Within this area are placed 5 transmitters that have to be found by the competitors. A sixth transmitter is usually provided at the finish line to help lost competitors find their way home. Each transmitter will be keying a unique identification code in the form MOE, MOI, MOS, MOH, MO5. These correspond to transmitter number one through five. At the competition there may be several classes of competitor, not all classes are required to find all transmitters.
Contestants are free to find the transmitters in any order they wish.
There is a time limit set for the course. Any competitor who has not finished within this time is disqualified. This time limit is set by the organizing group and takes into account, the number of competitors, the terrain and the length of the course. Region III IRAU rules recommends that it should be 100 to 140 minutes for a 4 to 7 km course. The five transmitters on the course operate sequentially on a common frequency.