ATS Mini vs ATS20+ Technical Comparison
The ATS Mini and ATS20+ are two compact, budget-friendly shortwave radio receivers built around the Silicon Labs SI4732 chip, offering FM, AM, and SSB capabilities. Popular among radio enthusiasts, hobbyists, and SWL (shortwave listening) communities, these devices promise portability and functionality at an affordable price. This technical review compares the ATS Mini and ATS20+ in terms of sensitivity, SSB reception, AGC functions, build quality, and extra features to help you choose the right receiver for your needs.This critical technical review examines both receivers honestly, highlighting their significant limitations alongside their modest capabilities. Let’s dive into the details!
The Si4732 Reality Check
Both receivers are built around Silicon Labs’ Si4732 chip, which brings inherent limitations that no amount of clever implementation can fully overcome. The chip’s built-in noise and limited dynamic range affect both models equally, setting a performance ceiling that traditional analog receivers often exceed.
Overview of ATS Mini and ATS20+
Before comparing, here’s a brief overview of both devices:
- ATS Mini: A compact, hobbyist-oriented receiver with basic controls (often just an on-off switch and a knob). Available in V1 and V3 versions, with V3 featuring improved antenna impedance adjustments and a separate headphone amplifier. It’s designed for simplicity and experimentation.
- ATS20+: An upgraded version of the ATS-20, featuring a 0.96-inch OLED display, pre-configured commercial and ham radio bands, and advanced firmware options. It’s marketed as a full-band receiver with DSP (Digital Signal Processing) and SDR (Software-Defined Radio) capabilities.
Both radios target portable shortwave listening, but their performance varies. Below, we analyze key technical aspects to highlight their strengths and weaknesses.
1. Sensitivity
Sensitivity determines a radio’s ability to pick up weak signals, a critical factor for DXing (long-distance reception).
ATS Mini Sensitivity
The ATS Mini, particularly the V3 version, shows moderate sensitivity with external antennas like the MLA-30+ loop or a 20-foot wire. However, testing reveals it struggles to pick up weaker stations compared to higher-end receivers like the Tecsun PL-330.
The V3’s antenna impedance adjustment improves sensitivity slightly over the V1, but it’s still not a DX machine. Users report poor reception with the included telescopic antenna, requiring external setups for decent performance. Medium wave (MW) and shortwave (SW) reception are functional but lack the finesse needed for faint signals, especially without proper antenna configurations.
ATS20+ Sensitivity
The ATS20+ demonstrates good sensitivity across AM, FM, and SW bands, thanks to the SI4732 chip’s high sensitivity and selectivity. Users report successful reception of major broadcasters like China Radio International and Voice of Greece, as well as utility stations like HF VOLMET. It performs well with a 16-foot wire antenna, pulling in distant stations like KRMG Tulsa (90 miles away) on 740 kHz.
However, the ATS20+ can overload easily with strong signals, requiring AGC adjustments or shorter antennas to mitigate interference. FM reception is particularly strong, with fast RDS (Radio Data System) display.
Sensitivity Verdict
The ATS20+ edges out the ATS Mini in sensitivity, offering better performance for SW and MW reception, especially with external antennas. The ATS Mini’s V3 improvements help, but it falls short for weak signal detection, making the ATS20+ a better choice for serious DXers.
2. SSB Reception
Single Sideband (SSB) reception is crucial for amateur radio and utility stations, requiring precise tuning and clear audio.
ATS Mini SSB Reception
The ATS Mini’s SSB performance is lackluster. Users report difficulty tuning SSB signals due to limited BFO (Beat Frequency Oscillator) control and coarse tuning steps.
Audio quality in SSB modes (LSB/USB) is subpar, with noticeable distortion and insufficient volume, especially on V1 models. The V3’s headphone amplifier improves audio slightly but doesn’t address tuning issues. Compared to radios like the Tecsun PL-680, the ATS Mini struggles with SSB clarity, making it less suitable for ham radio enthusiasts.
