Editing Distant Early Warning Line (section)

==Operations==
[[File:DEW radar site in Greenland (cropped).JPG|thumb|A DEW station in western Greenland is visible in the distance beyond the snow-drifted equipment [[pallet]]s in the foreground of this photograph.]]
There were three types of stations: small unstaffed "gap filler stations" that were checked by ground crews only every few months during the summer; intermediate stations with only a station chief, a cook, and a mechanic; and larger stations that had a variable number of employees and may have had libraries, forms of entertainment, and other accommodations. The stations used a number of long-range [[L band]] – emitting systems known as the AN/FPS-19. The "gaps" between the stations were watched by the directional AN/FPS-23 [[doppler radar]] systems, similar to those pioneered only a few years earlier on the Mid-Canada Line. The stations were interconnected by [[White Alice Communications System|White Alice]], a series of radio communications systems that used [[tropospheric scatter]] technology.<ref name="dew2"/><ref name="dew3"/>

For stations at the western end of the line, buildings at the deactivated [[Pet-4]] United States Navy camp at [[Point Barrow]] were converted into workshops where prefabricated panels, fully insulated, were assembled to form modular building units {{convert|28|ft|abbr=on}} long, {{convert|16|ft|abbr=on}} wide, and {{convert|10|ft|abbr=on}} high. These modules were put on sleds and drawn to station sites hundreds of miles away by powerful tractors. Each main station had its own airstrip – as close to the buildings as safety regulations and the terrain permitted. Service buildings, garages, connecting roads, storage tanks, and perhaps an aircraft hangar completed the community. [[Drifting snow]] was a constant menace. Siting engineers and advance parties learned this the hard way when their tents disappeared beneath the snow in a few hours. The permanent H-shaped buildings at the main stations were always pointed into the prevailing winds and their bridges built high off the ground.<ref name="dew4"/>

The Arctic region was frequently transited by commercial aircraft on [[polar route]]s, either flying between Europe and western North America, or between Europe and Asia using Alaska as a stopover. These flights would penetrate the DEW Line. To differentiate these commercial flights from Soviet bombers, the flight crews had to transmit their flight plan to an Air Movement Identification System (AMIS) centre at either [[CFB Goose Bay|Goose Bay]], [[Edmonton]], or [[Anchorage, Alaska|Anchorage]]. These stations then passed the information on to the DEW Line.<ref name="adc31">[http://www.northcom.mil/Portals/28/Paper%20No%2031%20A%20History%20of%20the%20Dew%20Line,%201946-1964%20Full%20Release.pdf?ver=2017-03-16-115749-817 A History of the DEW Line, Aerospace Defense Command Historical Study No. 31, SECRET, June 1965.]</ref> If an unknown flight was detected, the DEW Line station would contact AMIS to see if a flight plan might have been missed; if not, NORAD was notified. Military flights, including B-52 bombers, frequently operated in the polar regions and used [[identification friend or foe]] (IFF) systems to authenticate the flight.<ref name="adc31" />

The early warning provided was useless against ICBMs and [[submarine]]-launched attacks. These were countered and tempered by the [[mutual assured destruction]] (MAD) philosophy. However, the scenario of a coordinated airborne invasion coupled with a limited nuclear strike was the real threat that this line protected against. It did so by providing Distant Early Warning of an inbound aerial invasion force, which would have to appear at the far north hours ahead of any warhead launches in order to be coordinated well enough to prevent MAD. A number of intermediate stations were decommissioned, since their effectiveness was judged to be less than desired and required. The staffed stations were retained to monitor potential Soviet air activities and to allow Canada to assert sovereignty in the Arctic. International law requires a country that claims territory to actively occupy and defend such territory{{Citation needed|reason=That last sentence needs to be backed up with some kind of evidence|date=July 2021}}.

Because the advent of ICBMs created another attack scenario that the DEW Line could not defend against, in 1958 the [[Federal government of the United States|United States Federal Government]] authorized construction of the Ballistic Missile Early Warning System (BMEWS), at a reported cost of $28 billion.<ref name="dew1"/>

In 1985, it was decided that the more capable of the DEW Line stations were to be upgraded with the GE AN/FPS-117 radar systems and merged with newly built stations into the North Warning System. Their automation was increased and a number of additional stations were closed. This upgrading was completed in 1990, and with the end of the Cold War and [[dissolution of the Soviet Union]], the United States withdrew all of its personnel and relinquished full operation of the Canadian stations to Canada. Costs for the Canadian sector were still subsidized by the United States. However, the American flags were lowered at the Canadian stations and only the Canadian flag remained.{{Citation needed|date=April 2021|reason=I can see the US flag at the Cambridge Bay site from the airport terminal}} The United States retained responsibility and all operational costs for North Warning System stations located in Alaska and Greenland.<ref name="dew1"/>