Sign-on and sign-off

A sign-on (or start-up in Commonwealth countries except Canada) is the beginning of operations for a radio or television station, generally at the start of each day. It is the opposite of a sign-off (or closedown in Commonwealth countries except Canada), which is the sequence of operations involved when a radio or television station shuts down its transmitters and goes off the air for a predetermined period; generally, this occurs during the overnight hours although a broadcaster's digital specialty or sub-channels may sign-on and sign-off at significantly different times than its main channels.
Like other television programming, sign-on and sign-off sequences can be initiated by a broadcast automation system, and automatic transmission systems can turn the carrier signal and transmitter on/off by remote control.
Sign-on and sign-off sequences have become less common due to the increasing prevalence of 24/7 broadcasting. However, some national broadcasters continue the practice; particularly those in countries with limited broadcast coverage. Stations may also sometimes close for transmitter maintenance, or to allow another station to broadcast on the same channel space.
Sign-ons, like sign-offs, vary from country to country, from station to station, and from time to time; however, most follow a similar general pattern. It is common for sign-ons to be followed by a network's early morning newscast, or their morning or breakfast show.
Some broadcasters that have ceased signing on and signing off in favour of 24-hour broadcasting may perform a sign-on sequence at a certain time in the morning (usually between 4:00 and 7:00 a.m.) as a formality to signify the start of its operating day (in the United States, the broadcast logging day begins at 6:00 a.m. local time).
The sign-on sequence may include some or all of the following stages, but not necessarily in this order:
While most of these sign-on steps are done as a service to the public, or for advertising reasons, some of them may be required by the government of the country.
Sign-offs, like sign-ons, vary from country to country, from station to station, and from time to time; however, most follow a similar general pattern. Many stations follow the reverse process to their sign-on sequence at the start of the day.
Many stations, while no longer conducting a sign-off and being off air for a period of time each day, instead run low-cost programming during those times of low viewer numbers. This may include infomercials, movies, television show reruns, simple weather forecasts, low cost news or infotainment programming from other suppliers, simulcasts of sister services, or feeds of local cable TV companies' programming via a fiber optic line to the cable headend. Other broadcasters that are part of a radio or television network may run an unedited feed of the network's overnight programming from a central location, without local advertising. During what are otherwise closedown hours, some channels may also simulcast their teletext pages or full page headlines with music or feeds from sister radio stations playing in the background. Some stations, after doing a sign-off, nonetheless continue to transmit throughout the off-air period on cable/satellite; this transmission may involve a test pattern, static image, local weather radar display, teletext pages or full-page headlines which was accompanied by music or a local weather radio service.
Some broadcasters that have ceased signing on and signing off in favour of 24-hour broadcasting may perform a sign-off sequence at a certain time in the night (usually between 10:00 p.m. and 1:00 a.m.) as a formality to signify the end of its operating day (in the United States, the broadcast logging day ends at 12:00 midnight local time).
The sign-off sequence may include some or all of the following stages, but not necessarily in this order:
Some countries have a legal protocol for signing-off: in the United States, the minimum requirement is the station's call sign, followed by its designated city of license. Many stations do include other protocols, such as the national anthem or transmitter information, as a custom, or as a service to the public.
In the United Kingdom, before the introduction of 24-hour television, there was no known legal protocol for a sign-off: BBC One and many ITV regions customarily included a continuity announcement, clock and the country's national anthem (for BBC One Wales and HTV Wales, Hen Wlad Fy Nhadau was also played beforehand), while Granada and Channel 4 signed-off with just an announcement, clock and ident, and BBC Two, Yorkshire and Border closed down with an announcement over their station clock.
In Germany, it is a custom to play the national anthem (for Bayerischer Rundfunk and stations owned by ProSiebenSat.1 Media, the Bayernhymne was also played beforehand) and the European Union anthem. ARD started playing the national anthem at closedown on May 23, 1985.
In Spain, it is a custom to play the national anthem (for RTVA, EITB and Televisión de Galicia, the respective anthems of their autonomous communities would also be played beforehand).
In a number of countries closedowns formerly took place during the daytime as well as overnight. In the United Kingdom, this was initially due to government-imposed restrictions on daytime broadcasting hours, and later, due to budgetary constraints. The eventual relaxation of these rules meant that afternoon closedowns ceased permanently on the ITV network in October 1972, but the BBC maintained the practice until Friday 24 October 1986, before commencing a full daytime service on the following Monday. Afternoon closedowns continued in South Korea until December 2005. Hong Kong's broadcasting networks (particularly the English-speaking channels) also practiced this until mid-2008. In these cases, the station's transmitters later did not actually shut-down for the afternoon break; either a test-card was played or a static schedule was posted telling viewers of the programming line-up once broadcasting resumes.
In Indonesia, restrictions on broadcast hours were also implemented in July 2005 as part of an energy saving campaign. Three years later, they were implemented again due to the electricity crisis.
Medium wave radio is a special case due to its unusual propagation characteristics; it can bounce hundreds of miles by reflecting from the upper atmosphere at night, but during the day these same layers absorb signal instead of reflecting. A few powerful regional clear-channel stations have an extensive secondary coverage area which is protected by having smaller local co-channel stations in distant communities sign off shortly before sunset. A frequency on which a broadcaster has to drastically reduce power or sign off entirely at sunset was traditionally the least desirable assignment, which would usually go to small or new-entrant stations when all of the more favourable slots were already allocated.
These AM daytimers are becoming less common as stations (and audiences) migrate to FM or to frequencies vacated by the closure of other stations, but a handful still exist in the US and México.
During religious holidays or occasions, Doordarshan and Akashvani will broadcast a prayer of any religion through the day, a week or a month (e.g. During Ramadan, a reading from the Quran, a Muslim quote, or a call for Azan and Fajr prayer will be broadcast. During Lent, a Christian prayer, a hymn or a psalm will be broadcast).
In Bali during Nyepi, all terrestrial television and radio stations go off-the-air.
During Yom Kippur, virtually all radio and television stations based in Israel go silent for 24 hours, as required by law. However, most international networks (e.g. CNN) continue to broadcast as usual.
During Ramadan, Malaysian public broadcaster RTM operated TV1 24 hours a day instead of signing off. In 2012, TV1 broadcast 24 hours a day during the London Olympics in 2012, due to the time difference. This would become permanent in August 2012, to coincide with their sister channel TV2 by showing reruns from the broadcaster's archive library and movies on early mornings before start-up.
During the Holy Week in the Philippines that occurs anywhere between the last week of March to the third week of April (depending on the Roman Catholic liturgical calendar), terrestrial television and radio stations continue their regular schedules from Palm Sunday until Holy Wednesday. From the midnight of Holy Thursday until the early hours of Easter Sunday (before 4 AM PHT), most commercial television and radio networks either remain off-the-air or reduce their broadcast hours. Stations that opt to remain on-air provide special programming such as Lenten drama specials, news coverage of various services and rites, Christian and mellow music content. Member stations of the Catholic Media Network prominently follow the latter pattern, broadcasting Paschal Triduum services and other similar programming.
Campus radio stations' operations during this time are left to the discretion of their respective schools, colleges, or universities by either closing down on the afternoon and/or evening of Holy Wednesday or remaining off-air for the entire Holy Week.
On cable, satellite, and live TV streaming, with the exception of specialty channels that broadcast horse racing, cockfighting, and the like that remain dormant during this period, most international networks distributed in the Philippines or Philippine-exclusive cable channels either continue to broadcast their 24/7 regular programming service week-long or provide specially-arranged schedules from Holy Thursday to Black Saturday.