How to get the RSSI calibration constant for a si4463

[kml183]

Hi there!

I have been playing with the rf4463 1W G(FSK) 433Mhz module from nicerf recently. I am trying fetch/compute the RSSI after each rx packet. From the datasheet:

The RSSI value read by the API could be translated to dBm by the following linear equation:
RSSI (in dBm) = (RSSI_value /2) – RSSIcal
RSSIcal in the above formula depends on the matching network, modem settings, and external LNA gain (if
present). The RSSIcal value can be obtained by a simple calibration with a signal generator connected at the
antenna input. Without external LNA, the value of RSSIcal is around 130 ±30.

I don't have a signal generator, is there any way I can figure out that RSSIcal constant with another module?

lets say I connect two modules with a coax and use a 30dB attenuator, as well as setting the power to be max (1W). On the reciever I am testing, would the RSSIcal be:

RSSIcal = (RSSI_value / 2) - 36 + 30? 

Thanks! 

[kml183]

So I contacted the NiceRF which makes the RF module that I am using (RF4463F0) that wraps the si4463. They were able to give me some test data to use to determine the calibration constant, see attached. From this data I was able to draw a best fit line using matlab's polyfit function, and then determine the y intercept of that line to be 133.765.

I mistakenly added another screenshot that was unrelated, and I am not sure how to delete it!