R.V.R. Elettronica PJ300M, User Manual, Page: 26 / 34

PJ300M
20 / 28 User Manual Rev. 7.0 - 25/07/03
8.2 R.F. Power Amplifier
The RF power amplifier section is composed of a single power module hosted in a
shielded enclosure of the amplifier. The module is mounted on a heat sink that allows
its cooling through forced ventilation.
The module is supplied separately by the switching mode power supply, and delivers
300 W of RF power with approx. 8 W of input.
The quiescent parameters of the module are:
Vdc = 50V, Vgs = 3.5 V, Idq = 200 mA
The active device employed is a power MOSFET (BLF278).
8.3 Low Pass Filter
The filter attenuates the spurious emissions of the amplifier under the levels allowed
by the international standards, so that the amplifier can normally be directly connected
to the transmission antenna.
Thanks to this low pass filter the amplifier features a harmonic suppression of more
than 75 dB.
8.4 Alarms Card
This card detects any system anomaly such as excessive internal SWR external
SWR, overheating, etc. This module will also, whenever possible, reset the system
to its original condition, after a fault happened, as described in the previous chapters.