4: Technical Description
4-2
MT1099A-MS
A 10-jumper 3-pin jumper block on the amplifier board configures the
MT-1099A for either a PRC1099 or PRC1099/A. It also sets the baud rate for
the RS-232 transmission of data to the antenna tuners.
4.1.2
MT-1099A-24
The MT-1099A-24 operates the same way as the MT-1099A-12 except that it
includes the 28 Vdc M8A switching regulator board that co28 Vdc to
+12 Vdc up to a maximum current of 8A. The MT-1099A-24 provides 24 Vdc
for the RA100-24 while providing 12 Vdc for the antenna tuners and
amplifiers (the RA100-24 uses both 12 Vdc and 24 Vdc).
28 Vdc M8A
Voltage
Regulator Board
The 28 Vdc M8A voltage regulator board includes the MC34063 monolithic
switching regulator U1, configured as a step down voltage regulator. The
M8A also includes the thick film hybrid power output stage SM625, U2, that
consists of a high current Darlington transistor switch with a commutating
diode. The regulator circuit operates at about 75% efficiency and generates
little heat.
Resistors R1, R5 and R6 are current limiting resistors that limit the supply
output to 9A. Capacitor Q10 sets the operating frequency at approximately
50 kHz. Resistor R2 and R3 set the output voltage to 12.6 Vdc. The M8A
regulator circuit is a switching type regulator that uses a pulse width
modulator to control the output. The circuit includes an input LC filter
Figure 4-1. Configuration Jumper Block
Configuration
Jumper Blocks
1
2
3
4
5
6
7
8
9
10
Transceiver
PRC1099A
A
A
A
A
A
PRC1099
B
B
B
B
B
Baud Rate
9600
B
B
4800
B
A
2400
A
B
1200
A
A
JU
1
A
B
1
2
3
4
5
6
7
8
9
10
