User's Manual

Digital UHF Transmitter Chapter 5, Detailed Alignment Procedures
DT835A, Rev. 1 5-9
1404) with a frequency determining kit.
These boards operate class AB and have
a gain of approximately 9 dB. The idling
current for each of the transistors is set
to 100 mA digital.
To adjust the idling currents, no RF
applied to the tray, of the devices on
(A5-A2) the amplifier board, connect a
voltage meter across E1 and E2 on the
amplifier protection board and move
switch S1 to the I5 position; adjust R106
for a reading of 1 mV digital. Move switch
S1 to the I4 position and adjust R206 for
a reading of 1 mV digital.
Connect a sweep test signal to J1, the RF
input jack of the UHF amplifier tray. On
(A5-A2) the amplifier board, tune
capacitors C105 and C205 for peak
output power and then tune C119 and
C219 for peak output power with a flat-
frequency response and minimum
current.
To adjust the idling currents, no RF
applied to the tray, of the devices on
(A5-A3) the amplifier board, connect a
voltage meter across E1 and E2 on the
amplifier protection board and move
switch S1 to the I7 position; adjust R106
for a reading of 1 mV digital. Move switch
S1 to the I6 position and adjust R206 for
a reading of 1 mV digital.
Connect a sweep test signal to J1, the RF
input jack of the UHF amplifier tray. On
the (A5-A3) dual stage amplifier board,
tune capacitors C105 and C205 for peak
output power and then tune C119 and
C219 for peak output power with a flat-
frequency response and minimum
current.
To adjust the idling currents, no RF
applied to the tray, of the devices on the
(A5-A4) amplifier board, connect a
voltage meter across E1 and E2 on the
amplifier protection board and move
switch S1 to the I9 position; adjust R106
for a reading of 1 mV digital. Move switch
S1 to the I8 position and adjust R206 for
a reading of 1 mV digital.
Connect a sweep test signal to J1, the RF
input jack of the UHF amplifier tray. On
the (A5-A4) amplifier board, tune
capacitors C105 and C205 for peak
output power and then tune C119 and
C219 for peak output power with a flat-
frequency response and minimum
current.
To adjust the idling currents, no RF
applied to the tray, of the devices on the
(A5-A5) amplifier board, connect a
voltage meter across E1 and E2 on the
amplifier protection board and move
switch S1 to the I11 position; adjust
R106 for a reading of 1 mV digital. Move
switch S1 to the I10 position and adjust
R206 for a reading of 1 mV digital.
Connect a sweep test signal to J1, the RF
input jack of the UHF amplifier tray. On
the (A5-A5) amplifier board, tune
capacitors C105 and C205 for peak
output power and then tune C119 and
C219 for peak output power with a flat-
frequency response and minimum
current.
5.3.9 (A5-A6) 4-Way Combiner
Assembly (1265-1428, low
band/1265-1429, mid band/1265-
1430, high band; Appendix D)
This assembly contains (A5-A6-A1) a 4-
way combiner board. There are no
adjustments to the board.
5.3.10 (A5-A6-A2) Circulator
There are no adjustments to the
circulator.
5.3.11 (A6-A1) Dual Peak Detector
Board, Single Supply (1227-1333;
Appendix D)
The dual peak detector board is mounted
in (A6) a dual peak detector enclosure.
There are no adjustments to the board.