Also known as: RSPduo, SDRplay RSPduo
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SDRplay RSPduo is a dual-tuner receive-only software-defined radio covering 1 kHz to 2 GHz with 14-bit sampling on each tuner.1 Its distinguishing feature is two independent receiver chains that can operate at once — as two separate ~2 MHz streams on different frequencies, or as a coherent pair for antenna diversity.2
Overview
The RSPduo effectively packs two RSP-class receivers into one box, sharing a single USB connection and the SDRplay API. That opens uses no single-tuner SDR can manage: watch two widely separated bands simultaneously — say an HF net and a VHF control channel — or point two antennas at the same signal and combine them. It retains the family’s continuous 1 kHz–2 GHz tuning and 14-bit converters, but each tuner’s instantaneous bandwidth is capped around 2 MHz when both run together (a single tuner alone can go wider).
What it is
Each chain is a Mirics tuner and ADC; both stream raw IQ to the host over USB, where all demodulation and decoding happen. Two modes matter:
- Dual independent — the tuners sit on different centre frequencies, giving two unrelated ~2 MHz windows for parallel monitoring.
- Diversity / coherent — both tuners share a common clock and can be phase-referenced, enabling antenna diversity to fight multipath and fading, or experiments in coherent processing and direction finding.
The shared reference clock is what makes the coherent mode meaningful: without a common timebase, two receivers cannot be combined sample-for-sample.
Variants
The RSPduo is the only dual-tuner model in the RSP line; the single-tuner alternatives trade its second receiver for other strengths:
- RSP1A — the low-cost single-tuner baseline.
- RSPdx — a single tuner with the richest front-end filtering and an HDR mode for LF/MW/HF.
All three use SDRplay’s proprietary API/service and the shared SoapySDR module.
Relevance to SDR
The RSPduo’s niche is anything that benefits from two simultaneous, frequency-agile receivers: diversity reception, spectrum comparison across bands, and multilateration or direction-finding experiments that need phase-coherent captures. For trunking, the dual tuners could in principle follow a control channel on one receiver while a voice channel is tracked on the other, though the ~2 MHz per-tuner limit is narrower than an Airspy’s single wide capture.
As with every RSP, GopherTrunk has no native RSPduo driver — the hardware needs SDRplay’s closed API/service, reachable only through a SoapySDR bridge rather than GopherTrunk’s direct USB backends for RTL-SDR, HackRF, and Airspy. The receiver is capable; integration is the open question, so confirm current support before designing around it.
Where to buy
The RSPduo is sold by SDRplay and its distributors, and listed on Amazon — stock is often third-party, so the button is a tagged search that resolves to current listings. Before you buy it for GopherTrunk, weigh two things: it is supported over the network only, through a SoapySDR/rtl_tcp bridge rather than GopherTrunk’s direct USB drivers (see the hardware guide); and its second tuner only earns its price if you actually need two simultaneous receivers or antenna diversity. If you want a single 14-bit receiver, the RSP1B or RSP1A is cheaper; for plug-and-play trunking, an RTL-SDR or Airspy is simpler still. Compare radios in best SDR for GopherTrunk.
As an Amazon Associate, GopherTrunk earns from qualifying purchases — at no extra cost to you. It never changes what we recommend.
Sources
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Software-defined radio — Wikipedia, background on receiver-class and diversity-capable SDRs. ↩
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RSPduo — SDRplay, official product page describing the dual 14-bit tuners, shared clock, and diversity operation. ↩
Frequently asked questions
Does GopherTrunk support the SDRplay RSPduo?
Yes, but network only — like the rest of the RSP line. GopherTrunk’s pure-Go USB drivers cover RTL-SDR, HackRF, and Airspy, not SDRplay’s closed API/service. You run SDRplay’s service and a SoapySDR server (or an rtl_tcp bridge) on the machine the RSPduo is plugged into and mount it over TCP. See the hardware guide.
What can the RSPduo's two tuners do for scanning?
Two independent ~2 MHz receivers at once: one could sit on a control channel while the other tracks a separated band, or the pair can run coherently for antenna diversity against multipath and fading. The catch is the ~2 MHz per-tuner cap in dual mode — narrower than an Airspy’s single wide capture — plus the SoapySDR bridge requirement.
RSPduo, RSP1B, or an Airspy for GopherTrunk?
For plug-and-play trunking, a directly-supported RTL-SDR or Airspy is simpler. Choose an RSP1B if you want a single 14-bit receiver over a bridge; choose the RSPduo only if you specifically need two simultaneous tuners or diversity and don’t mind running a SoapySDR server.
Does the RSPduo decode encrypted channels?
No. Two tuners don’t change the encryption wall — like every SDR, the RSPduo cannot decode AES-encrypted traffic. It only receives clear signals for the host to demodulate.