FlexRadio FLEX-6700 firmware v4.3.16

Page 1 | Copyright 2026 FlexRadio, Inc. | SmartSDR v4.3.16 Release Notes | SmartSDR+ v4.3.16 Release Notes Version Release Date Release Theme/Title 4.3.16 2026-10-13 AutoDX, Auto AGC-T, DSP Controls - Advanced and Noise Floor Range Adjustment SmartSDR Basic™ and SmartSDR+™ v4.3.16 is an Early Access software and firmware release for Aurora™, FLEX-8000™, and FLEX-6​000™ series SDRs, as well as Maestro™.

This version supersedes all previous SmartSDR releases and is available to all users.

Access to new features introduced in this release is limited to SmartSDR+ Early Access feature license holders unless otherwise noted.

Important Release Information Before upgrading, please review all sections marked as IMPORTANT for upgrade prerequisites and other critical information.

There are multiple important notices associated with SmartSDR v4.3.16.

You should understand these changes before upgrading from a previous version of SmartSDR.

Please open a HelpDesk support ticket if you have questions.

Important Notice: SmartSDR v4.2.18 introduced a new software architecture with updated DAX and FlexVSP drivers.

Leaving older versions on your PC may cause installation conflicts or degraded performance.

If you are running SmartSDR v4.1.5 or earlier, we strongly recommend completely uninstalling all previous versions of SmartSDR, including the DAX and FlexVSP drivers, before upgrading to SmartSDR v4.3.16.

If you are running v4.2.18 or later, you can skip this notice.

For detailed uninstall and installation instructions, see the HelpDesk article "How to Install SmartSDR v4.2.18." When following those steps, substitute v4.3.16 for v4.2.18.

Important Notice: The DVK Function Key memories in Maestro/M will be deleted as part of the v4.3.16 upgrade, due to resolving several problems in the v4.2 code that have since been fixed.

Migration would have carried the problems forward.

New v4.3.16 Features at a Glance Feature Needed Feature License Supported Radio Models AutoDX (ADX) SmartSDR+ (Early Access) FLEX-8000 Series, Aurora Auto AGC-T SmartSDR+ (Early Access) FLEX-6000 Series, FLEX-8000 Series, Aurora Expanded DSP Algorithm Controls SmartSDR+ (advanced parameters) Basic (on/off and level settings) All models (NRF, NRS, and RNN: FLEX-8000 Series and Aurora only) Noise Floor Range SmartSDR+ FLEX-8000 Series, Aurora CW Profiles SmartSDR Basic FLEX-6000 Series, FLEX-8000 Series, Aurora PTT Override SmartSDR Basic FLEX-6000 Series, FLEX-8000 Series, Aurora Toggle Breakin F-Key SmartSDR Basic M-Models and radios connected to a Maestro NTP Time Sources SmartSDR Basic FLEX-8000 Series, Aurora Confirm Exit (CAT and DAX) SmartSDR Basic All models (SmartSDR CAT and DAX) Page 2 | Copyright 2026 FlexRadio, Inc. | SmartSDR v4.3.16 Release Notes | SmartSDR+ v4.3.16 New SmartSDR+ and Basic Features: As noted below, radios licensed for SmartSDR+ will gain access to the new SmartSDR+ features approximately 30 days after this Early Access release, with a follow-up release of SmartSDR v4.3.

Feature Description AutoDX (ADX) SmartSDR+ Early Access.

FLEX-8000 Series and Aurora radios AutoDX decodes received CW to on-screen text and can automatically work a split pile-up on your behalf.

Enter the DX callsign and your exchange, and AutoDX listens for the DX station, calls when it hears the selected trigger, sends your exchange when the DX station comes back to you, and counts the completed QSO.

Decoded traffic stays on screen, and keying the paddle or CWX hands control back to you instantly.

• Requires two CW Slices on different frequencies (one TX enabled) and a callsign set on the radio.
• Adjustable TX delay, reply delay, call attempts, give-up timer, and automatic restart.
• Built-in CW decoder with WPM, SNR, and lock indication, usable with or without AutoDX enabled.
• Available in SmartSDR for Windows (ADX window) and on Maestro and M-Models (AUTODX panel and Toggle AutoDX F-Key).

