Page 36
The regeneration control on the rear chassis
apron should be sufficiently advanced in the
clockwise direction to cause the detector to
go into regeneration. This is indicated by a
distinct "hissing" or "rushing" sound. If the
detector should drop out of oscillation and
remain so during alignment, it will be neces-
sary to advance the control further.
Connect the signal generator set to 146 mc to
the antenna input. If the genera for has clip
leads,
connect
the
generator
shield or
ground lead to the rear apron ground post.
Connect the "hot" lead to the wire running
between the TRANSMIT -RECEIVE switch
and the antenna jack. If a grid dipper should
be employed, set the frequency to 146 mc
and position the dipper coil so that for initial
alignment it is approximately 6" from the
receiver. At this distance, radiation from a
dipper used in the CW (carrier on) condition
should be sufficient for calibration pur-
poses.
With the receiver operating, set the tuning
knob pointer vertical (146 mc) and adjust the
detector coil L6 to receive the signal. This
is indicated by maximum quieting in the
receiver. This adjustment should be within
several turns of its preset position.
Now rotate the receiver tuning capacitor
knob from one extreme to the other, making
certain the detector remains in regeneration
at both extremes. Also make sure that the
received signal (from generator or grid
dipper) is centered at the 146 mc point.
Leave the generator frequency set at 146 mc
and decrease the generator output to the
point where the signal is just barely receiv-
able. This
will be in the vicinity of
1
microvolt fundamental frequency on a cali-
brated generator. Now adjust the antenna
coil L5 for maximum gain of the RF ampli-
fier, as indicated by maximum quieting in the
detector. This adjustment may change the
frequency of the detector
slightly, so it
should be checked and retuned if necessary.
The proper setting of this coil will be within
several turns of the preset position. The
peak will be rather broad in nature, al-
though a definite increase in gain will be
noted as the coil is tuned near 146 mc
resonance.
) Recheck the adjustments of the detector coil
L6 for calibration, the antenna coil L5 for
gain and the regeneration control Rh for
maximum sensitivity. With the two coils
properly adjusted, set the regeneration con-
trol to the minimum clockwise position, at
which the receiver will remain in regen-
eration over the entire tuning range and
always start when the unit is turned on.
METHOD 2 - AN -ON -THE -AIR SIGNAL
) With a
suitable
antenna connected (see
antenna section, Page 37), have a friend,
preferably at a distance of 10 miles or so,
(depending upon his station equipment and
your antenna) transmit a test signal for you.
(
) Set the receive tuning knob to indicate his
approximate known frequency. Now adjust
the detector coil L6 to receive his signal.
This adjustment should be within several
turns of the preset position.
After dial calibration has been established,
adjust the antenna coil L5 and the rear
apron regeneration control R11 for maxi-
mum sensitivity of the receiver. This is best
indicated by maximum quieting rather than
loudest signal since the detector provides
effective automatic volume control action
above 3 microvolt input. If the on -the -air
signal produces complete quieting, attempt
to reduce the signal input to the receiver, by
rotating either antenna system. Final ad-
justment of the receiver should be done
with a very weak signal, one just barely
audible. Simultaneously adjust L5 for cali-
bration and L6 and R11 for sensitivity.
Some readjustment of the transmitter final
tank capacitor, C16, will normally be re-
quired when the transceiver is loaded into a
typical
antenna system, after which the
cabinet may be installed and secured with
four 6-32 x 3/8" screws. This final adjust-
ment of C16 is for maximum voltage on the
transmission line indicated on an external
DC voltmeter plugged into the first position
of the meter jack. For a properly matched
antenna and transmission line, maximum
voltage indicates maximum power output.
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