1. Check if the antennas of transmitter and receiver are damaged, especially the ones one receiver.

The silver part at the front of the antennas is the most important as it's the feeder line.

If the feeder line is damaged, keep flying will cause the unstable internal current which weaken the signal.

2. Check the RSSI value

Power on the transmitter and receiver with both antennas parallel and straight and within the distance of 30cm as picture below.

Then check the RSSI value. Range between 0~-30dBM is normal and if the value gets closer to 0, the signal is stronger. If the value is between -30~-90, signal is not good and the control distance would

be limited.

3. Check the flight environment if the antennas are all right and RSSI value is normal within the range

• Check if there is electricity substation or high voltage cable or wifi nearby.
• Check if the antenna of transmitter and receiver is damaged or welded joint.
• Installation: Do not get the receiver close to ESC/galvanometer/metal part of the flight.
• Let the end of the receiver antenna drooped and out to avoid the signal being blocked by the flight

frame.