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Version: 26.10.1

Hermes-Lite 2

Status

Status: Experimental · Applies to: Hermes-Lite 2

AetherSDR can operate a Hermes-Lite 2 (HL2) over openHPSDR Protocol 1. Support is experimental: the radio receives and transmits, but FlexRadio remains AetherSDR's supported target (see Supported Radios). An EXPERIMENTAL badge shows in the title bar while an HL2 is connected.

The HL2 has no on-board DSP, so AetherSDR does the demodulation, filtering, AGC, noise blanking and transmit modulation on your computer, using WDSP.

Where to go next​

Setup​

Connecting​

The HL2 is found automatically on your LAN: open File → Connect to Radio... → On This Network, select it and click Connect Selected Radio.

Across a VPN or another subnet, use Connect by IP with Radio type: set to Hermes-Lite 2 (see Manual Connection).

  • Connect to last radio on start up works with the HL2.
  • Nickname: right-click the radio in the list → Set Nickname… / Clear Nickname (no need to connect), or Settings → Radio Setup... → Radio → Nickname: while connected. HL2 nicknames are stored on this computer, keyed by the radio's MAC address.
  • The very first connect on a computer spends a while planning its DSP filters; the app stays responsive while it does. The result is saved, so later connects are quick.
  • The status bar shows the gateware version.

Board variant and hardware: HL2 Hardware​

Settings → Radio Setup... → HL2 Hardware describes the physical radio. It appears while an HL2 is connected, and the settings are stored against that radio.

GroupControls
Local AudioCodec: None — plain Hermes-Lite 2, AK4951 — HL2+ companion board, or SquareSDR 2 — codec on the mainboard. A board with a codec can play receive audio on the radio's own speaker; Speaker level: sets it.
Dither BitDither bit and Random bit. On some variants the first box is relabelled to what that board uses the line for (internal loudspeaker or band-voltage output).
Companion Filter BoardBoard: None — nothing on J16, N2ADR — receive and transmit, or N2ADR — transmit only. Receive through the N2ADR 3 MHz high-pass adds the AM-broadcast high-pass on receive (80 m to 10 m). Choose None only when nothing is fitted, because then nothing filters the transmitter's harmonics.
Reference Clock and TunerExternal 10 MHz reference at CL1 locks the radio to a reference such as a GPSDO instead of its crystal. CL1 expects a 3.3 V logic-level clock: pad a typical 5 V GPSDO output with at least 6 dB of 50 Ω attenuation. Lock is not read back. Antenna tuner driven by the HL2 gateware raises the tune request during TUNE for an AH-4-protocol ATU; leave it off for a tuner on the N2ADR IO board.

The HL2 IO board's amplifier control follows the band.

Frequency calibration​

Settings → Radio Setup... → Calibration corrects the HL2's crystal. It appears only on radios that cannot calibrate themselves.

  1. Let the radio warm up for 15 minutes.
  2. Pick a Reference: (WWV/WWVH 2.5–25 MHz, CHU 3.330 / 7.850 / 14.670 MHz, or GPSDO / signal generator (custom) with its frequency). Attenuate a GPSDO by at least 30 dB.
  3. Zero-beat the reference with normal tuning, then click Calibrate from current VFO.
  4. Fine-tune with Trim: − / + (steps of 0.1, 1 or 10 Hz at 10 MHz), or type the Error: in ppb (±50,000 ppb). Reset returns to 0.

One value corrects every band, receive and transmit. It is stored per radio (by MAC), so a second HL2 does not inherit it. While External 10 MHz reference at CL1 is on, the manual calibration is zeroed and disabled.

