Editing Automatic transmission system (section)

==Theory of operation==
An ATS monitors conditions such as [[voltage]], [[current (electricity)|current]], and [[temperature]] within the transmitter cabinet or enclosure, and often has external [[sensor]]s as well, particularly on the antenna. Some systems have remote monitoring points which report back to the main unit through [[telemetry]] links.<ref name="HH2007">{{Cite book |last=Hallikainen |first=Harold |title=National Association of Broadcasters Engineering Handbook |date=2007 |editor1-last=Williams |editor1-first=Edmund A. |editor2-last=Jones |editor2-first=Graham A. |editor3-last=Layer |editor3-first=David H. |editor4-last=Osenkowsky |editor4-first=Thomas G. |publisher=Focal Press |isbn=978-0-240-80751-5 |edition=10th |location=Burlington, Massachusetts |chapter=Transmitter Remote Control and Monitoring Systems |oclc=858995417}}</ref>

Advanced systems can monitor and often correct other problems which are considered [[mission-critical]], such as detecting ice on antenna elements or [[radome]]s and turning on heaters to prevent the [[VSWR]] (power reflected from a mismatched antenna back into the transmitter) from going too high.  High-power stations that use [[desiccation]] [[pump]]s to put dry [[nitrogen]] into their [[feedline]] (to displace moisture for increased [[electrical efficiency|efficiency]]) can also monitor the [[pressure]].  [[Electrical generator|Generator]]s, [[battery (electricity)|batteries]], and incoming [[electricity]] can also be monitored.<ref name="HH2007"/>

If anything goes wrong which the ATS cannot handle, it can send out calls for help, via [[pager]], [[telephone]] [[voice message]], or [[transmitter/studio link|dedicated telemetry link]]s back to a fixed point such as a broadcast [[studio]].  Other than possibly listening for [[dead air]] from the [[studio/transmitter link]], an ATS does ''not'' cover the programming or the studio equipment like [[broadcast automation]], but rather only the "[[transmitter plant]]".<ref name="HH2007"/>

An ATS can also be used to automate scheduled tasks, such as lowering an [[AM radio]] station's transmission power at sundown and raising it at sunrise to meeting license requirements for different [[radio propagation|propagation]] patterns at day and night.<ref name="HH1996"/>