Hermes-Lite 2

Experimental

Hermes-Lite 2 support is experimental — it is not a supported radio family yet. Core receive and transmit work, but some controls, meters and radio-specific features are still incomplete. FlexRadio remains the supported target.

The Hermes-Lite 2 (HL2) is a low-cost, open-source SDR transceiver. It speaks HPSDR Protocol 1 (Metis) over Ethernet and, unlike a FlexRadio, ships raw IQ and runs no firmware DSP — all filtering, noise reduction and demodulation happen on your computer.

Connecting

1. Open Connect to Radio.
2. Choose the manual radio type Hermes-Lite 2.
3. The HL2 answers an HPSDR Protocol 1 discovery datagram on UDP/1024, so it is discovered automatically on the local network.

What works

• Four independent receivers, each with its own slice.
• SSB voice, CW/RTTY decoding, and AX.25 packet.
• Band switching with hardware filters.
• Manual notch filters.
• Noise blanking — the HL2 has no radio-side DSP, so the impulse blanker runs on the host, ahead of the demodulator, on the raw IQ.
• A real CW BFO — the passband skirt is centred on the CW pitch, so the receiver listens where the radio actually transmits.
• Host frequency calibration and per-radio state restore (including AGC mode and threshold, which survive a restart).
• Client-timed CW transmit with restart persistence.
• TX level control — the client's audio level (e.g. WSJT-X's Pwr slider) is honoured; the host speech ALC no longer overrides it.

How it differs from FlexRadio

• Host-modulated: the HL2 transmits whatever audio you send it, so the host does the modulation. This is the opposite of the networked Icom backend, which lets the radio modulate.
• No radio-side DSP: NR/ANF are not offered; the noise blanker and other processing run on the host.
• Raw IQ: there is no radio-generated spectrum; the panadapter is drawn from the IQ stream on your machine.

Limitations

• Experimental: not all meters, controls and radio-specific features are wired.
• The host does more work per slice than on a FlexRadio (IQ is processed locally).

See Supported Hardware for the full picture.