interference

[magno22]

Dears,
I have question about spectrum analyzer. I detected some signals on 1800Mhz and if i turn off GSM900 station this signal not appeared. So i asked our vendors they answered "this signal is created input of spectrum analyzer". So then i installed band pass filter between spectrum analyzer and receiver antenna, filtered GSM900 signals. After the installing filter/blocked 900Mhz signal/ 1800Mhz signal disappeared. Is it possible? Any one faced such kind of problem?

[Philippe]

Is it intermodulation product creating a spike in 1800MHz band? Or is there any 1800MHz base station around?

[magno22]

Is it intermodulation product creating a spike in 1800MHz band? Or is there any 1800MHz base station around?
I think this is intermodulation product of GSM900 station. But our vendor told me this signal is created on input of receiver. To confirming this idea we installed band pass filter /pass 1800Mhz and block 900Mhz/ between spectrum analyzer antenna and spectrum analyzer. Is this idea reasonable?