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Receivers
Select 1.024 or 2.4 MS/s before connecting or switch between them during compatible RTL-SDR reception. Use 2.4 MS/s when complete DAB-ensemble bandwidth or improved microsecond-pulse sampling is more important than recording duration. The selected rate is read back from the tuner and stored in every recording.
HackRF Pro also offers 4.8, 9.6 and experimental 19.2 MS/s: the spectrum and native CI8 recordings cover the corresponding theoretical MHz span, while a bounded worker shifts and filters the selected channel to 2.4 MS/s for the existing decoders. Select the rate before connecting. Live 9.6 and 19.2 MS/s use the bundled WebAssembly channel filter; 4.8 MS/s remains available without it. Native recordings remain byte-exact and replay uses the same channel filter; the 2 GiB OPFS cap holds about 224 seconds at 4.8 MS/s, 112 seconds at 9.6 MS/s, or 56 seconds at 19.2 MS/s. The 32 MiB memory fallback is much shorter. Stable firmware v2026.01.1–v2026.01.3 is supported without upgrading firmware; stable rate/settings metadata records nominal USB-acknowledged values rather than claiming physical measurement.
bladeRF 2.0 Micro xA4, xA5 and xA9 share a receive-only profile for USB ID 2cf0:5250. BrowserSDR identifies the variant from the firmware-cached, CRC-checked calibration field before FPGA/RF configuration; the USB chooser identity, serial and product text do not distinguish models. xA4 retains the existing profile, while xA5 and xA9 remain experimental pending owner-run physical acceptance. All three select one physical input (RX1 or RX2) at a time, use native little-endian SC16 Q11 samples, offer slow/fast/hybrid AGC or manual gain with readback, and support 2.4, 4.8, 9.6 or experimental 19.2 MS/s. Wideband SC16 stays native across the acquisition thread and is processed in bounded spectrum/channel workers; the selected channel is filtered to 2.4 MS/s. BrowserSDR does not redistribute Nuand FPGA images. Download the exact official hosted image for the detected model from Nuand and import its .rbf; BrowserSDR accepts only the six catalogued model/version files after exact-size and SHA-256 verification, then stores a private copy in origin-local IndexedDB keyed by digest. Firmware 2.4 selects v0.15.3; firmware 2.5 or later selects v0.16.0 for volatile RAM loading. The image is verified again immediately before programming. An empty FPGA without the matching imported image fails before programming, and an incompatible preconfigured FPGA is left untouched. FPGA configuration disappears on power loss, while a verified browser copy can be reused. BrowserSDR never writes device flash, changes FX3 firmware or enables TX. Choose the input and gain under Device details & settings → bladeRF receive controls, then Apply bladeRF RX settings; reception briefly restarts on the same connection. Manual gain limits follow the tuned frequency and are not calibrated RF power. Native bladeRF recording/export preserves unchanged SC16 Q11 in SigMF pairs.
USRP support is deliberately limited to the Ettus B205-mini/B205mini-i at USB ID 2500:0022, using the receive-only profile pinned to UHD 4.9.0.0 commit 006d7f7646fb66f2ae635cb44ef6442a6ad4fba7, FX3 firmware 8.x and FPGA compatibility 7.x. It requires USB 3; BrowserSDR rejects USB 2 rather than offering an unverified reduced-rate mode. The profile has one RX channel, RX2, internal clock and time, selectable 4.8, 9.6 or experimental 19.2 MS/s native reception with matching analog-bandwidth request, a bounded 2.4 MS/s selected-channel path for existing decoders, slow-attack AGC with no calibrated gain value, and a 70 MHz–6 GHz center-frequency range (the requested channel must also fit the passband). Choose the rate before connecting and disconnect to change it. Requested frequency/rate and acknowledged or calculated accepted values are labeled separately; only AD9361 bandwidth is presented as a readback. At 19.2 MS/s a dedicated worker owns WebUSB, retains a bounded 768-read endpoint window, transfers validated native VRT/SC16 packet batches without normalizing on the acquisition worker, and leaves conversion to the existing spectrum/channel workers. This tier sustained a 90-second physical Chrome/USB 3 acceptance run with zero input skips or VRT discontinuities, but remains experimental pending loaded-host and browser/OS matrix soaks.
The official FX3 firmware and FPGA binary are not redistributed. Import the immutable b2xx_common_fw_default-g7f7d016.zip firmware archive (or its exact usrp_b200_fw.hex member) and the immutable b2xx_b205mini_fpga_default-gc37b318.zip FPGA archive (or its exact usrp_b205mini_fpga.bin member). BrowserSDR checks their pinned sizes and SHA-256 digests before connection and checks them again before a device write. If the device appears as WestBridge, BrowserSDR writes the verified Intel HEX records to FX3 RAM using the Cypress bootloader request, waits for the authorized runtime identity to re-enumerate, and then continues with the verified FPGA load. Both loads are volatile and disappear on power loss; BrowserSDR never writes EEPROM/flash, enables TX, or sends samples to the TX endpoint. Native CHDR/VRT SC16 recording preserves losslessly reordered CI16 I/Q for SigMF export and replay; it does not use CU8/CI8/Q11 scaling.
Use a current desktop Chromium browser over HTTPS or localhost. Close UHD and all other SDR software so the browser has exclusive ownership. On Linux, grant the logged-in user access to 2500:0022 with an appropriate udev rule and ensure no kernel or host process has claimed it; on Windows, the device interface must be bound to a WebUSB-compatible WinUSB driver. Import both artifacts before pressing Connect; running uhd_find_devices first is no longer part of the workflow. If permission is cancelled, retry Connect. If loading or re-enumeration is interrupted, disconnect/reconnect or power-cycle the radio, re-import if browser storage was cleared, and retry; no persistent device state needs repair. Authorized reconnect checks the exact VID/PID, descriptors, firmware, image/FPGA compatibility and USB speed again and never starts RF reception automatically. Physical acceptance depends on the device, rate, host and browser; see Known limitations.