USDR is optimized and modified based on the open source work uSDX/QCX-SSB. This is a shortwave QRP SSB/CW transceiver. The ultra-small size makes it easy to carry for outdoor use. It adopts 1602N LCD screen, built-in speakers. Support to connect to PC and use FT8, JS8, FT4 and other digital mode software control, support CW automatic decoding. 8 band coverage 80m/60m/40m/30m/20m/17m/15m/10m – Excellent PCB layout design in line with high-frequency circuit design principles to ensure excellent performance – Can reach 3-5W power in 8 bands and reserve TO-220 package pads required for upgrades – High emission efficiency, 80m/60m/40m/30m/20m efficiency is higher than 85%, 17m/15m efficiency is higher than 80%, 10m efficiency is higher than 70% – High-precision for KDS brand TCXO, frequency accuracy is better than 1PPM, frequency stability is better than 0.5PPM – Independent core board and RF board to avoid own signal interference. Ultra-small size: 83 x 38 x 124mm(excluding protruding parts) – Rich interfaces (CAT, PTT OUT, MIC/KEY, K-head microphone) – All LPF parts use 100V C0G/NP0 capacitors – Use original genuine Omron magnetic latching relay – Use original genuine LM4562 or LM833 op amp chip – Built-in speaker with cavity – BNC antenna interface. 99MHz with loss in performance – Open source firmware, built with IDE for Arduino; allows experimentation, new features can be added, contributions can be shared via Github, software-complexity: 2000 lines of code – Software-based VOX that can be used as fast Full Break-In (QSK and semi-QSK operation) or assist in RX/TX switching for operating digital modes (no CAT or PTT interface required), external PTT output/PA control with TX-delay – Simple to install modification with 8 component changes and 8 wires – Lightweight and low-cost transceiver design: because of the EER-transmitter class-E stage it is highly power-efficient (no bulky heatsinks required), and has a simple design (no complex balanced linear power amplifier required) – Fully digital and software-based SSB transmit-stage: samples microphone-input and reconstruct a SSB-signal by controlling the phase of the SI5351 PLL (through tiny frequency changes over 800kbits/s I2C) and the amplitude of the PA (through PWM of the PA key-shaping circuit) – Fully digital and software-based SDR receiver-stages (optionally): samples I/Q (complex) signal from Quadrature Sampling Detector digital mixer, and performs a 90-degree phase-shift mathematically in software (Hilbert-transform) and cancels out one side-band by adding them – Three independent switchable analog front-end receiver attenuators (0dB, -13dB, -20dB, -33dB, -53dB, -60dB, -73dB) – Receiver Noise level MDS: -135 dBm at 28MHz (in 200Hz BW) – Receiver Front-end selectivity: steep -45dB/decade roll-off +/-2kHz from tuned-frequency – Blocking dynamic range: 20kHz offset 123dB, 2kHz offset 78dB – CW decoder, Straight/Iambic-A/B keyer – VFO A/B + RIT and Split, and corresponding relay band-filter switching via I2C – CAT support (TS480 subset). 1 x Transceiver – 1 x Mic. (Note: it’s not including Built-in battery).
