The PA-2224 4-kW high-efficiency class AB HF power amplifier features the linearity of a class A design and the efficiency of a class AB design. This modular designed unit uses silicon DMOS devices in its 300-W power modules. Four power modules are combined to provide a 1-kW rack-mountable "drawer." The cabinet consists of a controller, four 1-kW drawers, a 4-way RF combiner, and a power supply unit. The power amplifier is capable of providing 4-kW PEP and average continuous output. A microprocessor monitors "housekeeping" functions such as voltage, current, and temperature sensing, and forward and reflected power. A multirange low-pass filter suppresses harmonics.

The PA-2224 4-kW Power Amplifier System is comprised of four 1-kW PA modules (PA-2220A), a 3-phase power supply module (PS-2224), a 4-way Combiner module (CM-2224) and a system Controller Module (SC-2224). The modules are enclosed in a standard EIA 19" cabinet.

The 4-kW PA-2224 is a member of the URG-III product line family of HF communications equipment and is designed for use with the RT-2200 Receiver-Exciter.

• 4-kW continuous RF output power, PEP or average
• 1.6 to 29.99999 MHz continuous frequency coverage
• Automatic Level Control (ALC) maintains maximum "talk power"
• Full output power delivered into VSWR of up to 1.3:1
• Operates into VSWR of up to 3:1 with automatic, gradual, reduction of output power
• Fully protected when VSWR exceeds 3:1
• Modular Design
• DMOS output stages ensure linear, highly efficient, operation
• Multi-range low-pass filter ensures RF output signal purity
• Built-in metering of forward and reflected operating power levels
• Over-temperature and VSWR fault conditions are monitored
• Built-in Test (BIT) routines quickly isolate any operating problems
• Standard 19-inch cabinet serves as a mount for all sub-units of the power amplifier
• Controlled and monitored via standard EIA data bus from the RT-2200
• Capable of operating at temperatures up to 50 degrees C
• Internal blowers ensure proper cooling of the entire assembly

A block diagram of the PA-2224 is shown below. An input signal splitter drives four identical PA-2220A 1-kW RF amplifier "modules." The four RF power modules are combined to provide a full 4kW PEP and average continuous output.

The control card uses a microprocessor to manage several tasks including the serial control interface, internal "housekeeping" functions, and built-in test.

The control card provides selectable EIA-232/485/422 serial interfaces for an external exciter. Critical internal parameters such as voltage, current, and temperature sensing, and forward and reflected power are sampled for the control card. The microprocessor uses these digitized samples to continuously monitor the status of the power amplifier and for diagnostics during built-in test. Parameter values, status, and built-in test results are reported to the exciter over the serial interface.

The PA-2220A includes:

• Instruction Manual

Product Information Material is normally available at no charge and can be obtained by contacting GS Customer Relations:

Phone: 800-321-2223 or 319-295-5100

Fax: 319-295-4777