Circuit Description; Remote Sensor; Switching Circuits - Heathkit HM-2140 Manual

Refer to the fold-in Schematic Diagram
description.
A bare wire connects input jack J101 to output jack J102 through
L1010 L1o1 is a current pickup
power which passes through the remote sensor. A transmitted
sing through the sensor induces a voltage in the toroid coil which is directly
proportional to the RF current.
mission line is summed with the voltage at L101. The sum of the voltages is
then rectified by diode D102 and is filtered by capacitor
factory calibrated to within 5% accuracy
watt circuit and by control R1o? for the 0-200-watt
The "out-of-phase" (reflected) current-induced
with the sampled voltage is rectified
capacitor C101. With a very good load, that is one with less than 1.05: 1
VSWR, the two voltages will be about
reflected voltage would appear in the reflected
factory calibrated by control R104 for the 0-50-watt
the 0-500-watt scale.
The calibrated voltages from the remote sensor are routed through
cable to the input circuits of the switch
as you read the following
element for both the forward and reflected
signal pas-
A voltage sampled directly from the trans-
C104. The sensor is
by control R106 for the 0-2000-
circuit.
voltage that was summed
by diode D1o1 and filtered
equal and out of phase
circuits. Reflected
scale and by R105 for
circuit board.
Tie
circuit I\lPORT_\"'\l'
seale-d: ·.:c:c.,,· •..tiorize-d
ranty your V_-2tt:rrleter.
0:::'
toroid coil
'Tie
C\'OTI: :J:-.''-iOI'::and reflected
\'irtually :de::.::cc:.. I::. me fDllowing discussion,
tion of the rDrwiOId circuits.
operation DI me
The Ionmrd signal
board and is roc:te-d tc.."=i~gb.LOW-HIGH switch SW1. If the output
transmitter is known te De less than 200 watts, switch SW1 should be set to
the LOlr (in; pos:GCI:.
should be set to HIGi-l =-':':.
by
Signals from S\ \'1 are cu-':':i'"dd:rectly to SET-FWD switch SW4. When SW4
is in the SET lin ;Jos:t:o::'. :'::.eforward rFWD) meter is temporarily
and no
nected from the circe::. T::e low-current
power is
directly through
S\VR-REF s\\-itch S\\'3.
tion with S\\'3 when SW3
(reflected) meter "Set" :.':ldex is used to calibrate
a 5-wire
ings.
remote sensor is factory aligned,
tampering with the remote sensor can void the War-
circuits on the switch circuit board are
we will explain the opera-
Where differences
circuits. further details will be supplied.
t'SG
:he remote sensor is coupled
=C:TI
=i
tl::e power is greater than 200 watts, switch SWl
input from the sensor is coupled
S\\·.;. tirT-=.gi Sensiti-.-ity control
Tie
SET ;Josition of sIr ..•is used only in conjunc-
:5
:n the S\\~ position.
calibrated, and is
exist between the basic
to the switch circuit
of the
discon
R1 to the contacts
0
At that time, the REF
the meter for SWR read-