Appendix 1: Selected Allied Monitoring Stations (MS) and Designators (USA=United States Army, USN=United States Navy)
| Site | Designator, “MS” |
|---|---|
| Vint Hill Farms, VA (USA) | 1 |
| Two Rock Ranch, Pentaluma, CA (USA) | 2 |
| Miami, FL (USA) | 3 |
| Asmara, Ethiopia (USA) | 4 |
| Territory of Hawaii (USA) | 5 |
| Amchitka, AK (USA) | 6 |
| Wireless Experimental Center, New Delhi, India (USA element) | 8, also 94 |
| Bellmore, NY (USA) | 9 |
| Santa Rosa, CA (USA) | 10 |
| Radio Corporation of America | 12 |
| Fort Sam Houston, TX (USA) | 17 |
| United Kingdom sources | 92 (Includes Beaumanor) |
| Commonwealth sources (Canada — Examination Unit, National Research Council) | 94; also, “E” |
| Cable Censor (United States Navy) | 59 |
| Federal Communications Commission | 81 |
| Cheltenham, MD (USN) | 56 also “M” |
| Bainbridge Island, WA (USN) | 54; also, “S” |
| Chatham, MA (USN) | "C” |
| Jupiter, FL (USN) | 55; also, “J” |
| Washington, D.C. (USN) | "N” ("NEGAT") |
| Winter Harbor, ME (USN) | "W” |
USN stations also carry their own designator. The “MS” system was unique to the Signals Intelligence Service and was a way to designate all of the so-called “sources of traffic” that included U.S. civilian agencies such as the Federal Communications Commission, commercial sources (Radio Corporation of America), and British and Commonwealth sites. — See NARA, RG 457, HCC, “Sources and Types of Traffic,” 9 November 1943, Box 936, NR 2694.