In optimum environment the range of the Firstbeat Team Receiver (30, 80 & 100) is 200 meters. To ensure optimal range and data quality the receiver should be placed to open place where is no constraints between athletes and receiver. Avoid places with tall buildings, thick shrubs and trees. The Receiver should have a clear "visual" to the athletes wearing the heart rate belts.
If you have the elbowed antenna, turn it so that it points up. Also place the receiver over 1.5m from ground. You can use a tripod or other platform to raise the receiver higher. Make sure that the tripod or the platform stands firmly on the ground.
The smaller Receiver 10 device's range is 30 meters. Same basic rules to optimize the signal apply to the Receiver 10 as to the Team Receivers.