QRO.cz RX Preamp and Bias Tee Module Box Combo

This powerful combo from QRO.cz includes the RX Preamp Module Box with a 2N5109 transistor and a Bias Tee Voltage Injector, offering a complete solution for enhancing receive-only antenna systems. The preamp is based on the proven W7IUV design and delivers up to 18dB of gain with a built-in variable attenuator, allowing precise control over signal amplification. A multi-turn potentiometer enables fine-tuning of the transistor bias for optimal linearity and performance. Two onboard relays automatically switch the unit to bypass mode when power is not present.

Power can be supplied either directly via an external DC source or through the included bias tee, which injects DC voltage into the coaxial feedline while isolating the radio from DC current. The bias tee simplifies installation by combining RF and DC over a single coaxial cable, making it ideal for powering remote devices like preamps, relays, or antenna switches. Together, these components provide a clean, efficient, and flexible receive system for antennas such as beverages, Double Half Delta Loops, flags, and other popular RX designs.

RX Preamp Box Key Features

• High Dynamic Range: Delivers up to 18dB gain with a real IP3 of 37 dBm, ensuring excellent linearity and signal clarity.

• Flexible Power Options: Operates from 12–15VDC via direct external DC connection or bias tee, with automatic bypass relays when unpowered.

• User-Adjustable Gain & Bias: Multi-turn potentiometers allow precise control of gain and transistor bias for optimal performance.

Bias Tee Box Key Features

• All-in-One Signal & Power Delivery: Combines RF signal and DC power over a single coaxial cable—ideal for powering remote preamps or active antennas without extra wiring.

• Advanced Protection Circuitry: Includes diode-based front-end protection, RF voltage/current limiters, and DC short protection to safeguard both your equipment and signal integrity.

• Customizable Performance: Features adjustable attenuation and high-pass filtering to fine-tune your installation, reduce AC noise, and manage high-gain preamps effectively.

RX Preamp Box Specifications

• Frequency Range: Broadband, 0.1 z to 30MHz

• Gain: Adjustable from 0 to 18 dB

• Impedance: 50-Ohm

• IP3 Rating: 37dBm at 18VDC / 90mA

• Output Power: Up to 26dBm

• Power Supply: 12–15VDC (direct or via coax)

• Current Draw: Up to 180mA (including relays)

• Connectors: UHF female SO-239

• Protection: Front-end diode protection (jumper-selectable)

• Bypass: Dual-relay automatic bypass when unpowered

• Assembly: Fully assembled and tested SMD version

• Enclosure: IP56-rated

• Dimensions: 3.94 x 3.94 x 1.97in. (100 x 100 x 50mm)

• Weight: 0.75lbs. (0.34kg)

Bias Tee Box Specifications:

• Frequency Range: 0.1 – 60MHz

• High Pass Filter: 100kHz ( > 40dB @ 25kHz)

• Insertion Loss: < 1dB – for minimal ATT

• Supply Voltage: DC Up to 24VDC

• Supply Current: Up to 500mA

• DC Short Protection: ~1A

• RF Voltage Protection: Up to 90V

• RF Current Protection: Up to 200mA

• Output Protection: RF diode limiter

• Front-End Protection: Diode-based

• Power Supply Common-Mode Filter: Integrated

• Variable Attenuator: Adjustable for gain control

• LED Diode Indicator: DC power status on coax

• Connectors: High-quality RF connectors