Why don't all ATS20s ship with this? Stability and legality. Exclusive firmware often pushes the microcontroller to 100% usage, causing occasional audio stutters or encoder lag. Furthermore, unlocking the full frequency range (e.g., cellular bands or aviation below 118MHz) is illegal in many jurisdictions. The community builds these "exclusive" features as proofs of concept, but they warn that using the 0-30MHz continuous TX (transmit—though the hardware can't really transmit cleanly) or out-of-band reception could violate local laws.
While the hardware (SI4735 chip) handles the signal, the firmware dictates how it is processed. Custom builds often tweak the Digital Signal Processing (DSP) parameters, resulting in:
Because these firmware files are community-created, there is no single "official" store. Always download from reputable developer pages on GitHub or trusted radio forums (like RadioReference or SWLing Post forums) to avoid malicious files.
The "exclusive" firmware for the ATS-20+ Si4732 (often referred to as ATS_EX) is considered a "game-changer" by enthusiasts on forums like The QRPer Board . Developed primarily by Goshante, this community-driven update transforms the budget receiver from a basic listener's toy into a surprisingly capable tool for ham operations and serious shortwave DXing. Key Features & Enhancements
The ATS_EX firmware is widely praised for fixing clunky stock interfaces and unlocking technical capabilities previously unavailable on the base model.
Reworked Interface: Replaces "ugly" stretched fonts with a minimalistic, highly readable layout, including a 7-segment frequency font and an optional relative S-meter.
Precision Tuning: Merges the BFO with the main frequency, allowing for seamless tuning as low as 10Hz steps in SSB mode, which eliminates the "Donald Duck" voice effect on amateur radio signals.
Expanded Band Coverage: Provides continuous coverage for LW (153–520 KHz), MW (520–1710 KHz), and a unified SW band (1710–30,000 KHz). ats20 firmware exclusive
Advanced Settings: Adds a settings page to configure Gain Control (ATT), Soft Mute, Automatic Volume Control (AVC), and SSB Sync mode.
Responsive Controls: Increases the CPU frequency of the Atm328p controller to its full clock speed, resulting in faster encoder response and more fluid menu navigation. Performance Verdict
Reviewers from RadioReference note that while the firmware drastically improves the user experience, it cannot overcome hardware limitations like poor front-end filtering.
ATS_EX firmware goshante on GitHub is the most widely discussed "exclusive" or advanced upgrade for the ATS-20+ radio. It is often described as a "game changer" that transforms the device from a basic shortwave toy into a viable tool for amateur radio operations. Key Features & Improvements Reduced "Chuffing":
Significant reduction of the "soft mute" effect, making scanning through bands much smoother. Fine-Tuning: Adds a precise 10 Hz tuning step
for SSB (Single Sideband), which is essential for clearly receiving ham radio operators. Visual Overhaul:
Introduces a cleaner, high-contrast display with larger fonts that are easier to read than the original factory version. Advanced Audio Tools: Includes a Synchronous Detector (SAM) Why don't all ATS20s ship with this
for AM modes to reduce fading distortion and the ability to adjust receive bandwidth via the encoder. Battery Management:
For the ATS-20+, it supports built-in battery level indication using existing resistor dividers. Performance & User Experience
Users frequently highlight that this firmware pushes the hardware to its absolute limits; the developer has stated that the flash memory is nearly full, so further feature requests are generally closed. While many praise the S-meter implementation
as the best available for this device, some users have noted minor audio distortion when the S-meter is active during SSB reception. Installation Notes
Title: Just flashed the actual ATS20 “exclusive” firmware – huge difference!
Body:
Forget the generic SI4732 builds you find everywhere. I finally got my hands on the ATS20 “exclusive” firmware (the one that’s supposedly optimized only for the ATS20 board, not generic SI4732 modules).
What changed:
Plus, the FM de-emphasis is finally correct for US/EU (selectable).
Heads-up: This is NOT the same as the “SI4732_ATS20” firmware from the public repos. The “exclusive” version has different pin mappings and AGC tuning.
Anyone else tried it? I can share the hex if mods allow.
#ATS20 #SI4732 #SDR #FirmwareExclusive
Exclusive firmware often appeals to preppers and field operators. One build introduced "Air Gap Mode." When activated:
This allows the user to monitor frequencies in complete darkness and silence, with the only indication being a silent haptic (if modified) or a headphone trickle. Stock firmware has no concept of tactical silence.