Dear Mr. Stevenson,
Thank you for posting your request on History Hub!
The National Archives at College Park - Textual Reference (RDT2) has custody of microfilm copies of operational records relating to U.S. Army Air Force/U.S. Air Force units. We searched the Air Force History index to the microfilm and located 18 files related to Cam Ranh Bay Air Base in 1966 and 12 files related to Nha Trang Air Base in 1966. Please read the brief Abstract to determine which records you are interested in and click on the specific PDF icon. In the PDF listing, the IRISREF is the microfilm reel number and note the FRAME and FRAMELST numbers for the location on the reel. If the reel number begins with A, B or C, please contact RDT2 via email at firstname.lastname@example.org for more information about them.
If the reel number begins with D - Z, the microfilm is still security classified and RDT2 will not be able to make the reel available to you. The original paper copy from which the film was created is still in the custody of the Air Force Historical Research Agency (AFHRA) and has been declassified. To obtain copies of these records, please follow the instructions on this page. If there is no IRISREF information, only AFHRA has the records.
Next, we located the series Signal Unit Records, ca. 1965 - ca. 1973 in the Records of U.S. Forces in Southeast Asia (Record Group 472) that contains records related to Cam Ranh Bay and Nha Trang, and the Signal Section Daily Journals, 10/1967 - 4/1972 in Record Group 472 may be useful for your research as well. These records have not been digitized. Please contact RDT2 at email@example.com for more information about these and similar records.
We also located 3 cartographic files related to Cam Ranh Bay and 10 cartographic files related to Nha Trang in various records groups that might be of interest to you. Some of these files have been digitized and can be viewed online using the Catalog. For access to the non-digitized records, please contact the National Archives at College Park - Cartographic (RDSC) at firstname.lastname@example.org.
Plus, we located the series Photographs of U.S. Army Operations in Vietnam, 1963-1973 in the Records of the Office of the Chief Signal Officer (Record Group 111) that includes some pictures of communication facilities including radar stations and that contains 2 files related to Cam Ranh Bay and 2 files related to Nha Trang. These images have not been digitized. Please contact the National Archives at College Park - Still Pictures (RDSS) at email@example.com for assistance with these records.
Due to the continued impact of COVID-19, you may experience a delay in receiving an initial acknowledgment as well as a substantive response to your reference request from RDT2, RDSC, and RDSS. We apologize for this inconvenience and appreciate your understanding and patience as we balance mission-critical work and the safety of our staff during the pandemic. Please check NARA’s web page about COVID-19 updates for the latest information.
We hope this is helpful. Best of luck with your research!
Thank youRachael for your diligence and suggestions. I had simultaneously submitted this query to AFHRI, and they responded very quickly with the answer: it was on the summit of Hon Tre Island just east offshore Nha Trang, as shown on this 1972 aero-navigational map from the U of Texas map collection (enlarged for Nha Trang area).
I offer this in case others might be interested.