PA-2220A: 1-kW Power Amplifier

The PA-2220A consists of two major assemblies, the RF amplifier itself and its companion power supply). The two units together form a 1-kW high-efficiency class AB HF power amplifier, a design that features the linearity of a class A amplifier combined with the efficiency of class AB. It delivers 1-kW RF, PEP and average, into a 1.3:1 VSWR load over the frequency range of 1.6 to 29.99999 MHz. The amplifier unit receives its operating voltages from the power supply, while the combination is available for operation from 230 VAC single phase.

The 1-kW PA-2220A is a member of the URG-III product line family of HF communications equipment. It is designed for use with the RT-2200 Digital Signal Processing Receiver-Exciter.

Modular Design	Operates into VSWR up to 3:1 with graceful power degradation
1000 Watt PEP & average	VSWR Protection above 3:1
1.6-29.99999 MHz Operation	19-inch Rack Mountable
Automatic Level Control (ALC)	Companion AC Power Supply
Built-in Test (BIT) Routines	Multi-range Low-pass Filter
EIA-232/485/422 Interfaces	Compatible with URG-III product line

A block diagram of the PA-2220A is shown. An input signal splitter drives four identical 300-W RF amplifier modules. The RF amplifier module is designed with silicon DMOS devices which give the power amplifier its high efficiency and linearity. The four RF power modules are combined to provide a full 1-kW PEP and average continuous output. An 8-band low-pass filter suppresses harmonics.

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.

Parameter	Performance
Electrical
Frequency range	1.6 to 29.99999 MHz
RF Power Input	100 milliwatts nominal
RF Power Output	1-kW (+/- 0.5 dB) PEP and average into 1.3:1 VSWR
VSWR Turndown	Operates at reduced power into 1.3:1 to 3:1 VSWR. Stable at any load. Protected for infinite VSWR
Input Impedance	50 ohms nominal, 1.5:1 VSWR max
Gain Variation	2 dB max over frequency range
Harmonic Levels	-63 dBc or better into 50-ohm load
3rd order IMD	> 36 dB below PEP
RF Noise	Better than 75 dBc/Hz below full rated power
Spurious Emissions	-60 dBc or better at up to +/-5 percent from operating frequency -80 dBc or better at greater than +/-5 percent from f0
Frequency Change Time	50 ms max between any two frequencies
Key Control Time	RF power is within +/- 1 dB of steady state level in <10 ms after key ON. RF power is reduced by more than 50 dB ~5 ms after key OFF
Operating mode	Class AB
Prime Power	230 V ac 1-phase approximately 3500 watts
Control	EIA-232/485/422 serial bus, ALC (to external exciter) & BIT parameters via serial bus
Environmental
Temperature, Operating	0 to +50 C at mean sea level, derated linearly to -20 C at 10,000 feet above mean sea level
Temperature, Non-operating	-40 to +60 C
Humidity	0 to 95 percent, non-condensing
Altitude	operating, 0 to 3050 meters non-operating, 0 to 15250 meters
Cooling	forced air, internal fans
Acoustic Noise	55 dBa
Physical
Front Panel Indicators	VSWR fault Over-temperature fault
PA-2220A	Height: 10.5 inches (267 mm) Width: 19.0 inches (483 mm) Depth: 22.0 inches (559 mm) Weight: 65 pounds (30 kilograms)
PS-2220A	Height: 7.0 inches (178 mm) Width: 19.0 inches (483 mm) Depth: 19.5 inches (489 mm) Weight: 40 pounds (18 kilograms)

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