nrf9160 tx power

[EUREKA]

The nrf9160 tx power is 23DB ；

We is designing a procuct for ODM;

The size of product is small.

TRP requirements 20DB;

So the antenna  designs is difficult；

Now my problem is described below：

1. The nrf9160 tx power ≧22.5DB for delivery is possible According to our requirements；

2. The nrf9160 module tx power is not lower than 23DB；

 

[ketiljo]

The nRF9160 have max output power at 23 dBm. This is fixed in the modem FW and can't be changed

[EUREKA]

Hi 

Can you tell me what is the output power of the completed module；

Can you provide a partial list？

[ketiljo]

The output power is stated in the PS here: https://infocenter.nordicsemi.com/topic/ps_nrf9160/_tmp/alta.nRF9160/autodita/RADIOLTE/parameters.rf_spec_tx_m1.html and https://infocenter.nordicsemi.com/topic/ps_nrf9160/_tmp/alta.nRF9160/autodita/RADIOLTE/parameters.rf_spec_tx_nb.html

Also take a look at this document: https://www.nordicsemi.com/-/media/Software-and-other-downloads/SiP/nRF9160-SiP/nRF9160-Hardware-integration-guide.pdf

[JuhaK]

Hi,

According the documentation mentioned above, the maximum TX output power is 23dBm +/-2dB --> 21...25dBm, following 3GPP. We are measuring for example <22dBm at B12 (nRF9160-DK/CMW500). Based on the documentation this is according to the spec, but the question is that what is the actual typical TX power and standard deviation in normal conditions? Does our DK represent typical or corner sample?

We  have a suitable probe+cable for Murata LTE antenna connector, but due to the lack of cal kit, we are not able to measure its exact loss for accurate power measurements. Can you recommend/provide a suitable probe+cable with exactly known loss over frequency characteristics?

Thanks,

[ketiljo]

You will have about 1 dB loss in the cable (Murata cable assembly), depending a bit on the frequency. The DKs are typical.

[JuhaK]

Hi,

Coming back to the old TX power topic but now from the SAR point of view.

nRF9160 PS states that the maximum TX output power is 23dBm +/-2dB --> 21...25dBm, but I believe that this specified tolerance comes directly from 3GPP standards, and the actual nRF9160 max TX power tolerance is much smaller. In other words, I don't believe that any nRF9160 SiP module passes its production tests with TX power of  25dBm.

So, what is the highest LTE M1 TX output power that still passes nRF9160 production test? This is important as in SAR evaluation, also TX output power tolerance is taken into account: e.g 23.5dBm (more realistic guess) vs. 25dBm would reduce SAR by almost 20%.

Thanks!

[ketiljo]

I've checked this. The maximum output is 23 dBm. This is what it's calibrated for in production. So you can use 23 dBm as max power for the SAR calculations. 

[JuhaK]

Thanks, this is great news! To be even more specific, is the max exactly 23.0dBm or maybe your TX power calibration has some tolerance, so the accurate max could be e.g. 23.1dBm even if the target is 23.0dBm?

ps. correction to my previous percentage value above --> 30%

[ketiljo]

There will always be some uncertainty for this. If you state 23.5 dBm, you are absolutely sure sure as it will never be above this.