UUGear’s VU GPSDR is a low-cost GPS-disciplined SDR expansion board designed specifically for the Vivid Unit, a palm-sized Rockchip RK3399-based touchscreen SBC we covered back in 2024.
The VU GPSDR is built around the RTL2832U ADC and Rafael Micro R860 tuner, but what makes it different from SDRs like the PhaseLatch Mini and DeepRad SDR is the integration of a u-blox NEO-M8N GPS module. This module provides a GPS-disciplined 24 MHz clock reference to the Si5351 local oscillator, which ensures high frequency stability and timing accuracy that is typically only found in much more expensive SDR hardware.
VU GPSDR specifications:
- Supported Platform – UUGear Vivid Unit via Vivid Unit Extender Gen 1/2 (See details below)
- MCU – STM8S003F for board-level controls
- RF
- Tuner – Rafael Micro R860
- ADC – Realtek RTL2832U
- Frequency Range – 500 kHz to 1.766 GHz
- Bandwidth – Up to 3.2 MHz (2.4 MHz recommended for stability)
- HF Support – Integrated 108 MHz up-converter for reception below 30 MHz (Shortwave/Amateur bands)
- Antenna
- 1x SMA (SDR input); no Bias-Tee
- 1x SMA Output (Software-controlled clock source via Si5351)
- Clocking
- Local Oscillator – Si5351, disciplined by 24 MHz PPS from u-blox NEO-M8N GPS
- GPS-adjusted clock for long-term frequency accuracy; falls back to internal TCXO without GPS fix
- 1x onboard GPS antenna connected via IPEX 1st gen connector; with 5V Bias-Tee support
- I2C header for NEO-M8N
- Misc
- Dual rotary encoders (software-configurable for tuning, volume, zoom, etc.)
- 2x push buttons for controls
- GPS fix green LED
- SWD header for STM8 MCU
- Dimension – 210 × 110 × 10 mm
- Weight – 0.065 kg
To use the SDR board, the Vivid Unit Extender is needed. The Extender gets connected to the back of the Vivid Unit via GPIOs and three other connectors, then the VU GPSDR board gets connected via the Vivid Unit Extender’s mini PCIe connector.
The company also mentions that the VU GPSDR supports both the Vivid Unit Extender gen 1 and gen 2. The main difference between the two is that the Gen 2 features a CH224K fast-charging controller, a quieter 4-wire blower-type fan for better thermals, and it also added screw terminals for external power supply; other than that, it includes over/undervoltage protection, RTC, watchdog, and more.
The VU GPSDR works with GPSDR++, a fork of the open-source SDR++ (v1.2.0) project. Because the Vivid Unit’s RK3399 SoC needs to handle real-time waterfall displays and demodulation, the company recommends enabling GPU acceleration for the Mali-T860 GPU to prevent lag. Installation for the Vue (Vivid Unit Extender) package and the gpsdrpp binary is straightforward via apt on the Vivid Unit’s Debian-based OS.
The VU GPSDR expansion board is available for €65.00 (approx. $77.40 USD) on the UUGear E-Shop. However, it is not a standalone device; you will also need the Vivid Unit (€99.00) and the Vivid Unit Extender (€28.00). The total cost for a complete handheld system is roughly €192 (approx. $205 USD), excluding antennas.
Debashis Das is a technical content writer and embedded engineer with over five years of experience in the industry. With expertise in Embedded C, PCB Design, and SEO optimization, he effectively blends difficult technical topics with clear communication
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