RE: nRF9160-DK Minimum Required Signal Strength

Jeff4BLE — Mon, 18 Mar 2019 16:41:43 GMT

Thank you

RE: nRF9160-DK Minimum Required Signal Strength

Håkon Alseth — Fri, 15 Mar 2019 09:53:41 GMT

Hi Jeff,

No, just connect a SWF to SMA interconnect to "J1", and it'll break the connection to the antenna.

It's the same connector as used in the nRF52-DKs. Here's one from murata:

https://www.digikey.no/product-detail/en/murata-electronics-north-america/MXHS83QE3000/490-4982-ND/1775923

Cheers,

Håkon

RE: nRF9160-DK Minimum Required Signal Strength

Jeff4BLE — Thu, 14 Mar 2019 23:59:05 GMT

Thanks Håkon,

To add an external antenna, I assume this would be accomplished by removing L2, L3, C6 and connecting an antenna to J1?

Cheers,

Jeff

RE: nRF9160-DK Minimum Required Signal Strength

Håkon Alseth — Thu, 14 Mar 2019 12:18:08 GMT

Hi Jeff,

[quote user=""]1) What is the expected signal threshold needed to ensure reliable connection to a tower?[/quote]

Greater than the RX sensitivity, which is specified to -108 dBm:

https://www.nordicsemi.com/DocLib/Content/Product_Spec/nRF9160/latest/nRF9160_html5_keyfeatures

[quote user=""]2) At what signal strength, according to the link monitor, would we expect not to be able to connect to a tower?[/quote]

I have around -90 to -100 dBm at my desk, and that works fine. However; the specification depends on which band is in use as well:

https://www.nordicsemi.com/DocLib/Content/Product_Spec/nRF9160/latest/_tmp/alta-nRF9160/autodita/RADIOLTE/parameters-rf_spec_rx_m1

Parameters are a bit better for NB-IoT:

https://www.nordicsemi.com/DocLib/Content/Product_Spec/nRF9160/latest/_tmp/alta-nRF9160/autodita/RADIOLTE/parameters-rf_spec_rx_nb

[quote user=""]3) Is there anyway of improving this performance with the DK?[/quote]

The customer could try with an external antenna for the specific band (returned by AT%XCBAND) that is used in their region, but trying to place the kit in another corner of the building or similar can also have an effect.

[quote user=""]4) In the worst case location above, the customer uses T-Mobile as their mobile phone carrier. They have reliable connection with their phones, so the expectation is the nRF9160-DK should have a reliable connection. Please confirm if this may be do to T-Mobile using a lower frequency/band that the nRF9160-DK does not support? Or is this simply because T-Mobile hasn't approved us? The customer has tested with both iBasis and Hologram.io SIMs.[/quote]

Cat M1 can potentially use other channels or even towers. It depends on the coverage for Cat M1. It's hard to say without knowing the region and how the telecom vendor has deployed M1/NB-IoT in the area.

Kind regards,

Håkon