Skanti TRP 5000, Инструкция по эксплуатации

Страница: 44 / 112

3.14.2 Band’s A to H
The configuration is basically an L-network, the series inductance of
which consist of may consist of variometer -A-.The rotor and stator of
variometer can be used on the lower frequencies, giving a high value of
inductance. The parallel connection is to be used on the higher
frequencies, giving a lower value of inductance. The transition
frequency depends on the antenna.
The shunt capacitance, in parallel to the P.A. valves, can be selected
between 6 and 1600pF in steps of 6 pF by means of 1 to 9. Increasing
the shunt capacitance while still having resonance (by adjusting the
variometer by means of the tuning knob) decreases the voltage swing on
the P.A. valves ( the load presented to the valves becomes lower) and
vice versa.
If the antenna is long, it may be necessary to use the shortening
capacitors or the output capacitor (wafers 22, 23, and 24 or any
combination of these) in order to obtain resonance. If the antenna is
short, it may be necessary to use the output capacitor (wafer 24) on
the lowest frequencies.
The configuration is basically, a 27-network. The series inductance may
consist of either variometer –A- or variometer -B-. The rotor and
stator of variometer -B- may be connected either in series or in
parallel. The parallel connection is to be used only in the higher
frequency bands. The transition frequency depends on the
antenna.
The shunt capacitance, in parallel to the P. A. valves, is pre-set on
each band by means of wafers 13, 14, end 15.
The output capacitance can be selected between 6 and 1600 pF by means
of wafers 1 to 9. increasing the output capacitance, while still having
resonance, increases the voltage swing on the P. A. valves
and vice
versa.
On frequencies above 8 MHz the output capacitance can be reduced, it
necessary, by means of the coils at wafers 24 and 25. The coil at after
24 is to be used only on the 22 MHz and 25 MHz band’s, where the
impedance of the series connected capacitor, is negligible.
Due to un-avoidable stray capacitance’s, resonance in variometer –A-
can occur on one or more of the short wave band’s. It shows up as a
sudden dip in the ANTENNA CURRENT meter-reading when the TUNING control
is rotated slowly over its range. Such resonance’s within a band must
be avoided as they can cause flash-over. This is avoided by showing
variometer -A- of the band in question by inserting tabs in wafers 27
or 17 and 19 or all three.
3.14.4 Adjustment Procedure:
3.14.4.1 1.Set SUPPLY switch to STAND BY and POWER switch to MEDIUM POWER
SIMPLEX
.
2. Insert tabs for the band in question as shown on Pages 3-28 to 3-32.
3. Set SUPPLY switch to TRANSMIT and press TUNE button while rotating
the TUMNG control until resonance is obtained, i.e. maximum
deflection on ANTENNA CURRENT meter without being at the extreme of
the tuning range (inspect rotor position of the variometer used).
3 - 18