Rx sensitivity of nRF24AP2-8ch

[WrightLin.Avnet]

Hi Great support team:

Currently our client found their product lost packets of CTF profile at outdoor, they are trying to figure out if it is related by RF signal strength.

But, as we know, there is no such method that could test Rx signal. (We have tried to record RSSI value while receiving packet, but the functionality is not support by nrf24ap2).
Somehow, in the datasheet, there is a rx sensitivity item of nrf24ap2, which shows -85dbm.

So,I'd like to know how do you test Rx sensitivity of nRF24AP2? And what should we prepare for it?

Thanks for your patience.

Sincerely, Wright

[ovrebekk]

Hi Wright

I assume the customer has designed their own PCB, or have they used a module?

Is this new hardware, or is it hardware that has been working fine in the past and is now showing problems?

I haven't worked with the nRF24AP2 in a while, but there are some test modes that are typically used to ensure that the RF layout is designed properly. This can be used to optimize the hardware performance when doing a custom hardware design. 

Best regards
Torbjørn

[WrightLin.Avnet]

Hi ovrebekk: 

Thanks for answering, we have reviewed  their PCB design (RF part) and used CW test to make sure their product could send Tx signal properly. But as what I mentioned, the data of CTF are still lost sometimes. 

They use nrf24Ap2 as a sensor hub of bike, collecting CTF data while user riding a bike. The data of CTF include two part : cadence and power. 

The strange thing is part of the power data were lost while cadence data are not.
And they've test it with another Garmin sensor hub, the data lost situation was not shown anymore. 
So, I think it may proof that sensor data are correctly sent.

They trying everything to figure out what's going on there, and Rx sensitivity seems like a good target to check first. Maybe we could do something to make sure the data lost situation is not related to RF.

  

[ovrebekk]

Hi Wright

Did you also send they RF layout and schematic to us for review?

It would be nice to have a look at their design to see how they have handled the RF circuitry and antenna.

The placement of the sensor on the bike can also be relevant. I assume the issue has not been discovered under lab conditions, but happens in the field? 

Best regards
Torbjørn

[WrightLin.Avnet]

Hi ovrebekk: 

Yes, like you said, it's only happened in the field. Here is the schematic of their product, maybe you could take a look on it.

SCHEMATIC1 _ 43. ANT+_20190110.pdf  

[ovrebekk]

Hi Wright

Thanks for the schematic.

In order to evaluate the RF performance I will also need the RF layout, as the schematic doesn't say anything about the placement of components, how the ground plane looks, how the signals are routed etc.

Ideally the RF layout should be shared in Gerber format, as it makes it easy for us to look at the different PCB layers in detail. 

PDF is also OK, if the layers are shown individually. 

Best regards
Torbjørn