RTL-SDR Blog V4
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| Frequency | 500 kHz - 1.766 GHz (HF via built-in upconverter, VHF, UHF) |
| Bands | HF (via upconverter), VHF, UHF |
| Power | RECEIVE ONLY — no transmit. |
| Modes | All modes via SDR software |
| Weight | 25 g (0.9 oz) - ~25g. USB dongle with aluminum shielded case. |
| Connector | SMA-F |
| Year | 2023 |
| antenna | SMA-F |
| usb | USB 2.0 (power + data) |
| power req | USB bus powered. No external power required. |
Strong value: pocket money for 500 kHz-1.7 GHz. A built-in HF upconverter (just tune, no setup), a triplexer that isolates HF/VHF/UHF, notch filters, a 1 PPM TCXO, a bias tee, and an aluminum case. A dipole antenna is included. It has a large community and tutorial base, works with every major SDR software, and runs on a Raspberry Pi and Android.
Limited edition (the R828D is out of production; buy now or get the V3). An 8-bit ADC (the Airspy's 12-bit has better dynamic range). 2.4 MHz stable bandwidth (the Airspy Mini does 6 MHz). Receive only. No HF filtering (urban strong signals can still overload). The included dipole is adequate for testing only. The V3 remains available as a fallback.
A standout entry-level SDR. The RTL-SDR Blog V4 puts 500 kHz to 1.7 GHz into a pocket-money USB dongle with a built-in HF upconverter, triplexer, TCXO, and bias tee. It is a common first SDR. The R828D chip is out of production, making the V4 a limited edition; grab one while they last, or get the V3, which continues in production.
The RTL-SDR Blog V4 is the definitive budget software-defined radio: a tiny USB dongle that, paired with free software on a computer, turns into a wideband receiver covering roughly 500 kHz up to 1.766 GHz. It is built around the Realtek RTL2832U chip — which is the demodulator, not the tuner — paired with an R828D tuner. Crucially, it is receive-only; like all RTL-SDR dongles it cannot transmit.
What separates the V4 from earlier RTL-SDR dongles and cheaper clones is its HF handling. Rather than the awkward direct-sampling mode of the V3, the V4 has a proper built-in upconverter so the shortwave bands come in cleanly with full gain control. It also adds a triplexer to separate the HF, VHF, and UHF inputs, switchable notch filters to knock down strong broadcast stations, a 1 ppm temperature-compensated oscillator, and a software-switchable bias tee for powering a remote preamp. The catch is the 8-bit sampling shared by all RTL dongles, which limits dynamic range compared with premium receivers.
An important note for 2026: the V4 reached end-of-line when its R828D tuner chip went out of production, so new stock is drying up and a 'V4 Lite' successor is in the works. While they last, it remains the entry point to the hobby — a step up from the cheaper NooElec NESDR SMArt, and a world away in price from premium receivers like the Airspy HF+ Discovery.