I have made some tests and I have seen that the RSSI signal level decreases a lot with the distance, and up to exact 5 meters the level is very low, only 130. With that distance between air and ground modem, if I move the air antenna close to the AQ board the signal level decreased to 110. The ground module always has a higher level of noise than the air module and never is lower than 50, and with the distance the ground module increase the noise more than the air module.
See the images (5 meters, 0.5 meters) :
https://www.dropbox.com/sh/1sju8w2g0qr1ez0/hYu7qihwv1I think that I have never turned on the modems without antennas.
I'm going to replace these antennas and if the problem doesn't dessapear, i will buy another air radio to avoid the interferences. I don't see another way.
Could anybody help me about which kind of 433 mhz antennas are good?