The RTL-SDR Version 4 was introduced late 2023. It is one of the most popular Software-defined Radio dongles.
In this post we compare the RTL-SDR V4 to RTL-SDR V3.
What are the improvements and should you upgrade?
Frequency Range and Receiver Architecture
The frequency range of both V3 and V4 are 500 kHz to 1.7 GHz.
The V3 processed low frequency signals in the range DC to 28.8 MHz using direct sampling mode. There are no filters and therefore any input signals are aliased. This can cause spurious signals to appear as artifacts in the FFT response. Put simply these signals don’t actually exist.
The V4 uses a built in upconverter instead of using a direct sampling circuit. In other words signals in the range 0 to 28.8 MHz are upconverted and processed by the receiver in the same way that signals up to 1.7 GHz are.
Other Improvements
- Notch filters in V4 reject strong AM and FM signals. The new R828D tuner chip has three inputs. The SMA input is split into three bands, HF (0-30 MHz), VHF (30 MHz to 300 MHz) and UHF (300 MHz+). This provides isolation between the three bands
- V4 has improvements in both Phase Noise and thermal heat dissipation,
- Bias Tee LED in V4 indicates when the BT is powering an amplifier.
Comparison Table
Here is a table that summarizes the key differences between RTL-SDR V4 and the earlier V3. We recommend the upgrade if you’re monitoring HF bands and want a cleaner spectrum over all.
| Specification | V3 | V4 |
|---|---|---|
| Architecture | Direct Sampling in HF band | HF Upconversion |
| Chipset | R860 | R828D |
| AM/FM Notch Filters | No | Yes |
| Phase Noise | Improved | |
| Bias Tee Indicator LED | No | Yes |
| Heat dissipation | Lower |
Related Posts
- Best Software-defined Radio
- RTL-SDR vs NESDR – which one should I buy?
- HackRF vs RTL-SDR
- Airspy vs RTL-SDR
- Best Portable Software-Defined Radios
