Figure 3-6. Receiving Set, Radio AN/PRR-9, alignment adjustments.

TM 11-6625-937-12

Figure 3-6. Receiving Set, Radio AN/PRR-9, alignment adjustments.

Figure 3-7. Receiving Set, Radio AN/PRR-9, approximate trimmer capacitor settings for alignment.

l. Turn the ID-1189/PR FUNCTION switch to RCVR-FINE RF. Turn the RCVR TEST SIG. rotary switch to its

maximum counter-clockwise position. Place the RCVR OUTPUT plug in the headset jack of the AN/PRR-9 electronic

assembly (fig. 36). Adjust AN/PRR-9 capacitor C1 under hole D for a minimum indication on the meter.

m. Turn the AN/PRR-9 receiver control t OFF and then turn it slowly clockwise to a position equal to one-half of full

rotation, to adjust the receiver for squelch operation. Turn the ID-1189/PR FUNCTION switch to RCVR- SQUELCH.

Leave the RCVR OUTPUT plug in the headset jack. Turn the adjustment screw under hole E fully counterclockwise. Turn

the adjustment screw under hole E clockwise until the meter indication drops to zero; continue to turn the adjustment

screw clockwise an additional one-eighth turn. Turn the FUNCTION switch repeatedly from RCVR-ANT. to RCVR-

SQUELCH and carefully observe the swing of the meter needle. Turn the adjustment screw under hole E until repeated

turning of the FUNCTION switch from RCVR-ANT. to RCVR-SQUELCH produces a rapid swing of the meter needle to

midscale followed by a drop- off to zero. Counterclockwise rotation of the adjustment screw in hole E will increase the

meter swing.

Change 2

3-7