The Zigbee radio system used in the gates will give 500m between gate and Speedlink in optimal conditions.
One error new users make is they sit the Speedlink on the ground. This is a guaranteed way to limit range by more than 70%.
NEVER SIT THE SPEEDLINK ON THE GROUND
Make sure the Speedlink is sitting flat on a table, or the Speedlight carry case, with its antenna pointing up.
All gates must have antenna pointing up also.