ROCA is asport that requires less athletic skill and more technicalradio direction finding skills thanARDF. In a ROCA course, theradio transmitters put out very little power, typically 10 to 200mW, and can be received over only very short distances. Transmitters may identify themselves inMorse code or with voice recordings, and only transmit for ten seconds during every minute of the competition. The transmitters are physically small, and marked with a control card that is no larger than a typicalpostcard with a unique number identification. Decoy control cards may be placed in the competition area, as well, to force competitors to locate the actual transmitting devices. Because of the low power and short distances involved, most ROCA competitors walk the entire course, and focus their attention on theradio direction finding tasks rather thannavigation.
