COFDM Relay Repeater
COFDM Relay Repeater module for drone UAV wireless video transmitter and receiver Vcan1870
Table of Contents
Introduction
The module is a relay module, not a completed item. Customers need to add a power amplifier, filters, and receiving and transmitting antennas for it to work effectively. These need to be customized according to the two working frequencies selected by the customer.
To prevent interference, the drone employs a single frequency (e.g. 400Mhz) for communication with the relay, and a different frequency (e.g. 700Mhz) for communication between the relay module with the receiver. The separation between the two should be as large as possible.
Feature
- Wireless Video COFDM Video Data demodulation and re-modulation
- Stable signal transfer in NLOS and high-speed moving (less than 600km/hour)
- Adjustable working frequency, bandwidth, transmission power, etc (Special Parameter Configure Tool or UART STM32 LoRA )
- Lowest latency 200-300 milliseconds
- Widely frequency range 200Mhz-3000Mhz
- Support AES256
- Bandwidth 1Mhz-8Mhz optional
- Video signal repeater for long-distance
Introduction
Specification:
IO
| RF input | Two SMA females (to receive the signal) |
| RF output | MMCX female (to send out the signal again) |
| control UART | 4PIN PH1.25mm Connector |
| Power in | 2PIN PH2.54mm phenix Connector |
| TF-card | For firmware update |
| Power led | red LED, constant light when the device is normally powered |
| Link led | green led, blinks on transmitting the received data |
Demodulation and Modulation
| Modulation Formats | COFDM(DVB-T) |
| Carriers | 2K |
| Bandwidth | Configurable from 1MHz to 8MHz, step by 1KHz |
| FEC | 1/2, 2/3, 3/4, 5/6, 7/8 |
| Guard interval | 1/32, 1/16, 1/8, 1/4 |
| Constellation | QPSK, 16QAM, 64QAM |
| Bitrates | 0.5Mbps to 31.67Mbps |
RF Received
| Frequency Bands | 160MHz~860MHz (need an extra down converter block for 860-2300Mhz) |
| Tuning Step size | 1KHz |
| Sensitivity | -97±1dBm(BW=8MHz, QPSK, CR=2/3, GI=1/16) for one channel and add 3dBm for two-channel |
RF Transmitted
| Frequency Bands | 200MHz~2300MHz(other bands can be supported with special manufacturing) |
| Tuning Step size | 1KHz |
| Power out | Configurable, maximum -5dBm(subject to frequency) |
Monitoring and control
This COFDM relay repeater module can complete setup with our Parameter Configure Tool or STM32+LoRA (or other devices) via control uart. With our parameter configure too, the following parameters can be set:
– RX Received frequency (F1) and bandwidth (B1)
– TX Transmitted frequency (F2), bandwidth (B2), FEC, guard interval, constellation, and transmission power
Temperature range
Full specification: 0° to +70°C Ambient
Storage: –40° to +80°C
Power requirements
Input range: 7~24VDC
Power consumption: <250mA@12V
Physical Characteristics
Dimensions: 73x51x15mm
Gross Weight: 32.4 grams
UART AT commands
The AT commands mainly used in the COFDM Wireless Relay Repeater are ATDR, ATSD, ATGD, ATSR, ATGR, and ATGB. For the introduction of specific commands, see the document.
FAQs
- Our COFDM Video Transceiver relay repeater supports 170-860Mhz. The COFDM transmitter also supports 2300Mhz, but the COFDM receiver only supports up to 860Mhz, 861-930Mhz receiver our COFDM-221 supports, over 930Mhz-2300Mhz needs to plus the frequency downconverter block to support.
- Our COFDM relay repeater module supports all the COFDM transmitters and receivers, the transmission distance depends on your external power amplifier and filter support.
At the moment, adding a monitor is not feasible.
The current COFDM repeater design does not include any display output interface, and it also does not support video decoding functionality. The repeater works by directly receiving the COFDM data stream from the receiver module, changing the RF frequency, and retransmitting the data exactly as received.
This architecture is intentionally designed to achieve:
- The simplest and most reliable implementation
- Ultra-low latency
- Minimal processing delay
Since the unit does not decode the video stream internally, there is no video signal available for a local monitor display.
Technically, yes — Ethernet output can be added.
However, this would require additional software and hardware development, including:
- Data buffering and forwarding logic
- Network transmission program development
- Web-based configuration interface
- IP address and port management functions
- System testing and optimization
Because of the extra development workload, this feature would typically require:
- A sufficient order quantity, or
- A separate NRE/development fee
If your project has volume demand or a dedicated budget for customization, we can evaluate this option further.
The COFDM repeater module itself does not include a built-in display or video output interface, so it cannot directly show tuning status or video images. This is because the repeater is designed as a transparent RF relay device that focuses on low latency and real-time frequency translation, without performing video decoding.
However, the system can still be monitored and optimized in the following ways:
1. LCD Parameter Configuration Tool Board (Recommended)
The repeater can be connected to an external LCD parameter configuration tool board.
Through this tool, you can directly monitor key RF performance indicators such as:
- Received signal strength (RSSI)
- Signal quality (SNR)
- Bit error rate (BER)
- Link status and other RF parameters
These indicators are commonly used to determine whether the link is properly tuned and operating under optimal conditions.
2. Using an External Receiver for Video Monitoring (Optional)
If real video monitoring is required, you can connect a standard COFDM receiver near the repeater output side.
In this case:
- The repeater still performs RF frequency translation only
- The receiver handles video decoding
- You can connect the receiver to a display or monitor to view the live video
This effectively allows you to check system performance visually if needed.
Important Note
The COFDM repeater itself:
- Does not support video decoding
- Does not output HDMI / CVBS / IP video signals
- Only performs transparent RF relay with frequency conversion
The below model is good for a two-way TDD bidirectional link of the Wireless relay transmitter and receiver or wireless transmitter and receiver relay repeater.
iVcan.com –
The Vcan1870 COFDM Relay Repeater module is an excellent addition to any UAV or drone wireless video transmission setup. Designed as a flexible relay, it reliably demodulates incoming COFDM signals and instantly re-modulates them for transmission, ensuring stable long-range video links. Its adjustable frequency, bandwidth, and transmission power make it highly adaptable for different environments, while support for AES256 ensures secure communication. With low latency of 200–300ms and robust NLOS performance even at high speeds, this module is perfect for professional drone applications requiring reliable, high-quality video relay.