Receivers and Panadapters​

  • Up to four receivers (A–D), each with its own slice, panadapter, audio and S-meter. Add one with Tools → Add Panadapter...; close its pane to remove it.
  • The receivers share one converter, so the span (sample rate), LNA gain, band and antenna are radio-wide. Mode, passband, AGC and frequency are per receiver.
  • Span snaps to 48, 96, 192 or 384 kHz. Four receivers run up to 192 kHz, three at 384 kHz. Use low bandwidth mode caps the span at 96 kHz. Only the pane holding the TX slice (otherwise the first docked pane) has live span buttons; the others are dimmed with the reason.
  • Band buttons switch the hardware filters and preamp as well as the frequency.
  • Spots from the DX cluster, RBN, WSJT-X, POTA and manual entry are drawn on the panadapter. Right-click a spot → Remove Spot.
  • Display: FFT AVG really averages (about 10 ms per step); at 0 the trace is unaveraged. Manual Black Level and waterfall NB Blank work. WtrFall Rate is a rate in rows per second. FFT FPS and the dBm range are remembered across restarts.
  • Tools → Wideband Bandscope... shows one raw record of the whole converter band (0 to 38.4 MHz) on demand.

RF Gain and the dBm Scale​

  • RF gain is the HL2's LNA, −12 to +48 dB. It is remembered per band; a band you have not visited starts at +20 dB.
  • The dBm scale is derived from the LNA setting (full scale is +3 dBm at 0 dB LNA). It is not a calibrated measurement.
  • Auto RF gain adjusts the LNA from the measured wideband headroom, in 6 dB steps, across the full range. If it cannot arm, the reason appears on the checkbox and in a notice.
  • CAT L RF / l RF (rigctl) drive the panadapter RF gain across the same range; 0.5 is +18 dB.

Upgrading from an older version:

  • A band you have not visited comes up at +20 dB LNA on every profile. A profile that carried a stuck lower value comes up hotter (26 dB in the reported case) on unvisited bands. Visited bands keep their gain.
  • At the default +20 dB LNA, a given squelch level gates 32 dB higher than before. Where Auto squelch is not available, a slice in Auto drops to Manual at its manual level.
  • Selecting DIGU or DIGL now turns AGC off on that receiver. A DIGU/DIGL band-stack bookmark saved earlier can still restore its saved AGC mode.
  • A profile that ticked Auto RF gain (always refused before) now arms on its first connect, and runs in 6 dB steps.

Receive​

  • Latency: outside CW the receive filter runs at minimum phase, so audio returns 44 ms after an unmute. In CW, onset is 85 ms; a notch or a passband under 100 Hz lengthens the filter.
  • After you unkey, receive stays muted through the transmit/receive turnaround, so you don't hear the PA's own carrier.
  • S-meter reads WDSP's average level. It holds steady across key-down and unkey.
  • AM and SAM audio is DC-blocked and clean.
  • CW: the passband is centred on the signal marker (a real BFO at your CW pitch).

Squelch​

The SQL button works per mode family:

  • FM: FM squelch.
  • AM, SAM, DSB, LSB, USB: a level squelch with a threshold map measured on the HL2. It tracks RF gain dB for dB.
  • CW and data modes: no squelch.

The panadapter SQL line and Auto squelch use the HL2's own scale.

AGC and APF​

  • AGC mode and threshold are remembered across restarts.
  • AGC off: the AGC-T slider sets a fixed gain, 4–64 dB (10 dB by default). The AGC-off level is remembered per receiver.
  • Selecting DIGU or DIGL turns AGC off on that receiver. Raise the AGC-off level if data audio is too quiet.
  • APF, the CW audio peaking filter, is centred on your CW pitch. Its toggle and level are in the P/CW pane.

RIT and XIT​

RIT and XIT work per receiver, ±9999 Hz. When transmit passes to another receiver, that receiver's XIT applies.

Notches and noise blanker​

  • Manual notches: right-click the panadapter → Add TNF at X MHz. Drag a notch sideways to move it and up or down to change its width; right-click it to remove it. Notches keep tracking as you tune. See TNF (Tracking Notch Filters).
  • NB runs WDSP's impulse blanker on the raw IQ, ahead of the demodulator. It is held during transmit.
  • Client-side noise reduction works as on any radio; see DSP Noise Mitigation.

