Note
The TE Systems Model 0552 and Model 0552G are solid-state, high-power linear power amplifiers. Manufactured by TE Systems (Los Angeles, California), these units are optimized for operations in the VHF frequency range, specifically the 50–54 MHz amateur band.
The primary distinction between the two models is that the 0552G includes an integrated low-noise receive preamplifier, whereas the base 0552 operates solely as a transmit power amplifier.
Model Overview & Key Differences
Model 0552: A high-power linear RF amplifier designed strictly to amplify the transceiver's output signal during transmission. When receiving, it defaults to a straight-through coaxial bypass configuration.
Model 0552G: A complete RF amplifier subsystem that integrates the same high-power transmit stage with a factory-installed, high-performance GaAs FET low-noise receive preamplifier (LNA). This configuration provides both boosted transmission power and highly sensitive weak-signal reception capability.
Mode Control: A rear-panel adjustable potentiometer allows operators to alter the relay dropout delay time. This feature is particularly useful for changing modes from FM (which requires immediate drop-back) to SSB/CW (which benefits from a longer delay to prevent relay "chatter" during speech pauses or code breaks).
Remote Accessory Port: A dedicated rear connector socket allows operators to run extended configurations. Through this interface, you can hard-wire a direct PTT Line (bypassing the RF sensor for faster hard-keyed setups), remotely toggle the amplifier and preamplifier on/off, and even disable front-panel LED illumination to conserve battery drain in remote or trunk-mounted installations.
Thermal Shutdown Protection: Due to the dense heat generated by solid-state components during long transmissions, the units feature an embedded internal thermostatic switch. If the internal enclosure or heatsink temperature exceeds +65°C, the unit automatically bypasses the power amplifier to protect the RF transistors from irreversible damage to the active junctions and emitter finger resistors.
Specifications
Both models share an identical high-power transmit architecture configured to run off a standard +13.8 VDC power source:
– Frequency Range: 50–54 MHz (factory optimized at 50.2 MHz and tuned for a 2 MHz bandwidth).
– Nominal Input Drive Power: 25 Watts.
– Nominal Output Power: 375 Watts.
– Class of Operation: Class AB Linear for the Power Amplifier stage (making it fully compatible with SSB, FM, and CW modes).
– T/R Switching Sensitivity: 0.5 Watts typical (RF sensing auto-switching).
– Maximum Antenna VSWR: 3:1 (VSWRs exceeding 3:1 risk transistor damage due to device power dissipation imbalances).
Power requirements: 13.8 VDC (nominal), 55 amps max.
0552G Preamp Specifications:
– Circuit Class: Class A Linear.
– Receive Preamp Gain: 15 dB nominal.
– Receive Preamp Noise Figure (NF): 0.6 dB nominal (utilizing a GaAs FET device rated at 0.5 dB NF with a +18 dBm 3rd-order intercept point for robust strong-signal intermod rejection).
