Also known as: RSP1A, SDRplay RSP1A
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SDRplay RSP1A is a low-cost, receive-only software-defined radio that tunes continuously from 1 kHz to 2 GHz with a 14-bit ADC and up to about 10 MHz of visible bandwidth.1 Built around the Mirics MSi001 tuner and MSi2500 sampling chip, it offers markedly more dynamic range and preselection than an RTL-SDR while staying in a similar price class.2
Key takeaways 14-bit, continuous 1 kHz–2 GHz, receive-only. The RSP1A gives you far more dynamic range and real front-end preselection than an 8-bit RTL-SDR, with a ~10 MHz span that can capture a trunked system’s control and voice channels at once. GopherTrunk support is network only: it drives the RSP1A over a SoapySDR/rtl_tcp bridge, not as a direct USB device — SDRplay’s closed API/service rules out the pure-Go USB path used for RTL-SDR, HackRF, and Airspy. Around $120. Like every receiver, it can’t decode AES encryption.
GopherTrunk support: network only. GopherTrunk drives the RSP1A over the network via SoapySDRServer/SoapyRemote (or an
rtl_tcp-style bridge), not as a direct USB device — you run SDRplay’s API service and a SoapySDR server on the machine it’s plugged into and mount it over TCP. GopherTrunk’s pure-Go USB drivers cover only RTL-SDR, HackRF, and Airspy. See the hardware guide and rtl_tcp notes.
Overview
The RSP1A is SDRplay’s entry-level model and the reference design the rest of the RSP line builds on. Its appeal for scanning and general monitoring is the combination of an uninterrupted tuning range — no LF/HF/VHF gap — with real front-end filtering: a bank of switchable preselection filters, an MW/broadcast-FM notch, and a software-controlled bias tee for powering an active antenna or LNA. Sampling at 14 bits gives it far better dynamic range and resistance to intermodulation than the 8-bit RTL-SDR, so strong nearby signals are less likely to desensitise the receiver or spray spurs across the band.
What it is
Internally the RSP1A is a Mirics chipset: the MSi001 is a broadband
zero-IF tuner, and the MSi2500 handles the ADC and USB interface.
The device streams raw IQ samples over USB 2.0; all channelisation,
demodulation, and decoding happen on the host. The maximum
displayed spectrum span is around 10 MHz, though the ADC actually samples faster and
decimates internally. Unlike the RTL-SDR, the RSP family is not libusb-generic —
SDRplay ships a closed API/service (the RSP driver daemon) that applications talk to,
and a SoapySDR module (SoapySDRPlay) that exposes the RSP through
the common Soapy interface used by GNU Radio,
SDRangel, CubicSDR, and others.
Variants
The RSP1A sits at the base of a family that trades up in front-end sophistication:
- RSP1 / RSP1B — the original RSP1 was simpler (fewer filters, no bias tee); the RSP1B refreshes the RSP1A with improved LF/MW performance and remains single-tuner.
- RSPdx — adds more preselection filters, three antenna ports, and a high-dynamic-range (HDR) mode optimised for LF/MW/HF.
- RSPduo — a dual-tuner design that can run two 2 MHz streams at once for diversity or simultaneous monitoring of separated bands.
All share the same underlying Mirics silicon and the same SDRplay API, so software support carries across the range.
Relevance to SDR
The RSP1A is a popular choice for HF through UHF listening: shortwave and amateur bands, ADS-B at 1090 MHz, VHF/UHF land-mobile, and broadcast monitoring. Its 14-bit converter and preselector make it a step up for crowded RF environments where an RTL-SDR would overload.
For trunking specifically, the ~10 MHz span lets it cover a system’s control and voice channels from a single capture, much like an Airspy. The practical caveat is the driver model: GopherTrunk drives RTL-SDR, HackRF, and Airspy hardware directly, whereas the RSP line depends on SDRplay’s proprietary API/service. Using an RSP1A with GopherTrunk therefore hinges on a SoapySDR/RSP bridge rather than a native backend — check the project status before assuming turn-key support. As a receiver the hardware is well suited to the task; the integration path, not the RF, is the limiting factor.
Where to buy
The RSP1A is sold by SDRplay and its distributors, and listed on Amazon. Before you buy it for GopherTrunk, remember the integration path: it is supported over the network only, through a SoapySDR/rtl_tcp bridge rather than GopherTrunk’s direct USB drivers — see the hardware guide. If you want a plug-and-play device, a RTL-SDR or Airspy is the simpler pick.
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 SDRs including the SDRplay RSP line. ↩
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RSP1A — SDRplay, official product page with tuning range, ADC resolution, filtering, and bias-tee specifications. ↩
Frequently asked questions
Does GopherTrunk support the SDRplay RSP1A?
Yes, but network only. GopherTrunk’s pure-Go USB drivers cover RTL-SDR, HackRF, and Airspy — not the RSP’s closed API/service. You drive the RSP1A over the network via a SoapySDRServer/SoapyRemote (or rtl_tcp) bridge: run SDRplay’s service and the Soapy server on the machine the RSP1A is plugged into, then mount it over TCP. See the hardware guide.
Is the RSP1A a good SDR for scanning trunked systems?
As RF hardware, yes — its 14-bit ADC, continuous 1 kHz–2 GHz coverage, and front-end preselection give it far more dynamic range than an 8-bit RTL-SDR, and its ~10 MHz span can cover a system’s control and voice channels in one capture. The only caveat is the integration path: it runs over a network bridge, not as a plug-and-play USB device.
Why can't GopherTrunk open the RSP1A directly over USB?
The RSP line is not libusb-generic. SDRplay ships a closed API/service that applications must talk to, so there is no pure-Go USB path the way there is for RTL-SDR, HackRF, and Airspy. The supported route is the vendor service plus a SoapySDR module, mounted over the network.
RSP1A or an RTL-SDR / Airspy for GopherTrunk?
If you want the simplest setup, a directly-supported RTL-SDR or Airspy plugs in and works with no bridge. Choose the RSP1A when you specifically want its 14-bit dynamic range and continuous HF-through-UHF coverage and don’t mind running a SoapySDR server for it.