Page 72
)
Tune your exciter for full
CW
output at the desired
J
frequency. The MU LTI-METER on the Amplfiier,
when switched to indicate REL. PWR., will show the
relative, power output of the exciter and may be used
,
even though the Amplifier
is
off.
(4)
Reduce the exciter output to 0 by placing
its
controls
in the receive mode; also turn
its
MICICW Level
/
control fully counterclockwise.
(
\I)
Turn the Amplifier on.
(Jf
Place the exciter in the tune mode. The amplifier plate
meter should read approximately .12 ampere resting
plate current. Then advance the Level control until the
PLATE METER shows .3 ampere.
(4)
Peak (adjust) the amplifier TUNE and LOAD controls
,
for maximum REL. PWR. meter indication.
Advance the drive to
.4
ampere plate current and
repeak the TUNE and LOAD controls. The Meter
readings should then be approximately:
Plate amperes
=
.35
High voltage
=
2100
Grid mA
=
110
(J)
Alternately adjust the TUNE, LOAD, and exciter drive
controls for the desired input. Refer to Figure 3-4.
The meter readings at 1 kw2 input will be.
approximately:
Plate amperes
=
.5
-----
High voltage
=
2000
d'
Grid mA
=
100-200
_..-
---
I
J)
Advance the SENSITIVITY control for the desired
RE L. PWR. meter reading.
200 .300 .400
.
500 .600 .lo0
PLATE AMPERES
Figure
3-4
(d
Turn the exciter Mode witch to Standby or the
desired transmission mode..
The Linear Amplifier
is
now loaded for operation on CW or
RTTY. If an oscilloscope
is
being used for monitoring, a
display similar to that shown in Figure 3-5 should
be
obtained. If you have a Heathkit Model 610 Monitor Scope,
you may find that
its
optional trapezoid display pattern
is
more easily interpreted for voice patterns.
CAUTION: While actually transmitting, DO NOT switch
between CW/TUN E and SSB modes.
SSB
PROCEDURE
/
(
Jl
Tune up the exciter and Amplifier as for CW
operation. NOTE: In the absence of the recommended
oscilloscope monitor, either the PLATE METER or
the REL. PWR. indication can be used to monitor
SSB
transmission. The PLATE METER indications are
easier to follow.
Low Power
SSB
(d
For 1000
-..-
watts
----
P.E.P. operation, switch the exciter
only
to the SSB mode. Leave the amplifier MODE
switch at CWRUNE.
(4
Adjust the exciter drive control so the PLATE
METER will indicate between .Encampere with
average speech. Hard voice peaks should not excsd
.250 ampere.
--
High Power
SSB
(
For 2000 watts P.E.P. operation, switch both the
-
exciter and the amplifier MODE switch to
SSB.
(
)
Advance the exciter drive level until the PLATE
METER reads from .2 to .3 ampere with average
speech and no higher than .33 ampere on hard voice
peaks. A higher drive level will cause "flat topping."
An
example of
a
proper SSB oscilloscope pattern
is
shown in
Figure 3-6. Note that there are sharp, distinct peaks. The
number of patterns or "christmas trees" will depend upon
the operator's voice characteristics and the scope sweep
speed. Set the scope for approximately 30
Hz
sweep.
Note that the meter reading on voice peaks will not be high,
due to meter inertia and voice characteristics; however, the
height of the oscilloscope pattern
is
greater than that shown
in Figure 3-5.
Figure 3-7 shows the same voice pattern but with extreme
"flat topping." The oscilloscope shows that
no
more useful
.
power
is
being developed. When the drive level
is
too high
the meter reads higher, but only distortion
is
developed.
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