When are 2 Out of Pass Band Signals a Problem?
•If you know the close-in dynamic range of a radio, at what signal level will IMD start to be a problem?
•Assume   S9 = 50 mV   which is   –73 dBm 
•Assume a typical radio:
u 500 Hz CW filter u Noise Floor of -128 dBm u Preamp OFF
Dynamic Range Signal Level Causing IMD = Noise Floor
55 dB S9
60 dB S9 + 5 dB
65 dB S9 + 10 dB
70 dB S9 + 15 dB
75 dB S9 + 20 dB
80 dB S9 + 25 dB
85 dB S9 + 30 dB
90 dB S9 + 35 dB
95 dB S9 + 40 dB