Transmit​

  • SSB voice uses WDSP's TXA modulator. The EQ, PROC, TX low/high cut, eSSB, ALC and compression gauges act on the HL2.
  • The Mic Level slider is the transmit level. The ALC only ever reduces. The Phone panel shows the ALC Gain the radio reports.
  • Data: WSJT-X and similar programs work over the TCI Server. Their power slider changes RF output, and the speech ALC does not raise client audio. The WSPR beacon defaults to −3 dBFS and is not moved by the mic slider.
  • CW is keyed with host-timed edges, with sidetone. CW settings are restored after a restart.
  • TUNE keys at Tune Power, and moving Tune Power during a tune changes the carrier.
  • Max Power: Settings → Radio Setup... → Transmit → Max Power shows the HL2's rated watts, read-only. The power gauge uses a 5 W scale, and forward power reads near PEP on speech.
  • RF power slider: the radio has 16 drive steps, so several slider positions do nothing and then one position adds about 1.25 dB.
  • Modes that refuse to transmit: AM, SAM, DSB, FM, NFM, WBFM and DRM refuse MOX and TUNE, because the HL2 modulator is SSB only. A mode the HL2 cannot demodulate is refused everywhere.
  • TX drive and LNA gain are remembered per band.

Other Features​

  • CW, RTTY and AetherClock decoders, and the QSO recorder.
  • AX.25 packet with AetherModem (APRS, KISS TNC, terminal and mailbox).
  • Memory channels, stored on this computer in the bank shared by radios without memory slots. See Memory Channels.
  • Tools → Radio Health... shows link, temperature, supply, PA current, gateware and the transmit voice chain.
  • Connection health in the title bar, status bar and network statistics.

Reference​

Not available on the HL2​

  • DAX, SmartLink or Multi-Flex.
  • The status-bar CWX, DVK and FDX toggles are hidden: the HL2 has no radio-side CW text keyer, voice keyer or full duplex.
  • FM repeater duplex and CTCSS encode.
  • Controls the HL2 cannot honour are dimmed with their reason, or refuse with a notice.

Known issues​

  • Receivers B, C and D do not come back after you restart AetherSDR; only receiver A reconnects (#5777).
  • Graphic EQ band values are lost when you restart AetherSDR (#5611).
  • Keying with the HL2's hardware PTT jack does not show as transmit in AetherSDR, and does not carry host audio (#5998).
  • TX Delay and the other fields under Settings → Radio Setup... → Transmit → Timings do not hold a value and are not applied to the HL2 (#5370).
  • Each over starts with about 100 ms of keyed silence before your audio is transmitted (#6052).
  • Changing CW break-in or its delay shows a "nothing was sent to the radio" notice, although both settings take effect (#6153).

Troubleshooting​

The first connect takes a long time​

On a computer's first connect, AetherSDR plans the HL2's DSP filters.

  1. Wait for it to finish; the app stays responsive meanwhile.
  2. Later connects reuse the saved result and are quick.

Span buttons are dimmed on a panadapter​

The receivers share one sample rate, and only one pane controls it.

  1. Change the span from the pane that holds the TX slice (or, if none does, the first docked pane).
  2. If the span will not go above 96 kHz, untick Use low bandwidth mode in the Connect to Radio window and reconnect.

Data-mode audio is too quiet​

DIGU and DIGL turn AGC off on that receiver, so the fixed AGC-off gain sets the level.

  1. Raise the AGC-T slider on that receiver (4–64 dB, 10 dB by default).

MOX or TUNE is refused​

The HL2 modulator is SSB only, so AM, SAM, DSB, FM, NFM, WBFM and DRM refuse to transmit.

  1. Switch the slice to USB, LSB, CW or a data mode before keying.

The Calibration controls are disabled​

External 10 MHz reference at CL1 is on, which zeroes and disables the manual calibration.

  1. Open Settings → Radio Setup... → HL2 Hardware.
  2. Untick External 10 MHz reference at CL1 if you want to calibrate the crystal instead.

Moving the RF power slider changes nothing​

The HL2 has 16 drive steps, so several slider positions fall on the same step.

  1. Keep moving the slider; the next step adds about 1.25 dB.

See also​