Rev C
7
2. OPERATING INSTRUCTIONS
2.1 GENERAL
The Model 350S1G6A is a self-contained, broadband microwave amplifier designed for laboratory
applications where instantaneous bandwidth, high gain, and moderate power output are required. A
GAIN
control, which is conveniently located on the unit’s front panel, can be used to decrease the amplifier’s gain
by 10 decibels (dB) or more. Solid state technology is used exclusively to offer significant advantages in
reliability and cost. A Model 350S1G6A, used with a frequency-swept signal source, will provide 350 watts
of swept power output from 0.7–6.0 gigahertz (GHz). Typical applications include antenna and component
testing, wattmeter calibration, and electromagnetic interference (EMI) susceptibility testing, as well as usage
as a driver for frequency multipliers and high-power amplifiers. The Model 350S1G6A can be operated
locally by using the unit’s front panel controls, or remotely by using the unit’s IEEE-488, RS-232 interface,
USB, or Ethernet interface.
CAUTION:
The Model 350S1G6A Amplifier is
typically
not critical in regard to source
and load Voltage Standing Wave Ratio (VSWR) and will remain
unconditionally stable with any magnitude and phase of source and load
VSWR.
However, placing the amplifier in the operate mode without a load
connected to the output connector is not recommended
. It has also been
designed to withstand, without damage, RF input power levels up to
twenty (20) times its rated input of 1mW. However, signal levels higher
than 20mW or transients with high peak voltages can damage the
amplifier. Also, accidental connection of the Model 350S1G6A’s output to
its input (either through direct connection or parasitic feedback paths)
will cause oscillations that may permanently damage the unit’s input
transistors.
The 350S1G6A Amplifier is protected from input overdrive by an automatic level control circuit which will
limit the maximum RF level to the first gain stage (U2) of the RF Amplifier to approximately 0 dBm.
NOTE:
The amplifier requires 30 minutes of warm-up time to avoid any gain or power drift.
The 350S1G6A RF power transistors are protected from over temperature by sensing the chassis temperature
near the RF output transistors. In the event of a cooling fan failure or an airflow blockage, the DC voltage will
be removed from the RF stages, when the chassis temperature reaches approximately 70°C.
Normal operation can be resumed after the chassis temperature drops below 70° C.
2.2 CONTROL AND INDICATOR FUNCTIONS
The Model 350S1G6A’s front panel is shown in Figure 2-1; the unit’s rear panel features are detailed in
Figure 2-2.
2.2.1
Keylock Switch
The Keylock Switch is provided for protection from unauthorized use or unexpected remote control of the
amplifier. The amplifier can only be turned on locally when the Keylock Switch is in the
LOCAL
position.
Likewise, the unit can only be turned on or controlled remotely when the Keylock Switch is in the
REMOTE
position. Placing the Keylock Switch in the
INHIBIT
position places the amplifier in the off mode and
prohibits any control of the amplifier.