ATS20+ SSB Reception
The ATS20+ offers decent SSB reception with independent LSB/USB modes and variable BFO control. Users praise its ability to monitor amateur radio, HF VOLMET, CW, and RTTY signals.
Firmware updates, such as those from Goshaante (GitHub), enhance SSB accuracy by allowing BFO calibration (e.g., correcting a 20 Hz offset). This ensures clearer audio when tuned to standard frequencies. However, SSB audio can suffer from overload and AGC clipping with strong signals, and the BFO offset is non-linear (450 Hz at low HF to 1.9 kHz at high HF).
SSB Reception Verdict ATS Mini vs ATS20+
The ATS20+ significantly outperforms the ATS Mini in SSB reception, offering better audio clarity, tunable BFO, and firmware upgrade potential. The ATS Mini is not a viable option for serious SSB listening.
3. AGC Functions
Automatic Gain Control (AGC) manages signal strength to prevent distortion from strong signals and boost weak ones.
ATS Mini AGC
The ATS Mini’s AGC is basic and inconsistent. Both V1 and V3 versions allow AGC on/off toggling, but the function is too aggressive, quickly returning to full gain between words on SSB, raising background noise.
Users report “bouncing” AGC when tuning, requiring a pause at each frequency step to let it settle, which disrupts the listening experience. No real AGC adjustments are available, limiting its ability to handle varying signal conditions effectively.
ATS20+ AGC
The ATS20+ provides more flexible AGC options, including on/off toggling and attenuation settings. However, its AGC is also criticized for being too quick, causing noise spikes between SSB syllables.
Firmware updates improve AGC performance slightly, but strong signals still cause clipping distortion. Users often disable AGC for SSB and use external attenuators (e.g., -20 dB) to manage overload. The ATS20+’s AGC works better for AM and continuous signals like Wefax, but it’s not optimized for dynamic SSB conditions.
AGC Verdict
Neither radio excels in AGC performance, but the ATS20+ offers more control and benefits from firmware tweaks, giving it a slight advantage over the ATS Mini’s rudimentary AGC.
4. Build Quality
Build quality affects durability, portability, and user experience.
ATS Mini Build Problems and Variant Confusion
The ATS Mini suffers from severe quality control issues exacerbated by multiple vendors producing different versions. Units from various Chinese manufacturers often ship without properly soldered BOOT and RESET buttons, indicating poor quality control across the supply chain. The plastic case feels flimsy, and the display is barely readable in bright conditions. Button response is inconsistent, and the rotary encoder feels cheap and prone to failure.
The market confusion is worse than the build quality. Multiple vendors sell units labeled as “ATS Mini” with different PCB layouts, component quality, and firmware versions. Some variants use inferior displays, cheaper rotary encoders, or different antenna connectors. This vendor proliferation makes it nearly impossible to know what you’re actually buying, with no standardization or quality assurance between sellers.
ATS20+ Construction Issues
While the ATS20+ features an aluminum alloy case, the overall build quality remains questionable. The case design traps heat, causing stability issues during extended use. The button layout is cramped, and the display backlight is inadequate. The telescoping antenna connection is loose on many units, affecting reception quality.
Build Quality Verdict
The ATS20+ clearly surpasses the ATS Mini in build quality, with a durable metal case, better display, and upgrade-friendly design. The ATS Mini feels like a budget hobbyist device with limited durability.
5. Power Management: Underwhelming Battery Life
ATS Mini Power and Battery Discharge Crisis
Current draw ranges from 80mA to 120mA depending on display brightness, but these figures are misleading when considering the latest firmware versions. Recent ATS Mini variants suffer from a critical battery discharge problem that renders the receiver nearly unusable. The latest firmware iterations have introduced power management bugs that cause excessive standby current draw, often exceeding 50mA even when the unit appears to be “off.”
