RSSI is lower then it must be
I have two REB215-XPRO boards without extension boards. It has AT86RF215 chips on each board. I can control them with STM32 by using SPI protocol. I made the program that i can use one board like transmitter and the second like receiver, so i can see how much frames it sends and few parameters of transmition (I'm trying to measure transmission loss). The boards has 5 centimeters between each other.
When i use the spectroanalizer with transmitter, i can see power of transmition like +7dBm, but when i read the RSSI level on receiver with the same parameters of transmition, it is like -30 - -40 dBm. And if i change the settings like modulation, bandwith, gain on receiver, power target level and other, they are not has any influence on that strange RSSI, its always really lower then it have to be. Whats could be the problem?
Here is my settings of registers for transmition and receiver:
The order of the parameters is the same as in my program, if it has any influence.