cofdm repeater replay retransmitter with 1x TX 2 RX diversity for Extended Range and Obstacle Bypass

cofdm repeater replay retransmitter with 1x TX 2 RX diversity for Extended Range and Obstacle Bypass

Customized COFDM Repeater System (1TX / 2RX Diversity)

This custom-built COFDM repeater is specifically engineered to match the customer’s existing transmitter and receiver configuration, ensuring seamless signal relay, extended coverage, and reliable non-line-of-sight (NLOS) communication.

System Architecture

Input Signal Reception (1st link Side)

• Compatible with customer’s transmitter operating at 915 MHz (902–928 MHz ISM band)

• Equipped with dual 915 MHz receiving antennas

• Supports 2× RX diversity reception for improved signal stability and anti-multipath performance

Frequency Conversion Module

• Integrated RF BDC (Block Downconverter)

• Converts incoming signal from 915 MHz to 700 MHz band

• Enhances frequency flexibility and reduces interference

Re-Transmission (2nd link Side)

• Re-transmits signal using a 550 MHz antenna system

• Ground receiver uses dual 550 MHz receiving antennas

• Maintains diversity reception on the receiving end for maximum link reliability

Key Features

• ✔ Fully customized to match customer’s TX/RX frequency plan

• ✔ 1× TX / 2× RX diversity repeater architecture

• ✔ Built-in RF Block Downconverter (915 MHz → 700 MHz)

• ✔ Optimized for long-distance transmission

• ✔ Strong NLOS (Non-Line-of-Sight) performance

• ✔ Supports obstacle penetration and extended coverage

• ✔ Configurable RF output power: 2W / 5W / 10W (customizable)

Typical Applications

• Tactical communication systems

• UAV/drone signal relay

• Long-range video transmission

• Urban obstacle bypass deployment

• Temporary communication extension stations

Dimensions: Less than 200 × 150 × 40 mm (excluding protruding connectors)
Weight: Approximately 900 g – 1 kg

Bandpass RF filter

RF Filtering Considerations

Since the system operates with two independent wireless links, even though the operating frequencies are separated, additional RF filtering is recommended to ensure optimal performance.

To minimize potential interference, unwanted out-of-band signals, or second-harmonic emissions, it is advisable to install an external band-pass filter (BPF) between the antenna and the receiver RF connector.

Band-Pass Filter Design & Installation

• The band-pass filter is typically implemented as a separate external unit, rather than being integrated inside the repeater.

• This modular design allows:

  • Easy replacement or frequency customization

  • Flexible deployment based on field conditions

  • Convenient maintenance and upgrades

If the RF environment is clean and signal quality is stable, the filter can remain as a backup component and does not need to be connected.

Technical Characteristics

• Passive device (no power supply required)

• No signal directionality (bidirectional installation supported)

• Simple inline installation between antenna and RF input

• Improves system immunity against interference and harmonics