PoE Remote SDR Receiver with WIZnet W6300

RTL-SDR is usually connected directly to a PC over USB. This project moves the SDR receiver closer to the antenna and sends the received data over Ethernet instead.

The hardware is built around the Waveshare RP2350-POE-ETH, which combines an RP2350 MCU with a WIZnet W6300 Ethernet controller.

With PoE, both network connectivity and power can be delivered through a single Ethernet cable.

System Architecture

Antenna
   ↓
RTL-SDR
   ↓ USB
RP2350
   ↓
W6300
   ↓ Ethernet / rtl_tcp
PC / GQRX

The RP2350 handles USB communication with the RTL-SDR, while the W6300 provides the TCP/IP connection to the PC.

The project was tested at 250 kS/s, streaming about 488 kB/s, with FM and 118.1 MHz AM Airband reception verified in GQRX.

Hardware

How rtl_tcp Is Used

rtl_tcp is a TCP-based interface that allows SDR software to control an RTL-SDR remotely.

The PC sends commands such as:

• Center frequency
• Sample rate
• Gain
• AGC settings

For example, when a user selects 118.1 MHz in GQRX, the frequency command is sent through the W6300 to the RP2350. The RP2350 then applies the setting to the RTL-SDR through USB.

In the opposite direction, the RTL-SDR continuously sends I/Q data to the RP2350, and the W6300 streams that data back to GQRX.

This allows the remote SDR to behave similarly to a locally connected RTL-SDR.

Role of the W6300

The W6300 is the main network interface in this project.

It handles both SDR control traffic and the continuous I/Q stream between the embedded device and the PC. The main rtl_tcp connection uses TCP port 1234.

The project also uses Ethernet for:

• OTA firmware update
• Network logging
• Scanner configuration
• Multi-node scanner communication

Using rtl_tcp also means that existing SDR software such as GQRX can connect directly without requiring a custom PC application.

What the PC Does

Most SDR signal processing remains on the PC.

GQRX handles:

• Spectrum display
• Waterfall display
• AM/FM demodulation
• Audio output
• Frequency and gain control

This keeps the embedded device focused on RF data acquisition and network transport.

Dual-Core Data Handling

The RP2350 separates USB and Ethernet processing between its two cores.

• Core 0: RTL-SDR USB communication and I/Q acquisition
• Core 1: W6300 Ethernet and rtl_tcp streaming

A shared ring buffer transfers I/Q data between the two cores.

This helps maintain continuous data flow between USB and Ethernet.

Why PoE?

PoE is useful when the SDR receiver needs to be installed close to the antenna.

Instead of running a long RF cable to the PC, the RTL-SDR can be placed near the antenna and connected back to the network with Ethernet.

This can simplify rooftop, outdoor, or remote RF monitoring installations.

Applications

This architecture can be used for:

• Remote Airband monitoring
• ACARS reception
• FM reception
• rtl_433 sensor monitoring
• Remote RF monitoring
• Distributed RF scanning

The current implementation is best suited to narrowband applications because the RP2350 USB Host interface is the main bandwidth limitation.

Performance

The documented test setup achieved:

• Sample rate: 250 kS/s
• I/Q stream: about 488 kB/s
• USB errors: 0 in the reported test
• Client: GQRX
• Verified reception: FM and 118.1 MHz AM Airband

The main system limitation is the RP2350 USB Host interface rather than the W6300 Ethernet connection.

Comparison with Similar WIZnet Maker Projects

Two related WIZnet Maker projects are ADSBee and ESP32 MMDVM Hotspot.

The main difference is that this project sends raw SDR I/Q data to the PC.

ADSBee processes ADS-B signals on the embedded device and sends decoded aircraft information, while the MMDVM project acts more like a digital-radio-to-IP gateway.

Because the RP2350/W6300 project keeps most signal processing on the PC, the same embedded node can be used for several different RF applications.

Conclusion

This project turns a conventional USB RTL-SDR into a PoE-powered network SDR receiver using RP2350 and the WIZnet W6300.

The PC controls the SDR through rtl_tcp, while the RP2350 receives I/Q data over USB and the W6300 streams it back over Ethernet.

The result is a compact remote RF receiver that combines USB Host, dual-core processing, W6300 Ethernet, PoE, and existing SDR software compatibility in one embedded platform.