alb12:
Yes Node 1 is the nRF24L01 + PA +LNA like this ( http://img.dxcdn.com/productimages/sku_222913_1.jpg ) with antenna 2db
And what can you do to get 8dB?
And the Node 31 has the nRF24l01 "classic"
Looking at the picture of the PCB with the nRF24 attached I wonder if the arrangement of parts interferes with the wireless signal propagation. In the projects I have built I have made sure that there is no metal very close to the antenna - even though I have not been building long-range projects.
And I can't remember if you said whether you have experimented with changing the orientation of your module (and hence the antenna) relative to Node1? IIRC correctly the flat face of the antenna should face the direction you want the signal to go.
...R