The FLEX-8400 offers the latest direct sampling SDR technology at an economical price for the general HF/6m operator, yet it offers great performance for chasing DX and contesting.

Supporting Adaptive Predistortion

The FLEX-8400 model is designed for the Ham who wants to operate the radio exclusively as a server from PC, laptop, Maestro, Mac* or iOS* clients – whether local or remote.  Both models share the same game-changing band awareness, industry-leading phase noise performance, brick wall filters, and legendary audio performance to deliver you the most fun across a wide variety of operating styles.

With a PC, laptop, or Mac client you can utilize up to two 7 MHz spectrum/waterfall displays and independent receivers to revolutionize your view of the bands.  Its two receivers can be placed simultaneously on any band and mode with instant QSY between VFOs.  Digital mode operation is a dream with no sound cards, cables, or boxes needed.

FlexRadio’s industry-leading SmartSDRTM software offers compatibility across the entire FLEX-8000 Signature Series family to deliver continuous leveraged software enhancement. And you can use the latest SmartLinkTM technology to access your radio virtually anywhere from any SmartSDRTM compatible client with only a login and password – even your iPhone.

*Mac OSX SmartSDR and iOS SmartSDR clients are provided by third-party vendors

  • 100W PEP HF-6m operation
  • All modes/all bands
  • Integrated Remote Operation with Maestro, PC/Laptop, Mac, IPad® or iPhone®
  • 2 Independent Band / Mode Receivers
  • Full Duplex Cross-Band Operation
  • Transverter Port
  • Receive-Only Port
  • Direct Sampling SDR 122.88Msps – 16 bit
  • 115 dB 2kHz RMDR
  • >155 dB Dynamic Range
  • Optional Antenna Tuner
  • 10 MHz Reference Input
  • Integrated GPSDO Option for ultra high frequency precision and accuracy
  • Optional MARS/CAP/SHARES TX Expansion Module


  • Weight: 240 oz
  • Width: 18 in
  • Depth: 19 in
  • Height: 12 in


  • 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 Operation


  • 160m-6m Transmitter Output: 1-100W (25W AM)
  • Harmonic Suppression (Typ): <60 dBc
  • Transverter Ports: 1
  • Transverter Frequency Coverage/Power: 100kHz – 54 MHz/0 to +10 dBm
  • Optional Integrated Automatic Antenna Tuner Range: 3:1 SWR
  • Optional Continuous MARS/CAP Coverage with Extended Transmit Filter


  • 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 10MHz Reference Input
  • Power Supply Requirements 13.8 VDC +/- 15% (14 VDC Nominal)
  • Dimensions 6.74”H (17.1 cm) x 14”W (35.6 cm) x 13.25”D (33.7 cm)

1. RTTY and other digital modes use 3rd party software over DAX channels.

Plug & Play Remote1

  • 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-6400 you can operate your radio from almost anywhere! Just take an iPhone, iPad, Laptop, or Maestro with you and instantly connect to your radio using an Internet connection.

Best in Class Performance

  • 115db 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 Windows
  • SmartSDR for Mac2
  • SmartSDR for iOS2
  • SmartSDR CAT
  • DAX

1. SmartLink Remote Requires SmartSDR V2.x License or Later. Requires an Internet connection.
2. SmartSDR for Mac and SmartSDR for iOS are optional, 3rd party software for pay options.

FlexRadio does not charge your credit card until your order ships, but we do pre-authorize the full purchase price at the time you place your on-line order. If you choose to use PayPal as your payment method, your account will be charged immediately.

Due to the price class of a FLEX-8400, your order may exceed your credit card’s daily transaction limit resulting in your order not being completed. In these cases, you may either contact your credit card company and negotiate a different daily purchase limit -OR- you can call the FlexRadio Sales department at 512-535-4713 ext 1 to place your order over the phone where we will not pre-authorize order payment until time of shipment.

Resources for FLEX-8400 Signature Series SDR Transceiver