Editing Broadcast automation (section)

==Early analog systems==
[[Image:WWJQAutomation.jpg|right|thumb|Harris automation system used at the former WWJQ (now [[WPNW]]) in 1993]]
Early automation systems were [[electromechanical]] systems which used [[Repeater|relay]]s. Later systems were "computerized" only to the point of maintaining a schedule, and were limited to radio rather than TV. Music would be stored on [[reel-to-reel audio tape recording|reel-to-reel]] audio tape. [[Subaudible tone]]s on the tape marked the end of each song. The computer would simply rotate among the tape players until the computer's internal clock matched that of a scheduled event. When a scheduled event would be encountered, the computer would finish the currently-playing song and then execute the scheduled block of events. These events were usually [[Radio advertising|advertisements]], but could also include the station's top-of-hour [[station identification]], news, or a [[commercial bumper|bumper]] promoting the station or its other shows.  At the end of the block, the rotation among tapes resumed.

Advertisements, [[jingle]]s, and the top-of-hour station identification required by law were commonly stored on [[Fidelipac]] endless-loop tape cartridges, known colloquially as "carts". These were similar to the consumer four-track tapes sold under the [[Stereo-Pak]] brand, but had only two tracks and were usually recorded and played at 7.5 [[Inch per second|tape inches per second]] (in/s) compared to Stereo-Pak's slower 3.75 in/s. The carts had a slot for a pinch roller<ref>{{cite web|last1=Wikimedia|first1=Commons|title=Cartridge Picture|url=https://commons.wikimedia.org/wiki/File:NAB-cartridge.jpg|website=Wikimedia Commons|publisher=Wikimedia|access-date=25 November 2016}}</ref> on a spindle which was activated by solenoid upon pressing the start button on the cart machine. Because the [[Tape transport#Capstan|capstan]] was already spinning at full speed, tape playback commenced without delay or any audible "run-up". Mechanical [[carousel]]s would rotate the carts in and out of multiple [[cassette deck|tape players]] as dictated by the computer. Time announcements were provided by a pair of dedicated cart players, with the even minutes stored on one and the odd minutes on the other, meaning an announcement would always be ready to play even if the minute was changing when the announcement was triggered. The system did require attention throughout the day to change reels as they ran out and reload carts, and thus became obsolete when a method was developed to automatically rewind and re-cue the reel tapes when they ran out, extending 'walk-away' time indefinitely.

Radio station [[WSJM-FM|WIRX]] may have been one of the world's first completely automated radio stations, built and designed by Brian Jeffrey Brown in 1963 when Brown was only 10 years old.{{Citation needed|date=July 2011}} The station broadcast in a classical format, called "More Good Music (MGM)" and featured five-minute bottom-of-the-hour news feeds from the [[Mutual Broadcasting System]]. The heart of the automation was an 8 x 24 telephone [[Stepping switch|stepping relay]] which controlled two reel-to-reel tape decks, one twelve inch [[Ampex]] machine providing the main program audio and a second [[RCA]] seven inch machine providing "fill" music. The tapes played by these machines were originally produced in the [[Mid-West Family Broadcasting|Midwest Family Broadcasting]] (MWF) Madison, Wisconsin production facility by WSJM Chief Engineer Richard E. McLemore (and later in-house at WSJM) with sub-audible tones used to signal the end of a song.  The stepping relay was programmed by slide switches in the front of the two relay racks which housed the equipment. The news feeds were triggered by a [[microswitch]] which was attached to a [[Western Union]] clock and tripped by the minute hand of the clock, then reset the stepping relay. Originally, 30-minute station identification was accomplished by a [[simulcast]] switch in the control booth for sister station [[WQYQ|WSJM]], whereupon the disc jockey in the booth would announce "This is WSJM-AM and... (then pressing the momentary contact button) ...WSJM-FM, St. Joseph, Michigan."  This only lasted about six months, however, and a standard tape cartridge player was wired in to announce the station identification and triggered by the Western Union clock.

[[Image:OpenReel-GMS204.jpg|200px|thumb|Solidyne GMS200 tape recorder with computer self-adjustment. Argentina 1980-1990]]
A different technology appeared in 1980 with the analog recorders made by Solidyne, which used a computer-controlled tape positioning system.  Four GMS 204 units were controlled from a 6809 [[microprocessor]], with the program stored in a [[Solid-state drive|solid-state]] plug-in [[memory module]]. This system has a limited programming time of about eight hours.

Satellite programming often used audible [[dual-tone multi-frequency]] (DTMF) signals to trigger events at [[Network affiliate|affiliate]] stations. This allowed the automatic local insertion of ads and station IDs. Because there are 12 (or 16) tone pairs, and typically four tones were sent in rapid succession (less than one second), more events could be triggered than by sub-audible tones (usually 25&nbsp;Hz and 35&nbsp;Hz).