Standard Communications mt930b, Руководство по обслуживанию, Страница: 64 / 155

Maintenance
Page 6-32 Service Manual MT930B
6. Adjust LH31 so the –3 dB BW falls inside the frame for adjustment.
▼ 2: 58.5 MHz
▼ 3: 61.5 MHz
▼ 4: 78.5 MHz
▼ 5: 79.5 MHz
7. Select IF BW 25 MHz. Call up the file 25MHz_BPF, and adjust the variable
attenuator so the point of intersection within the frame and marker
▼ 1
(70 MHz point) match.
8. Adjust LH11 so the –3 dB BW falls inside the frame for adjustment.
▼ 2: 57.0 MHz
▼ 3: 58.0 MHz
▼ 4: 82.0 MHz
▼ 5: 83.0 MHz
27 MHz BPF Adjustment
Adjustment Procedure:
1. See Figures 6-17 and 6-18, and select IF BW 27 MHz-C. Call up the file
NULL_27M, adjust the input level–using the variable attenuator–so the null
point is clearly visible, and adjust each null point to the position given by the
markers. See Table 6-3 for the marker number and which coil to adjust.
Table 6-3. Markers and Their Adjustment Coils
Null Point
(Marker Number) Core to Adjust
1 L12 (LF52)
2 L11 (LF51)
4 L14 (LF54)
5 L15 (LF55)
Figure 6-17. Pass Characteristics
Marker Number
▼ 1: 31.75 MHz
▼ 2: 43.75 MHz
▼ 3: 70.00 MHz
▼ 4: 103.00 MHz
▼ 5: 130.00 MHz
▼ 6: 56.50 MHz
▼ 7: 83.50 MHz