A Note from a Sanders Engineer Hello Jim John Egan sent your letter to Doug Barrett, a retired Sanders VP who was in charge of Sanders Surveillance Systems Division. Doug passed it on to me, since I was there when the Sanders part of "Phyllis Ann" was born. I don't recall the date, but George Woodrow, Dr. Ed Smiley and I flew through a snow storm to Ohio to deliver an RDF proposal to the Air Force at Dayton. Unfortunately the Dayton airport was closed down along with the base except for a small staff that was accepting industry RDF proposals. We landed in Columbus and rented an Olds-88, one of the first with front wheel drive and proceeded to Dayton. Our proposal was accepted and the DF system turned in to the ARD-18, which had a limited frequency range of 2-16 MHz. I was in charge of a Sanders antenna range and went on to design and test all of the Phyllis Ann DF arrays, the ALR-34, ALR-35 and ALR-38. These systems were based on the phase measurement direction finding principle, an idea that was invented (US Patent 3,325,813 June 13,1967) by two Sanders engineers, John Quick and Paul Sullivan. I don't remember many of the people associated with Phyllis Ann, but I do remember Maj. Dave Eddy one of the navigators that used our system extensively. This program jump started my technical career and resulted in the design and development of numerous DF systems for ships, submarines and aircraft. More recently I have been concentrating on adaptive array signal processing and superresolution DF techniques. I am putting together a CD ROM slide presentation that describes some of the history of these programs, some of the newer techniques and DF algorithms and some of the theoretical limitations. I retired, but I am still a part time Sanders Lockheed Martin employee, but spend most of my time here in Colorado. I do have pictures of C-47 Phyllis Ann aircraft and the electromagnetic models used for DF array design, but most of these are back in NH. A sad note: Of the three that went to Dayton on that cold wintry day, only I am still around. Keith Struckman