Motorola R-2001D Operator's Manual page 61

RF PRESELECTOR SHAPE & BANDWIDTH
Use this test to insure proper preselector alignment for multi-frequency receivers. Tune the preselector for greater rejec-
tion of an interfering frequency from nearby transmitters.
1. Connect the Analyzer's RF In/Out to the antenna connector of the receiver under test. Connect the Analyzer's
Vert/Sinad/Dist to the RF probe. Connect the probe to the first available low impedance point foHowing the prese-
lector, as shown in figure 4-5.
2. Disable the receiver's mixer injection.
3. Set DISPLAY to Scope DC, FUNCTION to SWP 1-10 MHz with switch in Generate, and Dispr/Sweep control fully
clockwise to 10 MHz.
4. Enter the proper receiver frequency.
5. Set RF Step attenuator to OdB and RF Variable control to mid-range.
6. Use the OSCILLOSCOPE Vertical control to move the horizontaljwee p line to the bottom of the graticule. Set the
Ext V/Div control to 0.01 and its inner knob fully clockwise to C I position.
7. Adjust the RF output level to produce a CRT display at the lowest eadable level to minimize the possibility of over-
loading the circuits being tested.
8. The 3db (.707 of peak) and 6db (.50 of peak) bandwidth points can be checked. Each major horizontal division cor-
responds to 1 MHz with dispersion control fully clockwise and to .1 MHz with dispersion control fully
counterclockwise. The response should be checked for uniformity and symmetry. Tuning adjustments can be made
accordingly.
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