Editing Semi-Automatic Ground Environment (section)

===Radar stations===
[[SAGE radar stations]], including 78 [[DEW Line]] sites in December 1961,<ref>{{Cite journal |last=Furlong |first=R. D. M.  |date=Jun 1974 |title=NORAD—A Study in Evolution |journal=International Defense Review |volume=7 |issue=3 |pages=317–9}} (Schaffel p. 268 citation 39)</ref> provided radar tracks to DCs and had [[Frequency Diversity Radar Program|frequency diversity (FD) radars]]<ref>{{Cite report |year=1955 |title=Project LAMPLIGHT |type=Final Report |location=copy in AF/CHO}} (Schaffel Ch 8 footnote 64 cites this report on pp. 223/312)</ref> [[United States Navy]] [[picket ships]] also provided radar tracks, and seaward radar coverage was provided. By the late 1960s [[EC-121 Warning Star]] aircraft based at [[Otis AFB]] MA and [[McClellan AFB]] CA provided radar tracks via automatic data link to the SAGE System.{{r|Schaffel}}<!--{{rp|220-1}}--> [[Civil Aeronautics Administration (United States)|Civil Aeronautics Administration]] radars were at some stations (e.g., stations of the [[Joint Use Site System]]), and the [[ARSR-1]] [[Air Route Surveillance Radar]] rotation rate had to be modified "for [[Identification friend or foe|SAGE [IFF/SIF] Modes III and IV]]" ("antenna gear box modification" for compatibility with FSQ-7 & FSG-1 centrals.){{r|NORAD1958A}}{{rp|21}}