FlexRadio 8400M HF/6-Meter Signature Series SDR Transceivers feature the latest direct sampling SDR technology, paired with a high-resolution display and ergonomic controls. The FLEX-8400M combines all the capabilities of the FLEX-8400 with a stunning 8-inch 1920×1200 IPS WUXGA touchscreen and intuitive controls, delivering high-performance SDR functionality in a traditional radio interface. Unmatched band awareness comes from the integrated display, while support for external monitors at 1900×1200 resolution enhances spectral visibility.

Designed with input from top contest and DX operators, the symmetrical and independent dual VFO controls are strategically placed to maximize productivity across all operating styles. Fully self-contained, the transceiver requires no PC, network, or steep learning curve—just plug in and operate.

When connected to a PC, laptop, or Mac client, users can access up to two 7 MHz spectrum/waterfall displays and independent receivers, transforming how bands are viewed. Both receivers can operate simultaneously on any band and mode, with instant QSY between VFOs. Digital mode operation is streamlined—no sound cards, cables, or external boxes needed.

FlexRadio’s industry-leading SmartSDR™ software ensures compatibility across the entire FLEX-8000 Signature Series, enabling continuous software enhancements. With SmartLink™ technology, remote access is simple—just log in from any SmartSDR-compatible client, including an iPhone.

Key Features

Integrated High-Resolution Touch Display with External Monitor Support: The FLEX-8400M features a stunning 8-inch 1920×1200 IPS WUXGA touchscreen, delivering exceptional band awareness and intuitive control. For expanded spectral visibility, it also supports external monitors at 1900×1200 resolution via HDMI—ideal for detailed spectrum and waterfall analysis.

Dual Independent Receivers with Full Band Flexibility: Operate with confidence using two fully independent receivers, each capable of tuning any band and mode simultaneously. With up to two 7 MHz spectrum/waterfall displays and instant QSY between VFOs, the 8400M is optimized for contesting, DXing, and digital modes—no sound cards or external boxes required.

True Plug-and-Play Remote Operation with SmartLink™: Thanks to SmartLink™ technology, you can operate your FLEX-8400M from virtually anywhere using a Maestro, Mac, iPad, iPhone, or laptop—no complex setup or networking required. Just log in and go, whether you're across the room or across the world.

What’s in the box:

• (1) Flex-8400M

• (1) FHM-3 Hand Mic

• (1) DC Power Cable

• (1) Ethernet Cable)

• (1) Quick Start Guide

• (1) GNNS/GPS Antenna

Additional Features and Specifications:

Transmitter

• Band Coverage: 160-6m

• Power Output: 100W (25W AM)

• Harmonic Suppression (Typ): <60 dBc

• Transverter Ports: 1

• Transverter Frequency Coverage/Power: 100 kHz – 54 MHz/0 to +10 dBm

• Optional Integrated Automatic Antenna Tuner Range: 3:1 SWR

• Optional Continuous MARS/CAP Coverage with Extended Transmit Filter

Receiver

• Independent Band/Mode Receivers (Max): 2

• ½ kHz Reciprocal Mixing Dynamic Range (RMDR): 110/115 dB

• ADC Bits/Sampling Rate: 16/122.88 Msps

• Frequency Coverage: 30 kHz-54 MHz

• Amateur Band Preselectors: 3rd Order

• Cable-less Digital Audio (DAX/DAX IQ) Channels: 2/2

• Receive Only Ports (Base/Including XVTR Port): ½

• Full Duplex RX/TX Cross-band Operation

General

• Modes: SSB, CW, AM, SAM, FM, RTTY, DIGITAL

• Integrated Remote Operation (SmartLink)

• Maestro, PC, Mac, iPhone® and iPad® Client Options

• Frequency Stability: (0⁰C – 50⁰C) 0.5ppm (TCXO)

• Optional GPS Disciplined Oscillator: (5 x 10-12 Over 24 Hours)

• External 10 MHz Reference Input

• Power Supply Requirements: 13.8 VDC +/- 15%, 25A Continuous

• Antenna Ports: 2 UHF SO-239 female

• Dimensions: (WxHxD) 14.0 x 6.74 x 13.25 in. (35.6 x 17.1 x 33.7cm)

Spectrum / Waterfall

• Integrated Touch Panel Display Size Diagonal: 8-inch (8400M)

• Integrated Display Resolution: 1920 x 1200

• External Display Resolution/Connection: 1920×1200 / HDMI (8400M)

• Spectrum / Waterfall Displays (Max): 2

• Spectrum /Waterfall BW (Min/Max): 5 kHz to 7 MHz

• Spectrum Dynamic Range (Max Zoom In): >145 dB

• Spectrum Resolution Bandwidth (Min): 5.58 Hz/px

Additional Features

• No PC required to operate the FLEX-8400M

• 8-inch 1920 x 1200 IPS Display

• Up to two independent receivers

• Up to two 7 MHz spectrum displays

• Optimized workflow

• Ergonomically spaced / single-function controls

Plug & Play Remote

• No complex setup required

• Operate anywhere, any time

• Use a Maestro, Mac, iPad, iPhone or Laptop

• Across the country or across the world

• Anywhere, Anytime, From Any of These Devices:

• With SmartLink and a FLEX-8400M, you can operate your radio from almost anywhere! Just take an iPhone, iPad, Laptop, or Maestro with you and instantly connect to your radio with virtually no setup required.

Best in Class Performance

• 115 db RMDR

• No listening fatigue

• Ultra-low phase noise

• Full Break-in QSK CW

• Brick Wall Filters

• Stunning transmit audio

Backed by an Amazing Suite of Software

• SmartSDR for the M Model Radio

• SmartSDR for Windows

• SmartSDR for Mac *3

• SmartSDR for iOS *3

• SmartSDR CAT

• DAX

Important Notes:

1 – A PC is required for use of 3rd party software such as loggers and digital mode programs.

2 – SmartLink Remote requires SmartSDR v2.x license or higher. Requires and Internet connection.

*3 – SmartSDR for Mac and SmartSDR for iOS are optional, 3rd party software for pay options.