Range Ring analysis is done when an uncorrelated distress broadcast fails to produce an LOB. In this situation, what should the OU do?

• A. Plot a single circle around the last known point.
• B. Focus only on rings that heard the distress.
• C. Area scenario of the overlapping rings that heard the call, reduced by rings that didn't hear the call.
• D. Wait for additional distress broadcasts.

Answer: (C)

Range Ring analysis uses distance information from multiple receivers to constrain where a transmitter could be when a reliable bearing can’t be obtained. Each station that heard the distress creates a ring around its location at the estimated range to the transmitter. When you can’t trust a line of bearing, you look at where those rings overlap to define the probable area.

In this situation, you take the overlapping area formed by the rings from stations that did hear the distress and then remove any portions that fall outside the hearing reach of stations that did not hear it. This “intersection of rings heard, reduced by rings not heard” gives the most constrained search area given the available data.

This approach uses both positive information (where rings overlap) and negative information (where rings did not hear) to narrow the search efficiently. Plotting a single circle around the last known point ignores the heard/not-heard data and is less informative. Focusing only on rings that heard the distress ignores the valuable exclusion data. Waiting for more broadcasts delays action and doesn’t leverage what you already know.