TM 11-6625-2718-14&P
c. When the TS-2609A/U is connected into the
from the 10-watt reflected reading sensing circuit
system, transmitter output is directed through
is applied to the meter. In the 100 RFL position,
the line section to the antenna (or dummy load).
the selector switch connects the meter to the 100-
The line section is a short, uniform section that
watt output of the reverse reading sensing unit.
provides unimpaired impedance of the rf coaxial
f. To compensate for changes in surrounding
line into which it is inserted, The rf waves
temperature, a temperature-correction circuit is
traveling through the line section produce energy
provided. This circuit consists of thermistor R10
in the coupling circuits of both sensing units by
and fixed resistor R9 connected in series and
inductance and capacitance. Inductor L2 and
placed across the meter. The fixed resistor is
capacitor C8 sense forward power, while inductor
matched to the thermistor to provide the tem-
L 1 and capacitor C7 sense reflected power.
perature correction required.
Whether the meter is being used to sense the
g. Resistors R1 and R2 limit the loading effect
forward or the reflected power is determined by
of inductors L1 and L2 respectively on the trans-
the position of selector switch S1.
mission line, provide broadband, impedance
d. The output of the coupling circuit is applied
circuits, and develop the voltages coupled to rf
to a resistive and capacitive network which has
rectifiers- CR1 and CR2 for measuring reflected
been carefully balanced to its associated coupler.
and forward traveling signal power levels. The
Each sensing unit will provide a current output
rectified signals are filtered by C2, C4, C6, R4,
that will cause meter M1 to deflect in proportion
a n d R6 for forward traveling signal power
to the rf power applied to the line section,
measurements below the 10-watt level, and Cl,
provided the frequency of transmission is within
C3, C5, R3, and R5 filter the rectified signals for
the rated range of the TS-2609A/U.
reflected traveling signals power below 10 watts
c. Each sensing unit has two forward and two
when the selector switch is set to the 10 RFL
reflected power ranges. One forward range will
position. When the selector switch is set to the
deflect the meter 100 watts when 100 watts is
100 FWD position, multiplier resistor R8 is added
applied to the transmitter end of the line section.
to the forward traveling power filter circuit and,
The other forward range will deflect the meter 10
when the selector switch is set at 100 RFL,
watts full scale when 10 watts is applied to the
multiplier resistor R7 is added to the reflected
transmitter end of the line section, When selector
traveling power filter circuit.
switch S1 is placed in the 10 RFL position, output
5-2
