Ive got a strange network problem whit 3120,signal is perfect on 1800 Mhz,but on 900
 

Some ideas? coz i donno any

hello
 

Just change antenna switch.

thats not a strange problem, that is a very common problem. diplexer/ antenna switch- same thing. it is often best to replace the PA at the same time. clean contacts and tune the tx power levels, rx calibrations and check the rssi readings- make sure its around -60db. and the I/Q levels- tune them.

it vaz hagar,thx anyway