Compare specifications of SDRplay RSP1, RSP2, RSPDuo, HackRF, PlutoSDR, and USRP B210 USB Software-Defined Radios.
Compare RSP1 RSP2 RSPDuo HackRF PlutoSDR USRP.
Here’s a practical, spec-level compare of the popular SDRs you named, with notes for radio astronomy / interferometry use.
| Device | RX freq. range | TX? | ADC bits / max usable BW | Duplex / #ch | Ext. ref / clocking | Notable strengths / limits |
| SDRplay RSP1 (today: RSP1A) | 1 kHz–2 GHz | No | 14-bit; up to ~10 MHz visible BW (bit-depth reduces above ~6 MS/s) | RX-only / 1 | No external ref on RSP1A | Very wide coverage with strong preselection/band-notches; great value for wideband survey & continuum work. (RSP1A datasheet.) (SDRplay) |
| SDRplay RSP2 / RSP2pro (discontinued) | 1 kHz–2 GHz | No | 14-bit; up to ~10 MHz visible BW | RX-only / 1 | Reference clock in & out (24 MHz) for sync | Multi-antenna inputs; can be locked to a GPSDO or daisy-chained for phase-stable multi-unit experiments. (Datasheet + app note.) (SDRplay) |
| SDRplay RSPduo | 1 kHz–2 GHz | No | 14-bit; 10 MHz per tuner (single) or 2 MHz each (dual) | RX-only / 2 tuners | High-stability ref + external clocking | Dual-tuner “diversity” and antenna A/B comparisons; clocking suited to scientific apps; handy for simple 2-antenna correlation/noise-cancel demos. (Product page & datasheet.) (SDRplay) |
| HackRF One | 1 MHz–6 GHz | Yes | 8-bit; up to 20 MS/s | Half-duplex / 1 | Clock in/out (SMA) | Huge tuning range + TX for very low cost; but 8-bit dynamic range is limiting for weak-signal RA; half-duplex only. (Official docs.) (hackrf.readthedocs.io) |
| Analog Devices ADALM-PLUTO (PlutoSDR) | 325 MHz–3.8 GHz (edu-hack to ~70 MHz–6 GHz is common) | Yes | 12-bit; up to ~20 MHz channel BW (61.44 MS/s internal) | Full-duplex / 1×1 | Rev C/D: external ref via U.FL | Compact TX/RX platform; precise external-ref support on newer revs; single-channel limits coherent arrays. (ADI page + specs + ext-clock refs.) (Analog Devices) |
| USRP (Ettus) B-series (e.g., B200/B210) | ~70 MHz–6 GHz | Yes | 12-bit; up to 56 MHz RF BW (USB 3) | B200: 1×1; B210: 2×2 MIMO | 10 MHz ref/GPSDO capable | Workhorse research SDRs; proper multi-channel coherence + wider instantaneous BW; costlier but best for phased arrays & real-time correlation. (Spec sheet / KB.) (Ettus Research) |
Quick take (for astronomy-leaning work at/near 1420 MHz)
- Survey / continuum / budget single-dish: RSP1A is great value with preselectors and decent 14-bit dynamic range; record a few MHz of clean spectrum easily. (SDRplay)
- GPSDO-locked single-channel or simple multi-unit sync: RSP2/RSP2pro (if you have one) or RSPduo—both support external clocking; RSPduo adds dual tuners for diversity/noise-mitigation experiments. (SDRplay)
- Two simultaneous phase-related channels in one box: RSPduo (dual tuners, 2 MHz each concurrently) is convenient for antenna A/B, null steering, or basic interferometry demos. For wider coherent BW and mature MIMO, USRP B210 wins. (SDRplay)
- Need TX (beaconing, calibration sources, instrumentation), or true full-duplex: PlutoSDR (1×1 full-duplex) or USRP (more channels, bigger BW). Pluto Rev C/D accepts an external ref via U.FL for stability; USRPs support 10 MHz ref/GPSDO natively. (Analog Devices)
- Massive tuning range + low cost TX/RX experiments: HackRF One covers 1 MHz–6 GHz and has clock I/O, but 8-bit depth limits weak-signal dynamic range compared with 12/14-bit radios. (greatscottgadgets.com)
Nuances that matter for you
- Clocking & coherence
- RSP2/RSPduo: Accept external 24 MHz ref; easy GPSDO locking and daisy-chaining for shared clocks. (SDRplay)
- PlutoSDR: Rev C/D adds a dedicated external reference connector (commonly 40 MHz); widely used with GPSDOs—handy for frequency-stable TX/RX test gear. (ez.analog.com)
- USRP B-series: Standard 10 MHz ref / PPS & GPSDO options; best-supported path for multi-channel coherence. (kb.ettus.com)
- Instantaneous bandwidth vs. bit-depth
- If you want wide (>10 MHz) coherent BW for correlation/fringes, USRP is the practical route. RSPs offer up to 10 MHz visibility (less when dual on RSPduo) and trade bit-depth at higher sample rates. (SDRplay)
- Transmit needs
- Only HackRF, Pluto, and USRP transmit. For lab beacons/cal, Pluto’s 12-bit chain and full-duplex are cleaner than HackRF’s 8-bit; USRP is the pro option. (Analog Devices)