The uSDX transceiver is optimized and modified based on the Guido PE1NNZ open source project uSDX/QCX-SSB. The USDX is a shortwave QRP SSB/CW transceiver. With two OLED displays, it is compact in size and easy to carry. The automatic antenna tuner unit is adapted for QRP operation up to 10 watts. Features: Compact Size: It is compact in size, lightweight, portable and easy to use. 8 Bands Design: 3.5MHz; 5.3MHz; 7MHz; 10MHz; 14MHz; 18MHz; 21MHz; 29MHz. Emission Efficiency: higher than 85% ( 3.5MHz; 5.3MHz; 7MHz; 10MHz; 14MHz); higher than 80% (18MHz and 21MHz); For 29MHz, it's over 70%. PC Connection: Connected to a PC, using the FT8, JS8, FT4 and other digital mode software controls, supports CW automatic decoding. Free Upgrade: It can reach 3-5W power in 8 bands and can freely upgrade the PA module (TO-220). Stable Performance: High precise TCXO for KDS, with frequency accuracy better than 1PPM and frequency stability better than 0.5PPM. Independent Design: Independent core board, RF PA board, and ATU board to avoids its own signal interference. Selected Parts: All LPF parts use 100V C0G/NP0 capacitors, or use a LM4562 or LM833 or LT6231 op amp chip. Rich Interfaces: There are HEADPHONE, PTT OUT, MIC/PTT, SPK/MIC BNC antenna interfaces (with BCN-SL16 adapter, easy matching antenna). Specifications: Name: Transceiver Antenna Tuner Set Material: printed circuit board ATU (Automatic Antenna Tuner Unit): Maximum tuning inductance: 8.42µH Minimum tuning inductance: 0.05μH Maximum tuning capacitance: 1869pF Minimum tuning capacitance: 10pF Package size: 200 * 100 * 50mm / 7.87 * 3.94 * 1.97in Package weight: 1200g / 2.65lb uSDX_ATU System Functions: Full mode support: USB, LSB, CW, AM, Frequency Modulation All-digital and software-based software defined radio receive channels All-digital and software-based SSB transmit channels Receive attenuator: 0dB, -13dB, -20dB, -33dB, -53dB, -60dB, and 73dB DSP filter bandwidths: 4000, 2500, 1700, 500, 200, 100, and 50 Hz Receiving background noise: -135dBm at 28MHz (BW=200Hz) Receiver Front-End selectivity: Tuning frequency -45dB/decade roll-off ±2kHz SSB/carrier suppression: transmit, better than 45dBc; receive, better than 50dBc DSP functions: Automatic Gain Control (AGC), Noise Reduction (NR), Voice Triggered Xmit (VOX), RX Attenuator (ATT), TX Noise Gate, TX Drive Control, Volumes Control, dBm/S meter Three-Layer PCB: ATU-board PA-board: 8 band Mainboard Rear Panel Connector (JACK): 1. Headphone Jack (3.5 mm): Tips–Audio out Rings–Audio out Sleep–GND 2. MIC/PTT (Keys) Jack (3.5 mm): Tips–Mic input Rings–PTT Sleep–GND CW-KEYS INPUT MODE: Tips–DAH Rings–DIT Sleep–GND 3. SPK/MIC Jack (3.5 mm): Tips: SPEAKER Rings 1: MIC Rings 2: PTT SLEEVE: GND 4. PTT OUT Jack (3.5 mm): Tips–SSR output Rings–SSR output Sleep–GND Packing List: 1 * Main Unit 1 * 13.5VDC Power Adapter 1 * BNC Adapter 1 * BNC Cable 1 * Handheld Microphone 1 * Wrench Note: Note that there is no built-in battery or built-in speaker. External power supplys is required.