Operating Instructions: How to Use the AutoDX (ADX) Feature Auto AGC-T SmartSDR+ Early Access.

FLEX-6000 Series, FLEX-8000 Series, and Aurora radios.

Auto AGC-T sets the AGC Threshold for each Slice automatically from a long-term measurement of the adjacent noise floor, keeping the threshold well set as you change bands and antennas and as band conditions change.

It ignores short-term transients such as lightning crashes.

Auto AGC-T is off by default and is enabled per Slice; adjusting AGC-T by hand returns the Slice to manual control.

Operating Instructions: How to Use the Auto AGC-T Feature Expanded DSP Algorithm Controls Advanced parameters: SmartSDR+.

All models except where noted.

On/off and levels: SmartSDR Basic.

The noise mitigation algorithms now have a dedicated DSP Controls Panel, opened from the Slice menu.

The panel provides an on/off button and a level slider for most of them.

An Advanced menu adds per-algorithm parameters (such as delay, window, taps, leakage, and tone thresholds) for NR, NRL, NRF, ANF, ANFL, and ANFT.

The panel shows only the algorithms that apply to the current mode, and Reset All returns parameters to their defaults.

Radios that received the v4.0.1 algorithms also receive these controls, including radios whose SmartSDR+ license has since expired.

Operating Instructions: How to Use the DSP Controls Panel Page 3 | Copyright 2026 FlexRadio, Inc. | SmartSDR v​4.3.16 Release Notes | Noise Floor Range Adjustment SmartSDR+.

FLEX-8000 Series and Aurora radios.

Noise Floor Range enhances Relative Noise Floor Scaling by setting how far the measured noise floor may move before the Panadapter repositions, from 0 to 10 dB in 0.5 dB steps (default 1.5 dB).

Increasing the range reduces the display oscillation that can occur at high zoom levels.

The setting is in the Display menu and applies to all Panadapters.

Radios that received Relative Noise Floor Scaling in v4.0.1 also receive this feature.

Operating Instructions: How to Set Noise Floor Range CW Profiles SmartSDR Basic.

FLEX-6000 Series, FLEX-8000 Series, and Aurora radios.

A new CW profile type joins the Global, Transmit, and Microphone profiles.

CW profiles store keyer settings (pitch, speed, iambic mode, paddle swap, break-in, and more), sidetone settings, and CWX settings including macros.

Profiles can be created, loaded, switched from the TX panel or TX menu, auto-saved, and imported or exported.

Operating Instructions: How to Use CW Profiles PTT Override SmartSDR Basic.

All models.

PTT Override selects which audio source a hardware PTT (RCA or footswitch, ACC, or mic jack) puts on the air.

When enabled, hardware PTT transmits the last used analog mic input even while DAX or remote TX audio is selected.

• Behavior change: Before v4.3, hardware PTT always switched to the analog mic input. PTT Override is now disabled by default, so hardware PTT transmits the selected source. Enable PTT Override to restore the earlier behavior.

Operating Instructions: How to Set PTT Override Toggle Breakin F-Key SmartSDR Basic.

M-Models and any radio connected to a Maestro.

A new Toggle Breakin F-Key action turns CW Breakin on and off with one key press.

The F-Key LED follows the Breakin state.

Operating Instructions: How to Assign the Toggle Breakin F-Key NTP Time Sources SmartSDR Basic.

FLEX-8000 Series and Aurora radios; configured from SmartSDR for Windows.

A new NTP tab in Radio Setup lets you configure up to 10 NTP servers, pools, or peers for the radio clock, mark preferred sources, and monitor each source’s status, stratum, and reachability.

The radio ships with a default Debian NTP pool, which is re-created automatically if no sources are configured.

When a GPSDO is installed and delivering time, it takes priority, and the NTP sources act as a fallback.

Operating Instructions: How to Configure NTP Time Sources Confirm Exit for SmartSDR CAT and DAX SmartSDR Basic.

SmartSDR CAT and SmartSDR DAX.

A Confirm Exit setting in the CAT and DAX Settings menus makes the close confirmation dialog optional.

It is on by default, so existing behavior is unchan