The SSB transmit stage is implemented entirely in a digital and software-based manner: at the heart, the ATMEGA328P is sampling the input audio and reconstructs an SSB signal by controlling the SI5351 PLL phase (through tiny frequency changes over 800 kbit/s I2C) and controlling the PA Power (through PWM on the key-shaping circuit). In this way a highly power-efficient class-E driven SSB signal can be realized; a PWM-driven class-E design keeps the SSB transceiver simple, tiny, cool, power-efficient, and low-cost (ie. no need for power-inefficient and complex linear amplifier with bulky heat-sink as often is seen in SSB transceivers).
The speaker is directly connected and driven by the ATMEGA. A digital mixer with a narrow low-pass window (2 kHz), and steep roll-off (-45 dB/decade) combined with an oversampling and decimating ADC are responsible for a processing gain, dynamic range, and alias rejection sufficient to handle weak and strong signal conditions (e.g. contests or listening on 40 m just next to broadcasting band).
The µSDX triband handheld transceiver’s unique form factor allows you to operate from anywhere. Press the XMIT button to transmit and talk straight to the built-in microphone while holding the radio in your hand. For extreme portability, you can use the optional external wide-range ATU, 12V battery, CW keyer, or handheld microphone.
The optional accessories allow this transceiver to be tailored to your needs, including the optional CW Keyer, Handheld Microphone, Data mode, CAT Control Interface, 100W Power Amplifier, Lithium Ion Battery, External ATU, light multiband HF portable antenna, Low Pass Filters Unit, micro PC unit. Please contact us if you need any of these.
Main Features and Specifications:
- LCD Display
- Built-in Speaker
- Built-in CW Decoder
- IRF MOSFET Power Transistors
- SMA Antenna Socket
- 13.8V Power Supply Provides up to 5 Watts PEP SSB Output Power
- Bands: 40, 20, and 15 m
- Modes: USB, LSB, CW, Digital
- DSP Filter: 4000, 2500, 1700, 500, 200, 100, 50 Hz
- Functions: Automatic Gain Control (AGC), Noise Reduction (NR), Voice Trigger, Voice Trigger Xmit (VOX), RX Attenuator (ATT), TX Noise Gate, TX Driver Control, Volume Control, dBm/S-meter
- SSB Reverse Sideband/Carrier Suppression Transmission: better than -45dBc, IMD3 (two tones) -33dBc, reception: better than -50dBc
- Open source firmware, built-in for Arduino IDE; allows experimentation, can add new functions, can share contributions through 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
- Fully digital and software-based SSB transmit-stage: samples microphone input and reconstruct an 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)
- Three independent switchable analog front-end receiver attenuators (0dB, -13dB, -20dB, -33dB, -53dB, -60dB, -73dB)
- Receiver noise level MDS: -135 dBm (200Hz BW) at 28MHz
- Receiver front-end selectivity: steep tuning frequency -45dB / ten times roll-off +/- 2kHz
- Blocking dynamic range: 20kHz offset 123dB, 2kHz offset 78dB
- CW decoder, straight/Iambic-A/B keyer
- VFO A/B + RIT and Split, and switch the corresponding relay band filter through I2C
- CAT support (Kenwood TS-480 subset), you can stream audio, press keys, and display text through CAT
- Compact Size: 50 x 20 x 80 mm
- Weight: approx. 180 g
|DC 9 – 15 VDC||External Power Supply Port|
Automatic CW Key Connection (A, B, Single Key)
External Power Amplifier, PTT Signal
|TTL||Serial Communication Port (CAT Control Commands Compatible with Kenwood TS-480)|
|Phone||Headphones (when connected mutes the internal speaker)|
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