Exploring the ATS-Mini: A Pocket-Sized Receiver with Big Aspirations

A recent Reddit post sparked my curiosity about an ultra-compact, budget-friendly radio known as the ATS-Mini—also referred to by its technical title, the V3 AMNVOLT Mini SI4732 DSP Radio Receiver. It's quite a mouthful, but its description is certainly accurate.

I purchased the unit from AliExpress for just USD 23.71, and despite its modest price tag, it claims support for a wide range of frequencies:

• FM: 64–108 MHz with RDS

• LW: 153–500 kHz

• MW: 520–1710 kHz

• SW: 1730–30,000 kHz

FM reception was surprisingly good - with RDS PI and text

SI4732: A Familiar Core

The heart of the receiver is the SI4732 DSP chip, commonly found in many low-cost radios, including the Tecsun PL-990 and XHDATA D-808. These retail for around USD 300 and USD 100, respectively—making the ATS-Mini a notable bargain.

Despite its compact dimensions (80×34×19 mm, 58 grams including battery), the device is packed with functionality. It includes an ESP32 microcontroller with Bluetooth and Wi-Fi capabilities—features rarely seen in radios of this size and cost.

Community Impressions and Durability Concerns

The online reaction has been mixed. While some users report their units failing shortly after purchase, others praise the device’s capabilities when it works properly. As with many community-developed hardware projects, quality control varies, but the enthusiasm is unmistakable.

Real-World Testing at KONG HQ

As with all new receivers I get my hands on, I first measure sensitivity. Using one of my longwire antennas, I compared it to the SDRPlay RSPdx and found it performed admirably—receiving similar signals with only some differences in audio quality.

It also handled adjacent-channel interference fairly well. Encouraged, I brought out my signal generator to push the device further.

Small...Smaller...Mini!

Technical Performance

• Sensitivity: Surprisingly strong, measured at around −100 dBm (~2 µV) for most of the frequency range.

• Low-frequency sensitivity roll-off: Present, but expected in this price bracket.

• FM sensitivity: Not formally measured, but reception of weak Finnish FM stations was comparable to more expensive gear

• Strong signal handling is somewhat on the poor side: Saturation began at −47 dBm (S9+30) and became total at −27 dBm (S9+50); roughly 20 dB behind more robust receivers. I used a method where I set up a feed from a signal generator 200 kHz away from the tuned frequency for this test.

Alternative layout, emphasizing signal levels

Battery Performance

The ATS-Mini is powered by an 800 mAh Li-Ion battery, rated at 3.7V.

It appears that certain hardware revisions suffer from rapid battery discharge, including notably high drain even while the device is not in use. Under typical usage conditions, the battery ought to last between six to eight hours, depending on the configuration—although enabling Wi-Fi will undoubtedly reduce this runtime. I managed eight hours and thirty minutes from a full charge to complete depletion with Wi-Fi disabled.

After recharging, I powered down the device and left it for twelve hours before switching it back on. During that period, the battery voltage had dropped from 4.13V to 4.11V, which I believe falls within acceptable limits. Another 14 hours later voltage read 4.10V. Furthermore, when the unit first arrived—after spending a couple of weeks in transit—it still retained a respectable level of charge. That leads me to believe my particular unit isn’t defective. However, numerous users have reported experiencing issues to the contrary.

Features and Functional Highlights

Despite limitations in signal handling, audio quality and durability, the ATS-Mini offers:

• Multiple reception modes including SSB. Yet, Synchronous AM is missing.

• RDS support for FM

• SMA antenna input, 3.5mm audio output, and USB-C charging

• Wi-Fi connectivity with support for access point mode

• Flexible firmware with multiple UI themes

• EIBI database support (still hit-or-miss for me)

The radio has no bandstop or bandpass filtering, making it effectively “wide open” and susceptible to overload in strong-signal environments.

Open-Source Ecosystem

What sets this receiver apart is the thriving community behind it. Developers and enthusiasts—many from GitHub—are actively enhancing both hardware and firmware:

• Enclosure and stand designs via downloadable CAD files

• A variety of tuning knobs

• Documentation for mods and firmware updates

• A growing library of shared knowledge and experimentation

While the user interface and jargon can feel daunting at first, this is part of what makes the project special: it's not just a product, but a collaborative effort.

Open for hardware mods! Not by this guy though... I've seen videos of people doing modifications with a soldering iron. Amazing.

Final Thoughts

Though it lacks the versatility of an SDR with wideband sampling, the ATS-Mini excels at what it sets out to do. It’s a simple, effective, and surprisingly capable receiver, ideal for travel or experimentation—just remember to bring a proper antenna.

For a device that costs less than a dinner out, its value is driven not just by the hardware itself, but by the passionate community improving it every day. It is a part of the radio hobby I haven't paid much attention to. And while the ATS-Mini is not the solution for hard-core MW DX-ers like myself, it will surely have a market.