SG-2000 MANUAL
179
The SGC Building, 13737 S.E. 26th St. Bellevue, WA. 98005 USA
©1995, SGC, Inc.
TEL: (206) 746-6310 FAX: (206) 746-6384
Connect Power Supply (PS-35) 13.6V to J12 + and J14 -.
Turn Power Supply on, 13.6V indicator on Test Box should come on.
Turn Test Box Power switch on, 10V indicator should come on.
From Test Box Filter Band Select Knob (SW2), select each filter (A through F) by
moving Knob from position 6 to 1.
The Spectrum Analyzer should display the bandpass of the corresponding
filter. Compare the Analyzer value with the value of the corresponding filter in
the Filter Band Table above. Results should be within ±10%.
Momentarily flip the LPA to transmit (SW1 flip to XMT) and observe the curve
on the Analyzer. It should show an interrupted circuit.
Disconnect the Analyzer and Tracking Generator.
Turn Power Supply off
23.2.6
Transmit Alignment
Disconnect Spectrum Analyzer and Tracking Generator.
Connect LPA RF Out to a 250 W wattmeter and then to a 50 ? dummy load
antenna (= 30 dB attenuator). The output of the attenuator goes to the scope.
Select any filter on the LPA from the Test Box.
Check that F2 and F3 are not installed. Turn power supply on and apply
voltage to the LPA.
Switch to transmit and check the following voltages:
•
collector of Q1 = 13.6 V (in transmit only)
•
collector of Q2 and Q3 = 13.6 V (in transmit and receive)
•
base of Q1 = 1.9 V, adjustable from R2
•
emitter of Q1 = 1.2 V
•
base of Q2 and Q3 = .70 VDC, adjustable from R32
•
base of Q6, Q7, Q10 and Q11 = .67 VDC adjustable from R20 and R28
Turn power supply off and connect 20 A amp meters in the place of F1 and F2.
Select Filter A (6 on dial)
Connect RF Generator to RF In (J1) on LPA with 0 dB, 1.6 MHz RF Out.
Switch to transmit and watch for:
•
current on Power Supply should never go higher than 32 A for 150 W RF
Out
•
the twin current meters should not differ by more than 4 A. Use R20 and
R28 to bring them to = 2 A difference.