Airspy HF+ Discover achieves excellent HF performance by means of a low-loss preselection filter, high linearity LNA, high linearity tunable RF filter, polyphase harmonic rejection (HR) mixer hat rejects up to the 21st harmonic and multi-stage analog and digital iF filtering.

The 6 dB-stepped AGC gain is fully controlled by the software running in the DSP which optimizes the gain distribution in real time for optimal sensitivity and linearity. Harmonic rejection is a key issue in wide band HF receivers because of the large input signal bandwidth of the input signal.