nRF51 DK SDKv10 with S110 iBeacon beacon example: How to increase TX power?

[Nitin Solanki]

My requirement is simple: Want to increase the iBeacon transmit power to (i.e. -4, 0 or 4dbm). In the beacon example, I tried adding in the main loop after calling advertising_init():

    uint32_t err_code = sd_ble_gap_tx_power_set(TX_POWER_LEVEL);
		APP_ERROR_CHECK(err_code);

where TX_POWER_LEVEL is defined as 0.

However when I execute the code on nRF51 DK (PCA10028), I am not able to observe increase in transmit power. I still see it as default (-30/-40dbm).

I request you to provide an example, where I can increase the iBeacon transmit power. I would further like to also tweak the advertising interval to optimize power usage.

Thank you and best regards,

Nitin

[Nitin Solanki]

I tried the same with S130 softdevice as well, but I am getting the same issue. The actual transmit power is not increasing

[Kenneth]

Hi, how are you measuring this? Are you observering RSSI on a peer device or are you measuring conducted using a spectrum analyzer?

[Kenneth]

Is there any difference if you use:

int8_t tx_power = 0; // -40, -20, -16, -12, -8, -4, 0, 3, and 4

err_code = sd_ble_gap_tx_power_set(tx_power);

APP_ERROR_CHECK(err_code);

[Nitin Solanki]

I have tried various values from -20 to +4, but there is no difference in measured rssi@1m. I have also tried the same code on our custom PCB with nRF51822. I am not getting higher transmit power there as well.

[Nitin Solanki]

I tried it, and do see some effect on the output.

With tx_power = -40, I got rssi of -100 at 1m.

With tx_power = 4. I got rssi of -61 at 1m.

Is it normal that there is such a huge difference between tx power and rssi@1m?

When it is transmitting at +4dbm, shouldn't I receive a much stronger signal than -61dbm at 1 meter?

Thanks,

Nitin

[Nitin Solanki]

And all of the above measurements are in line-of-sight with various orientations.

[Kenneth]

This is normal I would say.