RF-BM-ND04
Shenzhen RF-star Technology Co., Ltd.
Page 15 of 20
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2
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Make sure that there is no signal line or copper foil in each layer below the antenna.
（
3
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It is the best to hollow out the antenna position in the following figure so as to ensure that S11 of the module
is minimally affected.
Figure 8. Recommendation of Antenna Layout
Note: The hollow-out position is based on the antenna used.
4.6 Trouble Shooting
4.6.1 Unsatisfactory Transmission Distance
1.
When there is a linear communication obstacle, the communication distance will be correspondingly weakened.
Temperature, humidity, and co-channel interference will lead to an increase in communication packet loss rate. The
performances of ground absorption and reflection of radio waves will be poor, when the module is tested close to
the ground.
2.
Seawater has a strong ability to absorb radio waves, so the test results by seaside are poor.
3.
The signal attenuation will be very obvious, if there is a metal near the antenna or the module is placed inside of the
metal shell.
4.
The incorrect power register set or the high data rate in an open air may shorten the communication distance. The
higher the data rate, the closer the distance.
5.
The low voltage of the power supply is lower than the recommended value at ambient temperature, and the lower
the voltage, the smaller the power is.
6.
The unmatchable antennas and module or the poor quality of antenna will affect the communication distance.
4.6.2 Vulnerable Module
1.
Please ensure the supply voltage is between the recommended values. The module will be permanently damaged
if the voltage exceeds the maximum value. Please ensure the stable power supply and no frequently fluctuated
voltage.
2.
Please ensure the anti-static installation and the electrostatic sensitivity of high-frequency devices.
