local time. ST Shared time operation; broadcasting time shared with a second station on the same channel (or in one case, three station share time). Numbers same as under "U" category. U1 Unlimited time operation, with non-directional antenna. U2 Unlimited time operation. directional at night (sunset to sunrise) only. U3 Unlimited time operation, directional all hours, same pattern day and night. U4 Unlimited time operation, directional, different patterns day and night. U5 Unlimited time operation, directional day, non-directional night. U6 Unlimited time operation, directional night and critical hours, same pattern. U7 Unlimited time operation, directional all hours, but three different patterns (day, night and critical hours). U8 Unlimited time operation, directional critical hours and night(different patterns), non-directional day. U9 Unlimited time operation, directional non-critical day hours and nights (different patterns) but non-directional during critical hours. U10 Non-Directional Day, Directional; Critical Hours, Non-Directional Nights Other terms // : running parallel 00 : on the hour AC : adult contemporary AP : associated press AP : application petition AMS : am stereo AOR : album oriented rock BBD : big band C&W : country and western CCR : contemporary christian radio CH : critical hours CHR : contemporary hit radio CID : code ID CL : call letters CLA : classical CP : construction permit C-QUAM : motorola am stereo EZL : easy listening EE : english FF : french GOS : gospel IBOC : in band on channel digital JJ : japanese LSR : local sun rise LSS : local sunset NBA : national basketball association NFL : national football league NHL : national hockey league NPR : national public radio OC : open carrier PSRA : pre sun rise authorization PSSA : post sun set authorization QRM : man made electrical noise QRN : natural electrical noise [ lightning etc.. ] QTH : location PRI : public radio international REL : religious ROK : rock RS : regular schedule RX : receiver $ : stereo SID : singing id SRS : sun rise skip SSS : sun set skip SS : spanish SSB : star spangled banner STA : special operations authorization SX : synchronous authorization TC : time check TOH ID : top of the hour id. TT : test tones TX : transmitter UC : urban contemporary UPI united press international VID : voice ID XMTR : transmitter XLATOR : translator