Measure TX power & RX sensitivity

[dav01]

Hi, I know this topic has been up in several posts before, usually ends with, buy a LitePoint or Anritsu.

Assuming you want to do a poor mans measurement setup, just relying on a nrf52 being the measurement device,
what exact limitations would we get trying to measure tx power and rx sensitivity compared to a commercial test-system!?

let's say we calibrate (normalize) the text-jig once using a spectrum analyser, the nrf52840 can do -40dBm to +8dBm
something like a combination of a ~1mbps packet-rate measuring packet-loss on the other side (dropping tx power, test ad low/mid/high freq)

[dav01]

test-time can be "long", ok if the sequence takes 10-15 seconds

an attenuator around 50dB should be enough as I see it. needs to be tested in practice though and will be more sensitive in a 'non shield-box' environment.

[run_ar]

a 50 dB attenuator might be enough, just be aware that the accuracy at -40 dBm might be lower than for the output power setting from 0-8 dB. So maybe it's better to use more attenuation so you can measure sensitivity using the 2-8 dBm range. So use 2 or 0 for limit, then you can increase to up to 8 (maybe this gives to little range? Need to be tested).

I think bench measurement is likely to be fine, assuming this is for functional verification. I did some bench measurements using variable attenuation some time ago, and if I remember correctly this gave decent results for sensitivity measurements/verification. Packet loss is ramping up quite steeply, but if there are "busy" wifi blockers at the channel you are testing it will likely affect the result. Guess you could do a "sanity check" before testing by simply measuring the RSSI on the channel you want to test for a few seconds.