NRF52840 Coded Phy Sensitivity with soft device 6.0.0-6.alpha

[Christian]

Hi,

although the NRF52840 has a nominal receiver sensitivity of -103 dbm I am only able to get a sensitivity of around -97 dbm. I know there was a bug in older soft device versions resulting in a decreased sensitivity, but I am using soft device 6.0.0-6.alpha in which this bug should be fixed. I used a modifiedatt_mtu_throughput example to print the RSSI when changed, but connection between two nrf52840 boards is still lost at around -97 dbm.

Is there anything else that needs to be considered apart from the soft device version?

Thanks in Advance

Christian

[MartinBL]

A second thing to mention is that although we initially stated that the 840 would be capable of +9dBm output power we have had to reduce that value to +8dBm. This is documented in the OPS 0.5.1. Have you measure the actual output power?

[matsublox]

Picking up this thread again ... We have Rev B devices and would like to do some range measurements for an application where the range is very important. We are using your range measurement example. This means that we want to have an optimal setup for this.

When is the Softdevice with support  for Rev B sensitivity fix available?

If we use the Rev B devices and -6 revision of the Softdevice do we still loose about 6 dBm in sensitivity?

[MartinBL]

Hi,

Alpha -6 is not strictly compatible with Engineering B silicon (refer to the compatibility matrix). 

1. The alpha -6 includes a workaround for erratum [164] RADIO: Low selectivity in long range mode (which isn't actually necessary on Engineering B since it is fixed in silicon).
2. The alpha -6 lacks a workaround for erratum [191] RADIO: High packet error rate in BLE Long Range mode which will degrade the range performance. 

So I wouldn't recommend doing long range tests on Engineering B with alpha -6. Production versions of both the IC and an accompanying Softdevice are just around the corner. 

 

[matsublox]

What about the combination of production SW and Rev B chip. Will that be appropriate to do range testing with?

[MartinBL]

Unfortunately we only recommend sticking to the Compatibility matrix and use development SW on development HW.

[Susheel Nuguru]

The documentation was updated today, Engineering B chips are supported by SDK15 and S140v6.0 production release. Link to compatibility matrix is here