Codan NGT 2010 RF Technical & Service Manual page 546

High power—Technical description
Transmit path
High-power PA & Antenna Control PCB
Drawing
This unit provides the control interface between the NGT, the power amplifier and the
SG235C antenna tuner. The NGT antenna control output is reconfigured to supply clock,
data and PTT information to the antenna controller.
When the frequency band of the PA changes, the NGT sends data via the clock and data
lines to the microprocessor IC3. IC3 decodes the data and drives IC4 to select one of the
seven PA bands on J2. Switch S1 is read by IC3 and is used to set up the system for
different external PA types.
Table 14: Position of digi switch S1
Digi switch
position
0
1
2–15
The PTT signal is connected to the PA via IC2/A/B V5 and V7. The microprocessor IC3
can disable the PTT by switching V6 on.
When the SG235C antenna tuner is connected to the system at J1, the tuner reset line is
driven low when the NGT is scanning. IC3 also drives the
indications on the
232
04-03377
Mode
Datron TW500A/TW1000A
Datron TW500D/TW1000D
Undefined
NGT).
Frequency range to band selection
Band1 Not used
Band2 0 ≤ f < 3 MHz
Band3 3 ≤ f < 5 MHz
Band4 5 ≤ f < 8 MHz
Band5 8 ≤ f < 13 MHz
Band6 13 ≤ f < 20 MHz
Band7 f ≥ 20 MHz
Band1 Not used
Band2 1.6 ≤ f < 3 MHz
Band3 3 ≤ f < 5 MHz
Band4 5 ≤ f < 8 MHz
Band5 8 ≤ f < 13 MHz
Band6 13 ≤ f < 20 MHz
Band7 f ≥ 20 MHz
Future use
LED (see
NGT Transceiver System Technical Service Manual
page 226, LED