radio station sign radio station near colorado continuously official frequency time signals carrier frequencies time signals controlled local atomic primary standard boulder colorado gps common view observations time transfer methods operates similar radio station hawaii recorded announcements share frequencies uses male voice distinguish uses female voice recorded announcements general interest gps satellite status severe oceanic weather warnings shares site near radio station carrier time code voice band history launch oldest continuously operating radio station united_states going air washington approximately months launch station broadcast friday evening concerts signal heard kilometers washington december began broadcasting distributing code news reports signal heard kilometers washington news broadcasts ended april standard frequency signals end purpose shifted broadcasting standard frequency signals signals desperately needed broadcasters equipment limitations time meant broadcasters stay assigned frequencies testing began january frequencies broadcast frequency broadcasts officially began march frequencies accurate better tenths percent manually switched frequency invented greatly improved accuracy frequency broadcasts nearly shut signal cover eastern half united_states stations located minneapolis stanford_university slowly making redundant station impending announced saved flood protests citizens relied service later underwent upgrade directly controlled moved maryland broadcasts began year later station moved land maryland broadcasts added power increased time signals tone reports added broadcast june nearly destroyed fire november frequency equipment recovered station air reduced power november congress funded new station july built kilometres south location referred location changed maryland resumed normal broadcasts august time signals primary purpose today existence official time provided government entities ensure uniform time maintained united_states world time signals generated allow time keeping devices radio controlled automatically maintain accurate time need manual adjustment time signals commercial institutional interests accuracy essential time plays vital role daily operations include shipping transport technology research education military public safety telecommunications particular importance broadcasting commercial public private interests amateur radio operators provides public service making time information readily available hours monetary charge cost receiving equipment broadcasting second tied actual time june allowed use clock source time signals year later october broadcast code time announcements minutes voice announcements started january broadcast minutes frequencies broadcast alternating minutes time broadcasting broadcasts ended coded time code began testing permanent nasa time code audio tone sounding somewhat like repeated code described sounding like buzz saw july time code broadcast changed present normal radio heard recorded chart recorder moved present location near december enabling better reception signal continental united_states signed location years earlier april stopped local time site eastern time mountain time switched broadcasting mean time station switched utc broadcasts discontinued broadcast reinstated year april signal air experimental mode voice august equipment changes required announcer voice time soon switched voice morning host radio signals atomic time signals derive maintained time based nearby boulder colorado time based maryland predecessor previously maintained currently signal unique purpose track russian satellite craft onboard electronics failed professor knew entering upper atmosphere leaves wake small air air reflects stray radio signal earth strengthening signal surface seconds effect known figured left exhibit effect larger scale prediction correct signal noticeably strengthened lasting minute addition strengthening came direction time day agreed predictions paths information able draw complete timeline particular observed satellites fall unit instead spacecraft broke component parts moved closer earth sign small number radio stations west mississippi_river sign beginning sign stems station early locations maryland sign maintained federal government moved station colorado fact government station fall jurisdiction respect signs sign assigned time signal station known regulations time stations issued signs beginning broadcast format standard carrier frequencies carries additional information standard double follow regular pattern repeating minute coordinated sister station limit interference similar described date time date exact time follows english language voice announcements time coded time code date time transmitted varying length tone bit second cases transmitted time given coordinated universal time utc second minute markers audio second allow accurate manual clock transmitted voice announcements silent periods begins second lasts consists cycles wave stand signals suppressed second exception silent interval transmitted seconds past minute event leap second transmitted second minute minute extended second long followed silence hour minute pulse transmitted beginning tone corresponds start minute seconds sixteen inclusive past minute current difference utc transmitted doubling second second second silent zone absolute value difference tenths second determined number doubled sign determined position doubled begin second ahead utc begin second utc similar sent cycles minute hour minute tones transmitted voice time announcements voice announcements time day end minute giving time following minute format voice announcement tone hours minute announcement male voice begins seconds minute tone makes identical time announcement starting seconds minute tone female voice voice announcements instituted follows tone returns time eastern standard time switch utc announcement changed colorado tone begins hours minute mean time format short lived announcement changed current format voice time announcements sent carrier varies nominal power standard frequencies transmit seconds audio tone minutes begins second minute mark continues beginning time announcement seconds minute minutes minute transmit heard odd minutes tone interrupted second second similar exchanges tones minutes odd tone pitch commonly music note middle minute hour hour utc day tone transmitted hour chart use tone mark hour day likewise omission tone day mark hour period tone minute hour tone transmitted voice announcements causes transmit tone minutes inclusive minutes hour likewise tone minutes audio tones voice announcements sent voice announcements following second voice announcements lieu standard frequency tones hourly schedule station identification past hour marine storm warnings provided national_weather_service atlantic_ocean minutes past pacific_ocean past past gps satellite health reports past special alert report transmitted containing information solar activity radio propagation conditions particular discontinued september june announcing past decision retracted alert reports continue future additional time slots normally transmitted standard frequency tone voice messages necessary past hour broadcasts announcements manual change operation leap second announcements minutes marked broadcast schedule reserved tone broadcast minute additional storm warnings necessary tone transmitted information different schedule voice announcements timed avoid airs dead air airs voice announcements vice versa storm warnings cover area hawaiian islands far_east north_america digital time code time day continuously transmitted digital time code radio controlled time code uses main signal additional low level tone added audio signals code similar framework time code time code individual fields code rearranged transmitted significant bit sent like time transmitted time start minute like data minute hour day year year sent coded format simple digit sent bits depending possible range values bit transmitted beginning start second reserved seconds reduced times second duration high data bit data bit marker follows reduced past second indicates marker reduced past second indicates data bit value reduced past second indicates data bit value zero single bit marker sent way second minute second second minute reserved minute marker previously described red yellow bars indicate presence yellow representing higher strength referenced red lower strength referenced widest yellow bars represent markers represent data bits value intermediate width represent data bits value interpretation takes minute transmit complete time code bits utc time day year year century correction like time code tens units year transmitted unlike time code direct indication leap year receivers assuming year leap year correct year incorrect year hand receivers assume year leap year correct table shows interpretation bit column values example example shown day march utc effect previous utc effect utc leap second scheduled day year normally runs january december leap years december day day march instead march daylight saving time leap seconds time code contains bits announcing daylight saving time changes imminent leap seconds bit set near beginning month scheduled end leap second cleared leap second occurs bit set utc midnight comes effect cleared utc midnight standard time resumes bit set utc midnight comes effect cleared utc midnight standard time resumes bits differ changing current utc day local time local time bits change bits happens utc received mainland united_states depending local time zone begin end receiver eastern time zone utc correctly receive changing indication seven hours begins hours ends change local time display correct time receivers central mountain pacific time zones hours advance notice respectively leap second zero transmitted time code case minute preceded marker levels second minute hour tones carrier signal percent time code audio tones percent approximately maximum level voice recordings percent approximately transmission system broadcasts signal frequency frequencies use experimental signal uses sixth power connected dedicated antenna height corresponding approximately half signal signal radiation patterns antenna half antenna tower contains quarter element half uses guy wires connected tower sloped ground length formula additional elements half hourly station identification announcement identifies twice hour minutes past hour text identification follows accepts reception reports sent address mentioned station responds cards telephone service time signal accessed telephone calling boulder colorado equivalent time service operated accessed calling washington telephone calls limited minutes length signal delayed average
WWV (radio station)