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DA14531 module External Antenna?

DA14531 SmartBond TINY Module

5 months ago

Posted by magergar 50 points 1 reply
0 upvotes

Currently I have my bluetooth inside an aluminium case and the signal is dimmed

It is possible to connect an external antenna to the DA14531 SmartBond TINY Module? if yes how can I do it?

5 months ago

PM_Dialog

Hi magergar,

Thanks for your question and for your interest in our TINY module solution.

If there is no “open window” in the aluminium case, this will have an impact on the TX power and might be a bit tricky for the radio. Would it be possible to have a “window”, or it is a “closed box”?

What is the TX power you tested?

If you check the module’s datasheet, you will see that there is no external antenna connection. There is a printed antenna inside the module. So, it’s not possible to use an external antenna.

What you can do in order to improve the signal strength, is to set the TX power @ 2.5dBm, which is the maximum TX power.

The DA14531 (and the TINY module) has configurable TX power from-19.5 dBm to +2.5 dBm.

To change it, you should do some SW modifications – see below :

-          Use the rf_pa_pwr_set() API  in order to select the Tx output power level- it can be found in the rf_531.h / .c. The preferable Tx level can be selected from the rf_tx_pwr_lvl_t enumeration, which defines the transmit output power level from -19.5 dBm up to +2.5 dBm. The selected value will be applied to hardware when set_recommended_settings() is called.

-          Check rf_init_func() in ble_arp.c. The default value is at 0dBm -  rf_pa_pwr_set(RF_TX_PWR_LVL_0d0);

-          This API can be called in the app_on_init callback and prior to default_app_on_init().

Thanks, PM_Dialog