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rent in conjunction with 20K of output power.
again,
check
the driver p1-7.te circuit for resonance by adjusting control on
the driver panel marked " plate tuning".
Át this tiYle a check of the match between the driver and the
amplifier grid should be made.
The grid tuning control C618
and
0619 should be adjusted for ::laximum grid current and the
grid loading control 0620 adjusted so that :2aximum grid cur-
rent and uinimum VSWR occur simultaneously.
Á VSdR of 1.1-1.4
is normal.
The transmitter should now be operating normally.
Each installation has different conditions where the Trans-
iuitter works best because of transmission line and antenna
characteristics.
Á careful trim:ling of the amplifier should
be made.
These are the conditions which should be strived to
achieve:
1.
Minimum drive to the driver and amplifier grid
for a given output power.
o
6
2.
Plate circuits tuned to resonance, ( Tetrodes which
are heavily loaded,
a plate current dip is very
slight).
3.
Plate and screen dissiption at a minimum for a given
power output.
4.
Operation of amplifier with as much fixed bias as
necessary without reducing the power eut)ut or ex-
cessive drive reçuirements for a given operating
point.
5.
Output loading control triaàed for maximum loading
conditions.
6.
Minimum VSWR between driver and amplifier.
If a reduction in power output is desired this can be done by
lowering the screen voltage and reducing the drive.
The amp-
6/22/61
-12-
FM- 20B
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