Hi Charles,
Your range test has been very interesting. I had a slightly different question. I would be happy if you answer it:
The nRF IC would be discarding the signal below a certain power. What is the threshold power required at the receiver of nRF IC for it to successfully receive the signal? Normally it is mentioned in the datasheet that the sensitivity of the reciever is -64dBm. Can you adjust it for higher values(Like -32dBm) as per our requirement?