submitted by: Charles E. Kelly, 329th CRC 1951-1952


Part of fighting in a war, or Police action, as this forgotten war was called, is that the soldier has tunnel vision. That is, he very rarely sees the whole picture, only the tiny part he has in it, and only after the war is over is he able to determine if his tiny role had anything to do with the outcome.

As to the effectiveness of the work we did in the Army Security Agency in general, and our Low Level Intercept detachments in particular, I offer the following excerpts from:

The SIGINT (signal intelligence ) BACKGROUND.

In late 1951, in conditions reminiscent of France in 1917, ASA personnel inadvertently rediscovered an intercept technique used extensively in World War I. UN forces in Korea commonly planted sound detecting devices forward of their bunkers to give warning of approaching enemy troops; it was found that these devices also picked up telephone calls. This "ground-return intercept," using the principle of induction enabled collection of some Chinese and Korean telephone traffic.

The bad news was this intercept had to be conducted much closer to enemy positions than normal intercept, sometimes as close as thirty-five yards. This risk was assessed carefully and accepted.
Ground-return intercept (GRI) gave UN forces access to information on Chinese or North Korean patrols, casualty reports, supply problems, and evaluations of UN artillery strikes.

One colonel who participated in the GRI program was heard to remark that the information was so well appreciated by his soldiers that he had little trouble getting volunteers to go out at night and implant the equipment to make intercept possible.

A second innovation in COMINT production became one of the foremost producers of tactical intelligence for the U.S. military. This was low-level intercept (LLI).
Low-level teams initially consisted of an officer, driver, and one to three operators/translators, working out of a jeep. Over time the number of operators increased. Although the mobile operations were productive, the jeeps were considered too vulnerable, and operations were "dug in" in bunkers near the main line of resistance, as it was then called. The product was disseminated directly to combat units, usually at regimental level. The first attempt at front-line LLI in July 1951 proved only partially successful, but after some changes in equipment, the program began in earnest in August. Seven LLI teams were fielded by November 1951, and by the following May, ten LLI teams were in operation, with the planning for more. The success of the program is attested by the fact that by October 1952, fifteen LLI teams were at work, and by the end of the war, twenty-two LLI teams were active.

It was estimated that the tactical value of LLI  product lasted from twenty minutes to three days at best but, however perishable, it paid off. In early September, units in the U.S. 1st Cavalry Division area successfully repelled a heavy attack by the PLA. One important element in this victory was the advance warning given by the 1st Cav. LLI team.

Because the LLI teams dealt in perishable and current intelligence, not much long-term analysis was done, or possible. It thus became difficult to keep continuity on opposing units. These problems were eased somewhat with the creation of an LLI control section at ASA headquarters in Seoul in late 1951. This section collated reports from the field and service as a reference source on language problems and OB questions.