While there is no formal "white paper" in the academic sense for the ATS-20 firmware, several comprehensive technical guides and community-developed manuals (often distributed as PDFs or GitHub documentation) serve as the definitive "papers" for this hardware The ATS-20 and ATS-20+ radios typically run on Atmel ATmega328P (Arduino Nano/Uno) or
architectures, and the most prominent documentation revolves around advanced community firmware Core Technical Documents & Firmware Types ATS_EX Firmware (Goshante)
: This is widely considered the standard "advanced" firmware for the original ATS-20/20+. The ATS_EX Manual (PDF)
detail its reworked interface, 10 Hz SSB tuning steps, and improved BFO management ATS_MINI Firmware
: Geared toward the ESP32-based variants (often called the ATS Mini), this documentation covers features like Wi-Fi connectivity and EIBI station database integration PU2CLR Library
: The foundational code for most ATS-20 firmware is based on the PU2CLR Si4735/Si4732 Arduino Library
. Technical discussions and "papers" regarding the Si4732 chip's SSB patches are often found in this repository's wiki. Technical Specifications & Schematics
The hardware architecture is documented through community-traced schematics, as factory versions are rarely released: Schematics : Traced diagrams for the ATS-20+ (GitHub PDF)
outline the Arduino Nano integration and the potential divider used for battery monitoring Key Hardware Tweak : A common "paper" or guide topic involves the battery monitor fix ats20 firmware
. On the ATS-20+, users must often edit the firmware source code to change #define BATTERY_VOLTAGE_PIN to get accurate readings Firmware Comparison
ATS 20+ : ATS_EX Firmware... adding the battery level circuit.
Updating the firmware on an radio is the single best way to improve its usability, as the stock firmware (typically version 1.1.5) is often considered functional but basic. Popular Firmware Options ATS_EX (Goshante)
: Widely considered the best upgrade for the standard ATS20/ATS20+. It features a completely reworked, non-stretched UI and replaces the clunky BFO menu with seamless frequency surfing. H.J. Berndt Firmware
: A feature-rich alternative that adds advanced tools like an RTTY/CW decoder , signal plotter, and a waterfall display. PU2CLR (Ricardo Caratti)
: The foundational community firmware that many others are built upon. It provides reliable SSB support and expanded band coverage. Key Feature Improvements Lets upgrade the ATS 20+
The ATS20 (often the ATS-20+ or Plus model) is a popular, budget-friendly "all-band" radio receiver based on the SI4732 chip and Arduino hardware. Firmware updates are a frequent topic for users looking to unlock features like SSB (Single Side Band) support, improved scanning, or custom band presets. Recommended Firmware Options
PU2CLR (Ricardo Caratti): Often considered the gold standard for stability. Version V1.1.5 is a common factory-loaded or stable baseline for many units. While there is no formal "white paper" in
Goshante (goshante/ats20_ats_ex): A popular alternative that expands the radio's capabilities. Version 1.18 is frequently cited, though some users find the installation more complex due to screen scaling or hardware compatibility issues.
Pro Tip: A "simplified" guide for the Goshante 1.18 update is available on the G4ZAL Blog. Critical Hardware Warnings
Updating the ATS20 is notoriously tricky due to manufacturing variations:
Bad USB Ports: Many ATS-20+ models shipped with Arduino Nano clones that have faulty USB ports or incompatible CH340 drivers. If your computer doesn't recognize the radio, you may need to replace the Nano or use an external programmer.
External Programmers: If the standard USB cable fails, users often resort to using a USBasp or a second Arduino Uno/Nano acting as an ISP programmer.
Battery Voltage Bug: Some firmware updates cause the radio to stop displaying battery voltage correctly. A common hardware fix involves a "solder blob" between specific pins (ADC1/ADC2) on the Nano board. How to Update Uno ISP programmer for ATS20 firmware update? - Facebook
Your new firmware will likely work, but the frequency readout may be off by 1-2 kHz. Here is how to fix it:
The ATS-20 is a fascinating piece of hardware that punches above its weight class, largely thanks to the efforts of the open-source community. If you own an ATS-20X and feel limited by the factory settings, exploring community firmware is the best way to unlock the device's true potential—just be sure to check your hardware revision twice before hitting "Upload." Tune to a known accurate time signal (e
Disclaimer: Modifying firmware carries the risk of voiding warranties or damaging hardware. Always follow the specific instructions provided by the firmware developer.
Title: ATS20 Firmware Deep Dive: Which one gives the best performance?
Posted by: RadioRookie42
Hey everyone,
I’ve been tinkering with the ATS20 (Si5351 + Si4732 based SDR receiver) for a few months now. While the stock firmware is fine, I recently dove into the custom firmware options, and wow – it’s a completely different radio.
If you’re new to the ATS20, here’s a breakdown of the firmware scene I wish I had from day one.
Remove the four screws on the back. Carefully lift the PCB. Locate the 6-pin ICSP header (usually labeled MISO, MOSI, SCK, RESET, VCC, GND).
Because the community contributes to the code, you may encounter different firmware "flavors":
Enthusiasts have reverse-engineered and rewritten large parts of the ATS20 firmware, unlocking features the original designers never documented:
Some custom builds even add spectrum scope-like tuning indicators using just the existing LCD and clever timing tricks.
