QMX Multi-band Multi-mode Transceiver

04/01/2025

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QMX: a feature-packed, high performance, 5-BAND 5W, CW and Digi-modes transceiver kit, including embedded SDR, 24-bit 48 ksps USB sound card, CAT control, synthesized VFO with TCXO reference.

The “QMX” (QRP Labs Multimode Xcvr): a feature-packed, high performance, five-band (80, 60, 40, 30 and 20m) 5W CW and Digi-modes transceiver kit, including embedded SDR receiver, 24-bit 48 ksps USB sound card, CAT control, synthesized VFO with TCXO reference. QMX may be used in CW modes standalone, or with a single USB cable to a PC for digi mode operation. QMX also incorporates standalone CW, FSKCW and WSPR beacon functionality (no PC connection required).

QMX transmits a SINGLE SIGNAL on FSK signal modes, it is not an SSB modulator with associated unwanted sideband and residual carrier, or intermodulation due to amplifier non-linearity. QMX outputs a pure single signal. QMX is, in the first firmware releases, suitable only for CW and single tone FSK modes, which covers the majority of digital modes in use today. This includes everything in WSJT-X, JS8Call, some fldigi modes e.g. RTTY, Olivia and more. QDX is not suitable for phase shift keyed modes such as PSK31 or modes involving multiple concurrent tones such as WinLink,

The Optional enclosure is black anodized extruded aluminium, very sturdy and elegant. The enclosure size is 95 x 63 x 25mm without protrusions. The front and rear panels are drilled and cut to match the QMX PCB with laser-etched lettering. The enclosure includes four self-adhesive feet and end panel securing screws.

QMX is available in kit or assembled versions.

QMX Transceiver

List of features:

80, 60, 40, 30 and 20m
CW and FSK Digi modes
All features of QCX-mini (VFO A/B/Split, RIT, Message and frequency memories, beacon, keyer, etc)
4-5W output at 9V supply (can be built for 4-5W at 12V supply)
SWR bridge built in
Single signal digi mode transmission (zero unwanted sideband, zero residual carrier, zero intermodulation distortion)
Solid-state band switching and transmit/receive switching under CAT control
High performance embedded SDR SSB receiver with 60-70dB of unwanted sideband cancellation
Built-in 24-bit 48ksps USB sound card
Built-in USB Virtual COM Serial port for CAT control
Si5351A Synthesized VFO with 25MHz TCXO as standard
Easy to build single-board design, Professional quality 6-layer, through-hole plated, silk-screen printed PCBs
All SMD components factory assembled
Connectors: 2.1mm power barrel connector, USB-C (for audio and CAT control), BNC RF input/output, 3.5mm jacks for audio out, paddle/GPS/mic/PTT in, and PTT out
Built-in test signal generator and testing tools
Switched mode regulators Receive current 80mA, Transmit current 1.0-1.1A for 5W output with 9V supply (around 0.7A for 5W with 12V supply).
Optional aluminium extruded cut/drilled/laser-etched black anodized enclosure