This battery discharge issue has become endemic across multiple vendor variants. Users report fully charged batteries draining completely within 24-48 hours of non-use. The problem appears to stem from improper ESP32-S3 sleep mode implementation in recent firmware builds, combined with inadequate power management circuits in the newer PCB revisions. Some vendors have attempted firmware fixes, but these often introduce new instability issues or fail to address the root cause.
Real-world battery life during active use rarely exceeds 4-6 hours with newer units, significantly worse than the 6-8 hours achievable with earlier versions. The power management system lacks sophistication, with no effective sleep mode or power-saving features during idle periods. Many users have resorted to physically disconnecting the battery when not in use, defeating the purpose of a portable receiver.
ATS20+ Battery Reality
The 800mAh lithium battery sounds adequate but delivers disappointing runtime. Type-C charging is convenient, but the charging circuit is basic and slow. Battery life degrades noticeably after several months of use, and replacement requires disassembly that voids any warranty.
Reality Check: Battery performance is mediocre on both receivers, requiring frequent charging during field use.
6. Extra Features
Extra features add functionality and user convenience.
ATS Mini Features
- Limited Features: The ATS Mini is bare-bones, with basic FM, AM, and SSB modes. The V3 adds a headphone amplifier and antenna impedance tuning, but lacks advanced DSP or SDR capabilities.
- No Display Memory or RDS: Unlike competitors, it has no RDS for FM or memory presets, restricting its appeal for casual listening.
- Open-Source Potential: Its simple design appeals to Arduino hobbyists for custom firmware, but this requires technical expertise.
ATS20+ Features
- Rich Feature Set: Includes a 0.96-inch OLED display with support for auto-hold settings after power failure, and 22 pre-configured commercial and ham bands.
- DSP and SDR: DSP enhances signal selectivity, and open-source firmware (e.g., PU2CLR’s Arduino Library) supports RDS, audio bandwidth filters (0.5–4 kHz), and BFO control.
- Audio Outputs: Supports 3.5mm headphones and a 4 ohm speaker with 2W output, plus USB-C charging.
- Firmware Upgrades: Community-driven updates improve ergonomics, SSB calibration, and band coverage (e.g., custom HAM band plans).
Extra Features Verdict
The ATS20+ dominates with its extensive feature set, including DSP, RDS, and firmware upgradeability, making it far more versatile than the basic ATS Mini.
ATS Mini vs ATS20+ Price Reality: You Get What You Pay For
At around $33-41 for the ATS20+ and typically $20-30 for various ATS Mini variants, these receivers represent the absolute bottom tier of the market. The rock-bottom pricing reflects severely compromised performance, poor build quality, and limited longevity. Users expecting performance comparable to higher-end receivers will be disappointed, but the pricing explains why corners have been cut so drastically.
ATS Mini vs ATS20+ – Conclusion
Both the ATS Mini and ATS20+ represent the commoditization of shortwave receivers, prioritizing low cost over performance. Neither delivers the listening experience that serious radio enthusiasts expect. The Si4732 chip’s limitations ensure that both receivers perform similarly poorly across most metrics and makes ATS Mini vs ATS20+ war unconclusive.
The ATS Mini situation has become particularly problematic with recent versions suffering from critical battery discharge issues that make the receiver impractical for portable use. Combined with the confusion created by multiple vendors selling incompatible variants, the ATS Mini has evolved from a budget compromise into a frustrating experience that often leaves users with non-functional units.
For casual listeners with minimal expectations, the ATS20+ provides more consistent (albeit still limited) functionality. The ATS Mini’s vendor chaos, battery problems, and quality control issues make it difficult to recommend despite its lower price point. Users seeking any degree of reliability should avoid the ATS Mini entirely and consider the ATS20+ or save money for better alternatives.
These receivers succeed only in demonstrating that modern silicon radio technology, when implemented cheaply, cannot match the performance of well-designed analog circuits. They serve as functional but uninspiring tools rather than engaging radio equipment.