radio-utils-emu

radio-utils-emu is a Software Defined Radio emulator that implements the OpenHPSDR Protocol 1 wire format for two target boards: the original Hermes and the Hermes Lite 2. It lets you simulate either radio on your network and test SDR applications like Thetis or deskHPSDR without physical hardware.

Features

Hardware emulation — presents itself on the LAN as either a Hermes (4 DDCs, Alex filters) or a Hermes Lite 2 (2 DDCs, N2ADR filter board, HL2 step attenuator).
Signal generation — Gaussian noise on every DDC at a configurable level.
Echo modes:
- Loop (--echo) — records the TX signal during PTT, trims silence, and loops it back forever on RX with a head/tail crossfade. Recordings persist across short PTT cycles (slow CW is preserved as one loop, not overwritten).
- Live (--echo-live) — feeds TX→RX in near real-time with a ~21 ms delay. Multiple concurrent transmitters on the same frequency additively mix, so the emulator can host a small "virtual band".
Multi-client — up to 32 simultaneous Protocol-1 sessions by default.
Telemetry — simulates forward/reverse power and supply voltage so client SWR meters animate.

Usage

Run the emulator pretending to be a Hermes Lite 2 on the LAN:

cargo run --release -p radio-utils-emu -- --radio hermeslite

Run it as a single-operator "virtual band" with live TX→RX feedback:

cargo run --release -p radio-utils-emu -- --radio hermeslite --echo-live

Any HPSDR-compatible client (Thetis, deskHPSDR, piHPSDR, your own code) will discover the emulator via UDP broadcast on port 1024.

Options

Flag	Description	Default
`--radio <TYPE>`	Hardware to emulate. One of: `hermes`, `hermeslite` (alias: `hermeslite2`).	(required)
`--mac <ADDR>`	MAC address as 6 hex bytes (separators optional, e.g. `00:1c:c0:a2:22:5e` or `001cc0a2225e`).	`02:AA:BB:CC:DD:EE`
`--noise <LEVEL>`	Noise floor amplitude as a fraction of full scale.	`1.26e-5`
`--echo`	Loop-mode echo: record TX during PTT, replay it on RX in a loop.	off
`--echo-live`	Live echo: TX→RX in real time, additively mixed across clients (mutually exclusive with `--echo` — `--echo-live` wins if both set).	off
`--bind <IP>`	Local IP to bind the UDP socket to. Useful when clients discover the emulator on the wrong interface (VPN, multi-homed host).	`0.0.0.0`
`--max-clients <N>`	Maximum concurrent Protocol-1 client sessions.	`32`
`-v`, `--verbose`	Enable `log::debug!` output.	off
`-h`, `--help`	Print the auto-generated help and exit.	—

Build

cargo build --release -p radio-utils-emu

See protocol.md at the workspace root for the wire- format reference this emulator implements.

License