Con Son Island RVN, ARVN DF Detachment
The Army, Republic of Vietnam operated a AN/TRD-4A Radio Direction Finding site which was part of the overall DF Net and sub-nets in Southeast Asia. This was one of several sites operated by the ARVN. All, to the best of my knowledge, had American (read ASA) advisors attached -- normally Staff Sergeants. This photo below is circa 1968 March/April. th

The DF site was located just above the beach area at the left end of the beach as we look at it here in the area of those white blobs which are supposed to be buildings. The site advisor lived in the house just above the sand line of the beach on the right portion of the beach. The RED X in the line drawing to the left in the margin is more or less near the site area and advisor beach house seen in the photo above.
I have come across some mention on the Internet that the 175th RRC installed a detachment on the Island, if that is true then it had to have been after May 1968. I have not been able to confirm the information. -- Th ADDED February 2011 - Have confirmation of this. See Bill Kosek's remarks on the new Det 2, 175th RRC page.
The whitish strip of blob color in the center below the hillside is the run way, fuel storage and other bits and pieces. The main American activities consisted of a Coast Guard Loran station which was the main unit and all the various Americans assigned used its facilities such as mess hall, club, etc. The Navy operated some sort of small site up on the top of the hill to the left in the above photo and the Army and Contractors operated a Decca site in several trailers in the area just above the DF Site Advisors house.
Coast Guard 130 Supply flight on Con Son Island airfield. The CG considered their station "at sea" and they rationed beer as 2 per person daily and only opened the club on Saturday night, if my memory is not faulty.
Add your comments or memories:
I maintained all the ARVN DF sites from 1966-1969. From 1966-1967 I also maintained US sites at Ham Tan, Tay Ninh and Bien Hoa. In 66 myself and two operators went on a road trip to the DSU's to help with problems with the PRD-1's. we went to Pleiku, An Khe, Thuy Hoa, Nha Trang. All the units in the south came to us at White Birch.
I was on Con Son Island when that beach photo was taken, I was there from June 67 to July 68.......Did a lot of R & R on that beach at the end of the runway. I remember party flights coming out on Sundays from Saigon, mostly Embassy types with their guests. Always brought their own food/beer with them. I have a few photos.
Navy Seabees were building more permanent facilities for the Air Force radar site operators up on the hill, Army ( and a couple of Australian contractors ) ran the Decca Site. Most of these folks ate their meals at the Coast Guard Loran Station in the air-conditioned dining hall. Everyone gathered there watch the nightly movie, except on Saturday night. That's when the "club" opened up. I ran electricity down to the club so we could have lighting and listen to AFN radio. The only USO visitor we ever had was "Martha Raye". General Westmoreland stopped in once for a formal inspection. The only day I ever had to wear a "uniform".
Yes, the island could be turned into one really nice resort, given time and money for developement..............

Wayne Rupp was on Con Son in the 1960s as an advisor to the ARVN DF site.. Captions provided by Wayne
"I bunked in one of the buildings at the LORAN site and ate meals in their "mess hall", signal reception at the site was spotty at best since the LORAN antennas and a large hill they sat on were between the mainland and the DF site that was on the beach."