Microwave Converter | Model 11793A |
RF Devices (Service Sheets 1 and 2)
Because of the diversity of test equipment and techniques available for troubleshooting the
| Table 10. Performance Parameters |
Device | Performance Parameters to Check |
AT1 | Attenuation: 2.5 to 3.5 dB at 18 GHz |
3 dB | 2.0 to 4.0 dB at 26.5 GHz |
Attenuator | SWR: 4.251 at 26.5 GHz~~ |
FL1 | 3 dB Corner: 900 to 1100 MHz |
Passband Insertion Loss: <0.25 dB at | |
Filter |
|
~~
800MHz
s1, s2 Insertion Loss: 4 . 5 dB at 26.5 GHz
Switch SWR: <2.0:1 at 26.5 GHz
u1 Frequency Range: 18 to 26.5 GHz
LOGain: >11 dB
Amplifier SWR: C2.51
u2 Frequency Range: 10 to 700 MHz
IF Gain: 14 dB
Amplifier SWR: <1.8:1
u3 LO Frequency Range: 2 to 26.5GHz
Mixer RF Frequency Range: 1.3 to 26.5 GHz LO Power: >+8 dBm
Conversion Loss: <lo dB
SWR: <4:1
Control Devices (Service Sheet 3)
Set a power supply to 0 Vdc and connect it to the FREQ OFFSET INPUT connector. Set the supply to 0, +3, and +S Vdc respectively, and compare the logic levels of the logic devices with those listed in Table 9. When specifically checking the drive transistors 42, Q3,Q4, or QS, note the following:
The switch solenoids automatically disconnect after completion of switching. Therefore, it is difficult to distinguish between a drive transistor that is on but not drawing current, or one that is off and not drawing current. The collector voltages will differ by only a few mV. If any of the transistors are known to be working, compare the on and off voltages of the suspected transistor against those of a known good one.
Power Supplies (Service Sheet 3)
Check the points indicated in the schematic diagram for dc level and ac ripple. Note that the +SV Regulator is dependent on the +12V Regulator.
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