REXON PA-10/AIR linear AM amplifier for air-band hand-held transceivers

PA-10/AIR is linear AM amplifier designed for air-band applications. It is primarily intended to enhance the range of hand-held transceivers by boosting transmitter power and increasing receiver gain if required. With PA10 Booster the power outputwill be  13W carrier and  50W pep (mainly for ground to the air communication).
In the world of aviation, equipment reliability is paramount and PA-10/AIR addresses this need in following ways:
– AM modulation indicator blinks as user talks, confirming that voice message is transmitted on air. This function immediately points out defective microphone issue.
– Supervising microprocessor recognizes the situation when amplifier can't deliver expected RF power and immediately switches to bypass mode, connecting transceiver directly to antenna. The situation of „transmitting” through „burned” amplifier does not happen.
– The problem of defective or improperly tuned antenna is detected and signaled. Amplifier stays in bypass mode to protect itself.
– Excessive input power, caused by transceiver malfunction or misapplication causes alarm and transition to bypass mode.
– The DC power supply voltage outside acceptable range causes alarm and amplifier returns to bypass mode.
– Excessive temperature of the amplifier causes alarm and return to bypass mode
All alarm indicators (LEDs) are red. Anything red is lit – there is a problem. This scheme relieves user from paying too much attention to the signaling.
PA-10/AIR features automatic gain control, implemented by digital step attenuator. It adapts amplifier gain to varying carrier power of transceiver, always leaving proper headroom for  AM modulation. No modulation clipping ever occurs.
For the receive path – low noise preamplifier is available. It also features input bandpass filter, eliminating danger of cross-modulation caused by nearby CB stations.

FRONT PANEL DESCRIPTION

SWITCHES

• TX BOOSTER Enables function of power amplifier
• RX PREAMP Enables function of receiver preamplifier Operation announciators
• POWER ON Green LED lit when unit is DC powered and switched on
• BOOSTER ON AIR Yellow LED lit when power amplifier is operating, delivering power to the antenna
• AM MODULATION Yellow LED lit when AM modulation above appr. 30% has been detected (user presses transceiver PTT and talks to the microphone) Alarm announciators
• HIGH SWR Red LED lit when antenna SWR beyond 2:1 has been detected. Amplifier stays in bypass mode, protecting power transistors.
• OVERDRIVE Red LED lit when excessive carrier power at the input has been detected. Amplifier stays in bypass mode.
• DC VOLT Red LED lit when DC supply voltage is too high or too low. Amplifier stays in bypass mode.
• HIGH TEMP. Red LED lit when excessive temperature near power transistor has been detected. Amplifier stays in bypass mode.
• PA FAIL Red LED lit when amplifier failure has been detected. Amplifier stays in bypass mode.

SPECIFICATIONS

• Frequency range: 118 MHz – 137 MHz
• Mode: Primarily AM, FM allowed
• RF output power (carrier): 12W-14W (Controlled by digital ALC)
• RF input power (carrier): Nominal: 1.5 W Maximum (appr.): 3 W Minimum: 1 W
• DC supply voltage: Nominal: 12.5 V Minimum: 10.5 V Maximum: 14.5 V
• DC supply current during transmission: Typical: 4A
• Receiver preamplifier gain: Typical: 21 dB
• Receiver preamplifier noise figure: Typical: 1.9 dB
• RF connector type: UHF (SO-239)