Foxes don't move during the competition. Foxes are not shown on the map with which the competitor is equipped. Map allow one to derive the progression of finding by drawing the directions on it. They must be at least 400m from each other and at least 750m from the start point. Start and finish are the only two location which are shown on the map.
Foxes transmits the verbal depending on it's identity.
There are two frequency ranges of operation. Each of the transmitters have fixed frequencies. Weighted about 1-3 pounds. Armed with the radio receiver competitor can get the direction of where the fox is located by the level of received signal. By looking at apple you can understand why it's not used for presize direction locating.