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RTL-SDR Blog V3 vs V4: Which to Buy
For scanning with GopherTrunk, the V3 and V4 decode identically — the choice comes down to HF handling and stock. Buy the V4 for built-in HF and better filtering while it is still available; buy the V3 if you want a dongle you can re-order for years. Both are proper RTL-SDR units with a real TCXO, SMA connector, and switchable bias tee.
Key takeaways V4 wins on HF (built-in upconverter, no fold) and filtering (notch + better band filters). V3 wins on availability — the V4 is end-of-line because its R828D tuner is discontinued. For VHF/UHF trunk-tracking they are equal. The V4’s extra filters cost ~2–3 dB of insertion loss. Neither decodes AES encryption.
Comparison at a glance
| RTL-SDR Blog V3 | RTL-SDR Blog V4 | |
|---|---|---|
| Tuner | R860 (R820T2 family) | Rafael Micro R828D |
| HF reception | Direct sampling (Q-branch) | Built-in upconverter |
| HF fold / aliasing | Folds above ~14.4 MHz | None — clean across HF |
| Input filtering | Basic | Notch + improved band filters |
| Insertion loss | Lower | ~2–3 dB higher (the filters) |
| TCXO | 1 ppm | 1 ppm |
| Connector / bias tee | SMA / switchable | SMA / switchable |
| Availability | Ongoing | End-of-line |
| Approx price (with kit) | ~$45 | ~$40–50 |
HF: direct sampling vs a built-in upconverter
This is the biggest technical difference. The V3 reaches HF by direct sampling — feeding the antenna straight into the ADC and listening on its second Nyquist zone. It works, but signals above roughly 14.4 MHz fold back down, you have to switch to a special Q-branch mode, and strong broadcast stations can alias into your passband.
The V4 puts a small upconverter on the board. It shifts all of HF up into a range the tuner handles natively, so shortwave, ham HF, and utility signals appear cleanly in normal quadrature mode with no fold and no images. If HF matters to you, the V4 is the easier, better receiver — no external upconverter box required.
For police/fire/EMS this is a non-issue. Trunked public-safety systems live in VHF/UHF (roughly 136–870 MHz), which both dongles cover natively and identically. The HF advantage of the V4 only matters if you also want to listen below 30 MHz.
Filtering vs insertion loss
The V4 adds notch filtering (to reject broadcast FM and other strong local signals) and improved input band filtering. In a strong-signal environment — near FM transmitters or cellular sites — that cleaner front end can be the difference between a clean control-channel lock and intermod hash.
The trade-off is honest: those filters add roughly 2–3 dB of insertion loss. On a weak, rural signal a couple of dB matters, and a mast-mounted LNA more than makes it back. In most suburban and urban setups the filtering is worth far more than the loss. If your problem is a genuinely weak signal rather than overload, that is a front-end dynamic-range issue no filter fixes — see when you actually need an Airspy.
The end-of-line reality
The V4’s R828D tuner has been discontinued, and RTL-SDR Blog has said the V4 is the last production run of that design. Nothing about your V4 stops working — it is a great dongle for years to come — but it will not be restocked once current inventory sells through. The R860-based V3 (and the wider NESDR SMArt class of R820T2/R860 dongles) continue in production, so they are the safer bet if you are buying several for a multi-dongle pool or want to standardise on something you can re-order.
Which should you buy?
RTL-SDR Blog V4
around $40
Built-in HF, best filtering, the enthusiast reference. Buy now if you want the best single dongle and can find one — it is end-of-line.
V4 on Amazon →RTL-SDR Blog V3 + dipole kit
around $45
Proven R860 dongle plus a real antenna, and a design that stays in production. The safe pick if you want to re-order or buy in quantity.
V3 kit on Amazon →Bottom line
If HF interests you and you can find one, the V4 is the better all-round receiver — built-in upconverter, cleaner filtering, the reference dongle. If you want something you can buy again next year, or you only care about VHF/UHF scanning, the V3 is every bit as good on the bands that matter and stays in production. Either way you are getting a proper TCXO-equipped RTL-SDR that runs GopherTrunk for about $40–45, and neither decodes encryption. Still deciding across brands? See the best RTL-SDR roundup and the best SDR overall.
Frequently asked questions
Should I buy the RTL-SDR Blog V3 or V4?
For VHF/UHF scanning with GopherTrunk, either is excellent and they decode identically. Buy the V4 if you want built-in HF without an upconverter and slightly better front-end filtering, and you can find one in stock. Buy the V3 if you want a unit you can re-order for years, since the V4 is end-of-line.
Is the RTL-SDR Blog V4 discontinued?
Effectively yes. The V4’s Rafael Micro R828D tuner is discontinued, so RTL-SDR Blog has stated the V4 is the last of its line. It still works perfectly, but once current stock is gone it will not be restocked, whereas the R860-based V3 continues.
What is the real difference between V3 and V4 on HF?
The V3 receives HF by direct sampling on the ADC’s second Nyquist zone, which folds signals above roughly 14.4 MHz and needs a Q-branch mode. The V4 adds a built-in upconverter so all of HF appears cleanly in normal quadrature-sampling mode with no fold and no aliasing images to fight.
Does the V4 have better filtering than the V3?
Yes. The V4 adds notch filtering and improved input band filtering that reject strong out-of-band signals — broadcast FM and cellular — better than the V3. The trade-off is a couple of dB of insertion loss from those filters, which is rarely a problem in practice.
Can either one decode encrypted police?
No. Neither the V3, the V4, nor any radio can decode AES-encrypted talkgroups. GopherTrunk decodes clear P25/DMR/NXDN/TETRA only. Choose based on the systems still in the clear in your area.
Do I need the V4's HF coverage for scanning?
Only if you also want shortwave, ham HF, or utility monitoring. Trunked police, fire, and EMS systems live in VHF/UHF (roughly 136–870 MHz), which both dongles cover natively. If you never touch HF, the HF difference between V3 and V4 does not matter.