Hy-Gain 480, Инструкция по установке и эксплуатации

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To provide for the extra power contained in the AM signal
modulation it is necessary to "over-couple" the output
circuit. This is necessary to insure an undistorted out-
put with a minimum of adjacent channel "bleeding': (Spatter)
Reapply drive power and advance the load control unti I the
red visual output indicator dims perceptably, ( about 15
per cent more rotation). Readjust the tune control for max-
imum output. The output circuit is now "over-coupled".
If a relative power output indicator is available (SWRbridge
on forward, etc.) the output signal can be quickly checked
to Insure upward modulation. If the meter does not "flick"
upward on ~oic~ peaks, the load control is improperly set,
(or the exciter
IS
not capable of 100 per cent modulation
or may have "downward modulation"). .
Automatic antenna change over and ampl ifier operation is
provided for by a special transistorized input sensing cir-
cuit. Should you desire to hold the amplifier ina "ready"
condition, but not use it unti I needed, simply place the
Stby-Oper Switch in the Stby position. The sensing circuit
will be disabled and the antenna connected to the exciter
(transceiver) at all times.
The amplifier is tuned for FM service in a manner identical to AM
(""". exceptthe load and tune controis are set for maximum output.
No change in brilliance of the output indicator will be noted with
modulation.
Place the function switch in the SSB position. This will connect a
delay circuit to the automatic relay control and extend the
"drop-out" approximately one second. This will prevent relay
"chattering" and erratic operation.
If the exciter (transceiver) is capable of carrier output equal to
the peak power of the voice SSB or DSB signal, simp:y adjust the
tune and load controls for
maximum brilliance of the output
indicator while applying carrier.
If the exciter (transceiver) cannot supply a carrier equal to the
peak power of the voice SSB or DSB signal then the tune and
load controls must be set for maximum output while modulating.
In this case, a modulation envelope indicator (monitor scope) is
the mo!?treliable method for adjustment of the amplifier.
Place the function switch in the SSB position, apply drive power
and adjust the tune and load controls for maximum output.
The delay circuit for SSB prevents "drop-out" of the automatic
antenna relay between characters.
Remove knobs and replace controls cover before putting the
Amplifier into business radio service.
For operation on the six meter amateur band is necessary to short
out three turns (from the left hand side asviewed from the front
panel) of the Pi-network output coil, L 1. The 100 pf silver mica
capacitor
across C8, (load capacitor-) must be removed. C17
should be reduced to 5pf also.
,The low pass fi Iter on the output must be shorted out. This
can be done by soldering a wire from the input to the output
and removing the three silver mica capacitors (180pF and
240pF) from the small circuit board connected to the output
socket.
REMOVE FOR 8 Mt.nR
AMATEUR BAND
OPERATION
IOOpf CAPACITOR
ACCROSS e-8
A portion of the incoming signal is coupled to the base of 02,
sensing transistor. This causes02 to conduct and change the !:lias
on 01, relay transistor, 01 conducts heavily and closes relay K 1.
Relay K1 connects the input signal to the cathodes of V1 and V2,
applies plate voltage to V1 and V2, and connects the output
circuit to the antenna.
C9 is the Pi-net tune capacitor. sets the operating frequency to
the antenna.
C8 is the Pi-net load capacitor and controls the coupling to the
antenna.
For SSB operation, C14 is added to the relay transistor circuit to
extend the "drop out" time.