Furuno FM-8800D Service Manual page 195

NOTE:
Below chart shows the changing levels of FM-8800D RX IF LEVEL and AF NOISE.
Especially, IF LEVEL changes due to unsteadiness of RX gain. Also, antenna being
connected and not connected contributes to this change according to noise in the air as
well.
24000
23000
22000
21000
20000
19000
18000
17000
16000
15000
14000
13000
12000
11000
10000
9000
8000
7000
6000
5000
4000
3000
2000
1000
0
-130 -120 -110 -100 -90
Fig. 8.3.1 FM-8800D, Change of RX IF LEVEL and AF NOISE
CH16: IF Level
-80
-113dBm = 0dBu
CH18: IF Level
CH18: AF Noise
CH16: AF Noise
-70 -60 -50 -40 -30
SSG Level
8-15
8.3 T/A, TEST, RESET DSP
Reference only
-20 -10 0 +10 dBm