R.V.R. Elettronica PJRL250, Техническое руководство

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PJRL250 Technical and Maintenance Manual
R.V.R. Elettronica S.r.l. (Bo) Pag. 10
SECTION 1
PJRL250 DESCRIPTION
1.1 EXTERNAL DESCRIPTION
The PJRL250 is housed in a 3U 19" rack completely assembled with modules
fitted on main rails, wired with connectors allowing easy servicing and
replacement.
On the front panel the alarm indicators, the mains switch and the meter for
the principal parameters.
On the rear panel the RF INPUT and RF OUTPUT connectors are located, together
with the telemetry connector, the RF output test connector (directional
coupler), the mains socket the fuses and an auxiliary mains line output for
the supply of other exciters of a different design and make.
1.2 ELECTRICAL DESCRIPTION
PJRL250 is a MOSFET power amplifier working on the 215-225MHz band with
an output power in excess of 250W and a drive level of about 10-12W.
This amplifier uses one RF module able to deliver more than 250W, with switching
power supplies for high efficiency.
A built in low pass filter suppresses the harmonic content below the FCC and
CCIR requirements.
A protection system takes care of the amplifier against thermal problems,
excessive input drive power and excessive SWR inside the amplifier or along
the feeder. This system provides an automatic reset to initial conditions when
the problem ceases.
1.3 METERS AND INDICATORS
The principal parameters of the amplifier are read by the analog multimeter
(9 Fig.1) and selected by the rotary switch (8 Fig.1) on the front panel.
Various led indicators indicate the alarm conditions (7 Fig.1).
The push-button (3 Fig.1) resets the counting circuit of the protection
circuit.
An indicator confirms the presence of the mains voltage (5 Fig.1).
The ON led (2 Fig.1) indicates the amplifier is working, EXT. ST.BY led (1
Fig.1) indicates an external lock and a wait state of the amplifier.
1.4 AUTOMATIC LEVEL CONTROL
An unused characteristic of this amplifier is the outstanding power gain;
indeed without preamplifiers we have an output power of 250W with a drive of
only 10-12W.
A power limiter stabilizes the output power against input drive fluctuations.