User's Manual

TXRX Systems Inc. Manual 7-9408-1.2 07/25/05 Page 29
61-38-05 UserMan page 29 of 38
forming a multi-section subassembly. This proce-
dure requires the following equipment:
1) IFR A-7550 Spectrum Analyzer / Tracking Gen-
erator combination.
2) Eagle RLB150N3 Return Loss Bridge or equiv-
alent (35 dB directivity).
3) Double shielded coaxial cable test leads
(RG142 B\U or RG223/U).
4) 50 Ohm load with at least -35 dB return loss
(1.10:1 VSWR). JFW Industries model 50T-007
or equivalent.
5) Regulated DC power supply at the required
voltage.
6) Insulated metal blade tuning tool for adjusting
ceramic and/or piston variable capacitors.
Similar equipment from other manufacturers
should yield acceptable results.
ADJUSTMENT PROCEDURE
1) Set the tracking generator output level to -20
dBm, the desired center frequency and sweep
width of 20 MHz.
2) Connect the test lead together through a female
barrel connector to obtain a zero dB reference
level. On the IFR A-7550 proceed as follows:
a) Make sure that the unit is in "LIVE" mode
when performing step 2.
b) From the Mode Menu, "STORE" the above
trace.
c) Switch to the Display Menu and select "REF".
A display with a vertically centered trace should
be visible.
3) Connect the equipment as shown in
Figure 21
.
4) Remove the amplifier top cover. Engage the
Output Tuning Capacitors one at a time and
rotate them for maximum gain.
Figure 20
: Mechanical layout of a single section amplifier subassembly.
Bias Regulator
Circuit Board
Output Tuning
Capacitors
RF Board
Input Tuning
Capacitors