FlexRadio has joined other leading amateur radio manufacturers in integrating digital signal enhancement techniques to reduce unwanted intermodulation distortion (IMD). Following the innovations of Apache Labs (ANAN) with their adaptive PureSignal technology, and Icom’s static Digital Pre-Distortion (DPD) feature for the IC-7610 and IC-7760, FlexRadio now introduces Adaptive Pre-Distortion (APD), also branded as SmartSignal, for their 8000 Series and the upcoming Aurora radios.
While the 6000 Series is not currently supported, FlexRadio has hinted at the possibility of a future hardware add-on that could extend APD capabilities to these earlier models.
Comparing Signal Enhancement Technologies
Three major signal improvement technologies are now available across top-tier radios:
- PureSignal (ANAN) and SmartSignal/APD (FlexRadio) are adaptive systems, constantly recalibrating based on real-time TX conditions.
- DPD (Icom) is a static system, calibrated once either during manufacturing or manually by the operator.
Adaptive systems offer broader flexibility, especially in dynamic operating environments, as they adjust automatically when changing frequencies or external conditions. Static systems, while simpler, do not adapt after initial calibration. Notably, adaptive systems such as ANAN’s PureSignal also support feedback from external power amplifiers, a capability not currently available with FlexRadio’s APD.
How to Enable and Use APD or DPD
- Icom Radios (IC-7610, IC-7760): With firmware version 1.4x and the latest SDR-Control app, users can activate DPD via a simple toggle in the Radio Settings menu. The IC-7760 is factory-calibrated, while IC-7610 users may need to run a manual calibration if not previously completed.
- FlexRadio (8000 Series): APD requires firmware version 3.9.x and SDR-Control app version 7.0.70 (iOS) or 2.9.70 (macOS). If available, an APD button appears in the TX panel of the Radio Control screen. A blue button indicates that APD is active; gray means it is off. Tapping toggles the feature.
Looking Ahead
FlexRadio’s move toward adaptive signal correction with APD marks a significant step in improving transmission quality. Future enhancements may include broader support and external PA feedback capabilities, aligning with the flexibility currently seen in ANAN’s PureSignal.
In any case, rest assured that the ham-radio-apps will continue to follow and support the latest technologies and features introduced by FlexRadio, Icom, Yaesu, Kenwood and Elecraft.