# A History of the DEW Line, 1946-1964 (ADC Historical Study No. 31)

Compiled by [Robin Monks](https://coldwar.tech/about), a Cold War archival expert.

*The Air Defense Command's own 1965 history of the DEW Line: the primary record of the AN/FPS-23 Fluttar Doppler fence, Project Red Sea, and the 1963 removal that halved the Line from 57 stations to 29.*

## Metadata

| Field | Value |
|-------|-------|
| Document Type | declassified |
| Creator | Air Defense Command, Directorate of Historical Services (author: Thomas W. Ray) |
| Date | 1965 |
| Classification | Confidential (since declassified) |
| Document ID | ADC Historical Study No. 31 |
| Original Language | english |

In June 1965, two years after the Air Force switched off every AN/FPS-23 on the DEW Line, the Air Defense Command’s historical office wrote up what had happened. Thomas W. Ray’s *A History of the DEW Line, 1946–1964* (ADC Historical Study No. 31, classified Confidential at creation and since declassified) is the closest thing to an official autopsy of the [bistatic Doppler fence](https://coldwar.tech/technologies/mcgill-fence) in American service.

This is the primary record for nearly every number in the Fluttar story: the Motorola-built sets at 475–525 megacycles and one kilowatt; the 28 four-to-five-man Intermediate stations; Project Red Sea’s 1958 finding that the Doppler system caught only 79 per cent of known penetrations while sounding “as many as four false alarms per minute”; and ADC’s November 1962 message to USAF that the set “has demonstrated virtually no operational usefulness”. This was followed by the inactivation of all 28 Intermediate sites, effective 21 July 1963, which halved the DEW Line from 57 stations to 29. It also contains a short early chapter on the [Mid-Canada Line](https://coldwar.tech/systems/mid-canada-line), recording that the 1953 Canada–US Military Study Group “concurred with a 1952 Canadian plan”, the US side’s own acknowledgement of whose idea the fence was.

Source: released by NORAD/USNORTHCOM; this copy via [governmentattic.org](https://www.governmentattic.org/NORAD-NORTHCOM/A%20History%20of%20the%20Dew%20Line%201946-1964.pdf). Public domain as a US government work.

## Related

- [The DEW Line](https://coldwar.tech/systems/dew-line) (Systems)
- [The Mid-Canada Line](https://coldwar.tech/systems/mid-canada-line) (Systems)

Tags: DEW Line, ADC, declassified, Fluttar, AN/FPS-23, Project Red Sea

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Canonical URL: https://coldwar.tech/archive/documents/adc-dew-line-history-1965
Last updated: 2026-07-15