TMA2Q/LPC2Q Tower Mounted Amplifier Instruction Manual
Refer to last page for revision and copyright information, File: TMA2QInstructionManual.doc, Page 14
L
dc
Bias-Tee
C
RF OUT+dc
CCW
RF+dc
RF OUT+dc
CW
RF IN
CW
RF
RF+dc
dc
Bias-Tee
C
TMA2Q Tower-Mounted Amplifier Assy.
ZFBT-282-
1.5A+
ZFBT-282-
1.5A+
SMA-M
SMA-F
SMA-F
SMA-M
SMA-F
SMA-F
SMA-F
RA
N-F
N-F
N-F
RF IN
CCW
L
Top
Bottom
SP-1
SP-1
Bottom
LP1
AD1
VL1
RF
LP2
AD1
VL2
+20 dB
AM1
OUT
IN
+20 dB
AM2
OUT
IN
N-F
210
mm
SMA-F
RA
210
mm
Top
Bottom
N-F
N-F
SMA-M
RA
SMA-M
150 mm
SMA-M
RA
SMA-M
150 mm
VOut
VOut
VIn
VIn
150 mm
150 mm
75 mm
75 mm
Earth
Top
Figure 8 ~ TMA2Q schematic. Power supplies use unmodified SP-1 PCBs
C. LPC2Q LNA Power Coupler Assembly
The LPC2Q components are enclosed in an extruded aluminum enclosure, which is identical in form factor and
size as the Callisto instrument. The internal layout is shown in figure 9 and a schematic is shown in figure 10. The
LPC2Q uses the Mini-Circuits ZFBT-282-1.5A+ bias-tee power coupler modules and a Synergy Microwave DQK-
50-500 quadrature coupler.
The quadrature coupler is a symmetrical 4-port device that provides 90° phase shift on two of the ports. The
coupler introduces 3.5 to 4.5 dB of splitting loss in each transmission circuit. The signals from the two linear
cross-polarized antennas are input to the device from the RF ports of the bias-tees and combined with phase
delays such that circular polarizations are output, one output for right-hand circular polarization (RHP) and the
other for left-hand circular polarization (LHP). For more information on antenna applications of the quadrature
coupler see
http://www.reeve.com/Documents/Articles%20Papers/Reeve_QuadCouplerApp.pdf
and for more
information on radio wave polarization see
http://www.reeve.com/Documents/Articles%20Papers/Reeve_Polarization.pdf
.
In addition to its transmission functions described above, the LPC2Q has provisions for powering the two low
noise amplifiers in the TMA2Q through the bias-tees. This includes two identical 8.0 Vdc power supplies and
associated protection and filtering circuits. The design voltage input range is 11...15 Vdc. Each power supply
output is connected to the dc port of a bias-tee, where it is coupled to the RF + dc port for transmission to the
TMA2Q.
