Frequently Asked Questions; Transmission Distance Is Short - Ebyte E22 T30D Series User Manual

Chengdu Ebyte Electronic Technology Co., Ltd.
Please check the stability of the power supply. The voltage cannot fluctuate greatly and frequently;
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When designing the power supply circuit for the module, it is often recommended to reserve more than 30% margin, so that the
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whole machine can work stably for a long time;
The module should be kept as far away as possible from power supplies, transformers, high-frequency wiring and other parts
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with high electromagnetic interference;
High-frequency digital wiring, high-frequency analog wiring, and power wiring must avoid the bottom of the module. If it is
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really necessary to pass under the module, assume that the module is welded on the Top Layer, and ground copper is laid on the
Top Layer of the module contact part (all copper is laid and Good grounding), must be close to the digital part of the module and
routed on the Bottom Layer ;
Assuming that the module is welded or placed on the Top Layer, it is also wrong to route traces randomly on the Bottom Layer
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or other layers, which will affect the module's spurious and receiving sensitivity to varying degrees ;
Assuming that there are devices with large electromagnetic interference around the module, which will also greatly affect the
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performance of the module, it is recommended to stay away from the module according to the intensity of the interference. If the
situation allows, appropriate isolation and shielding can be done;
Assuming that there are traces with large electromagnetic interference around the module (high-frequency digital,
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high-frequency analog, power traces), it will also greatly affect the performance of the module. It is recommended to stay away
from the module according to the intensity of the interference. If the situation allows, you can make appropriate adjustments.
isolation and shielding;
If the communication line uses 5V level, a 1k-5.1k resistor must be connected in series (not recommended, there is still a risk of
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damage) ;
Try to stay away from some TTL protocols whose physical layer is also 2.4GHz, such as USB3.0;
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The antenna installation structure has a great impact on module performance. Make sure the antenna is exposed and preferably
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vertically upward;
When the module is installed inside the case, you can use a high-quality antenna extension cable to extend the antenna to the
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outside of the case;
The antenna must not be installed inside a metal shell, as this will greatly reduce the transmission distance.
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12. Frequently Asked Questions

12.1 Transmission distance is short

When there are straight-line communication obstacles, the communication distance will be correspondingly attenuated ;
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Temperature, humidity, and co-channel interference will cause the communication packet loss rate to increase ;
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The ground absorbs and reflects radio waves, and the test effect is poor when close to the ground ;
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Seawater has a strong ability to absorb radio waves, so the seaside test results are poor ;
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If there are metal objects near the antenna, or if it is placed in a metal case, the signal attenuation will be very serious ;
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The power register setting is wrong and the air rate is set too high (the higher the air rate, the closer the distance) ;
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The low voltage of the power supply at room temperature is lower than the recommended value. The lower the voltage, the
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smaller the power generated ;
There is a poor match between the antenna and the module or there is a problem with the quality of the antenna itself.
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