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Zigbee RSSI is lower when PA/LNA is activated

Hi,

I'm testing a couple of EVBT840X boards from Fanstel which includes a PA + LNA within the nRF52840 module.

The source code is based on the ble_zigbee_dynamic_template example.

I added these defines:

// Fasntel PA + LNA

#define APP_PA_LAN

#ifdef APP_PA_LAN
#define APP_PA_PIN      17
#define APP_LNA_PIN     19
#define APP_CHL_PIN	8
#define APP_CPS_PIN	6
#endif

And then I included the source code they provide in the datasheet (www.fanstel.com/.../EV-BT840F-User-Manual.pdf) and calling this piece of code at the very beginning of the main function:

#ifdef APP_PA_LAN 

    nrf_gpio_cfg_output(APP_CPS_PIN);
    nrf_gpio_cfg_output(APP_CHL_PIN);
    nrf_gpio_pin_set(APP_CHL_PIN);
    nrf_gpio_pin_clear(APP_CPS_PIN); //enable
    pa_lna_init(APP_PA_PIN,APP_LNA_PIN);
#endif	

Setting the Tx Power to +8dBm in all the cases and boards separated with the same distance, I perdiodically invoke the function zb_zdo_get_diag_data() to get the rssi value.

With PA+LNA DISABLED = -50 dBm
With PA+LNA ENABLED = -70 dBm

-> What's wrong with this? Why the RSSI value is worst when the PA+LNA is enabled?
Note: I disabled everything related with bsp_leds and bsp_buttons




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