20. Last Converter Adjustments
1 0 . 7
N O T C H
F I L T E R A D J U S T
I
R I G H T
I ES
L A S T
C O V E R
C O V E R
C O N V E R T E R
,
3 2 1 . 4 M H z B P F A D J U S T
Figure
Location of Last Converter Adjustments
10. Set the spectrum analyzer LINE switch to ON, and key in
SWEEP
A HET UNLOCK message should
appear on the CRT display.
11. Connect a BNC to SMB snap-on test cable and probe (SMB male
bulkhead connector) to the RF INPUT of the second spectrum
analyzer.
12. Press
on the second spectrum analyzer. Set the controls
of the second spectrum analyzer as follows:
CENTER FREQUENCY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
MHz
FREQUENCY SPAN . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
REFERENCE LEVEL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . -30
13. Press
on the synthesized sweeper, and key in
321.4
MHz,
[
POWER
-20.0
Connect the RF OUTPUT of the
synthesized sweeper to
321.4 MHz IN using a second BNC
to SMB snap-on test cable.
In the following steps, an SMB male bulkhead connector is used as
an input probe for the second spectrum analyzer. The probe tip is
partially inserted through access holes in the bottom cover of the
Last Converter Assembly. If the probe tip is allowed to touch
one of the adjustable capacitors, false readings will result as indicated
by a sudden jump in the amplitude of the 321.4 MHz signal displayed
on the second spectrum analyzer.
14. Partially insert the probe connected to the second spectrum
analyzer into the access hole above
(the second access
hole from the right). Using a non-metallic adjustment tool, adjust
(the right-most of the five access holes) to maximize
the amplitude of the 321.4 MHz signal displayed on the second
spectrum analyzer.
Adjustments 3-17 1