https://github.com/kholia/DDX
Direct Digital Transceiver. It's likely a shortwave digital mode radio based on the ADX project, which is derived from WB2CBA (but both ADX and ADX-S do not support the 6m band; as mentioned below). I think this project could offer some cost-effective long-distance weak signal communication options for amateur radio operators with a Class A license.
Currently, there are several branches of DDX under development simultaneously (DDX-1 ~ DDX-4, and the "next generation" DDX-EVO), with DDX-1 R2.50 and DDX-1-R1.10 being the most actively submitted versions. The design power for DDX-1 R2.50 is 10W, and for DDX-1-R1.10 it is 5W.
Google Translate Features (5W Version):
Single USB-C cable for handling audio + CAT control.
Achieve true 5W output across all HF bands. It can even output 1 W in the 50 MHz band.2 W! (Just needs a receiver for the 6m band). [Note: However, no data is provided regarding harmonics/spurious emissions. We hope everyone can collaborate to DIY and test.]
The robust PA can handle opening, short-circuit, and severe SWR conditions (up to 1:10 SWR), as demonstrated in testing. We intentionally used an un-tuned antenna for stress testing, and it still managed DX communication (although this is not recommended).
The VFO is incredibly stable, and will not drift even under exposed conditions. Yes – it works perfectly for receiving 28 MHz WSPR signals.
Reliable transmit and receive switching based on DPDT relays
Support for switchable BPF (Band-Pass Filter), which can eliminate interference from BCI and other sources (tested) against OTH radar + 100 kW AM station, enabling visual detection at close range.
Without a ring-shaped inductor (assuming an external LPF bank is being used);-)
IRF510 final: Keep it cool like a cucumber (Class D operation) – A small heatsink is more than sufficient.
Avoid issues related to the "audio counting" method used. DDX-1 provides bit-perfect, deterministic TX output.
It works perfectly with the "FT8 Radio" application.https://github.com/kholia/DigitalRadioReceiverSupport/). The "FT8 Radio" application provides excellent real-time FT8 decoding performance (currently, the native MCU decoder's performance is not ideal). The application can decode over 35 stations at once, and even large screens will quickly fill up – this demonstrates the receiver's performance (with BPF)!
Supports highly automated assembly from JLCPCB (all necessary files are in a single GitHub repository)
The DDX-1 comes with firmware that has a free and open-source AGPLv3 license.
(It) doesn't require calibration. Simply pick up the DDX-1, and it will be ready to use.
Low cost (our BOM estimate is between $20 and $30)
We conducted multi-day stress tests using WSJT-Z.
This Indian (?) guy, Kholia, also has other projects, such as the FT8 beacon (Pico-FT8-TX), which is a power amplifier for shortwave radio stations (HF-PA-v10), and a shortwave antenna that can be installed on a balcony (HF-Balcony-Antenna-System). It also includes a solar-powered FT8 decoder with WiFi support via Raspberry Pi Pico W (SunshineFT8).
闽ICP备2021006864号-7
闽公网安备35020602002794号