We investigated telemetry error using a dual yagi null-peak antenna system mounted on a pick-up truck. One-hundred transmitters were placed in known locations in forest and field habitats on the Remington Farms study area. Most (755 of 830) pairs of azimuths gave useable estimates of the transmitter location. The median error distance (distance from the estimated to known transmitter location) was 133m (N = 746, range = 2 - 1559 m). Error distance (ED) was closely related to 2 independent variables: the deviation of the intersection angle from 90° (DEY) and the mean distance from the receivers to the estimated location (RECDIST); these are variables that can be calculated in the field with a computer while radio locations are being taken. The model of ED = -9.19 DEV + 0.72 DEy2 + 0.21 RECDIST was highly significant (R2 = 0.82). Predicted error could be used as an objective criterion to reject telemetry locations with unacceptable error.