Virtual Transmitter

RF SPECTRUM simulated - generated in software

Span Band markers

MPX COMPOSITE

0-59 kHz

PROGRAM AUDIO

GR 0.0 dB

-90.0

-60-40-20-100

RDS MONITOR

0 groups/s

PSHOT Z100

RTTHE REAL PARTY STATION

PI0x1FCA

PTYTop 40

FlagsTP:0 TA:0

Group0A

STREAM

IDLE

Playlist-

Listeners-

Next-

Buffer

0%

Source-

Errors-

HD SIMULATION

SIMULATED HD RADIO

Not an official or licensed HD Radio implementation. A configurable OFDM generator placed where hybrid IBOC sidebands would sit.

Mode-

Carriers-

Spacing-

Symbol rate-

Payload-

Sidebands-

SDR CLIENTS

Client	Address	Tuned	Rate	Data	Drop
No clients connected

STATISTICS

TRANSMITTER CONTROL

changes apply live; SAVE CONFIG writes config.toml

Station name Frequency (Hz) RF sample rate (Sa/s) FM deviation (Hz) RF gain RF bandwidth (Hz) Block size (samples)

The stereo encoder, pilot and pre-emphasis live in the MPX tab.

Stereo encoder Stereo width (L−R) Pilot level (19 kHz) Pre-emphasis Pre-emphasis (us) MPX sample rate (Hz) Audio volume Limiter FM deviation (Hz)

SCA SUBCARRIERS

subsidiary services above RDS

SCA 1 (67 kHz) Frequency (Hz) Injection Subcarrier deviation (Hz) Source Stream URL or file (its own service) Tone (Hz) Pre-emphasis (us)

SCA 2 (92 kHz) Frequency (Hz) Injection Subcarrier deviation (Hz) Source Stream URL or file (its own service) Tone (Hz) Pre-emphasis (us)

COMPOSITE BUDGET

peak -

Every subcarrier is derived from the same 19 kHz pilot accumulator, so 38 kHz and 57 kHz stay exactly locked to it. The percentages are of the configured peak deviation; a real station keeps the total at or below 100 % (plus the 10 % pilot).

Audio source Stream URL Audio file Backup audio Audio volume Limiter Audio sample rate Buffer (ms) Test tone (Hz) FFmpeg path Mic device Metadata mode Metadata URL (polled by the Python service) Metadata poll (s)

RDS enable Standard PS RadioText PI code PTY Injection (fraction) Use deviation instead RDS deviation (Hz) TP TA Music/Speech DI stereo Clock time (4A) AF enable AF list (MHz) RT A/B toggle Group sequence

Profile Letter case (station) PS case PS alignment RadioText case Plain ASCII PS template — fields separated by | RadioText template

Profiles come from the Python service on port 8000.

ON AIR NOW

changes apply as you type

PREVIEW

PS pages

RadioText-

Rendered-

Template variables and filters

PS mode Continuous scroll Chunk length Chunk delay (ms) Scroll speed Repeat count Separator Split on words PS letter case PS alignment Trim each page Scroll text (blank = station + RadioText; use | between fields)

Chunks change only at the end of a complete four-group PS transmission, so RDS group timing stays valid. PS letter case overrides the station-wide case for the eight-character display alone, so the PS can be ALL CAPS while RadioText keeps the programme's own case. Centring and right-alignment trim each page first.

Enable Threshold Ratio Attack (ms) Release (ms) Makeup (dB)

Broadcast compressor. Changes are applied to the FFmpeg input stage and restart only the audio decoder, not the transmitter frequency.

Enable Ceiling Attack (ms) Release (ms) Gain Reduction

Stereo-linked peak limiter protecting the FM composite path. The ceiling is linear full-scale, so -0.2 dB is approximately 0.977.

REAL NRSC-5 HD RADIO CONTROL

Live gr-nrsc5 MP1 exciter feeding the Virtual Radio IQ path. HD1/HD2/HD3 audio and ICY metadata are monitored independently.

Exciter

Checking...

Controls

KZPX-HD1

KZPX-HD2

KZPX-HD3

HD1 LIVE SOURCE

HD2 LIVE SOURCE

HD3 LIVE SOURCE

LIVE HD SIGNAL LEVEL

1.00× 0 = off · 1 = normal · 2 = 2×

HD2 uses YourRADIO 106.7. HD3 uses XL93.3. The manager controls the real NRSC-5 service, not the old HD simulation.

HD simulation REAL HD sideband level (0–2) Modulation Carriers per sideband FFT size Guard fraction Pilot spacing Sideband start (Hz) Sideband end (Hz) Constellation noise Data payload

SSB enable Mode Frequency offset (Hz) Bandwidth (Hz) Level Source Tone (Hz) FM deviation (Hz) CW text CW speed (WPM)

ISB carries real stereo on one suppressed-carrier signal: the left channel below the offset, the right channel above it. FM MPX composite feeds this stage with the station's own multiplex — pilot, L−R subcarrier and RDS included — so MPX + WFM is a complete second stereo station elsewhere in the spectrum, and MPX + USB/LSB is a composite link. Set the deviation to 75 000 Hz for a normal FM station.

Noise Multipath Multipath delay (us) Fading depth Fading rate (Hz)

Listen address RTL-TCP port Web port Max clients Follow client frequency Follow client sample rate Auto start API token (blank = no auth; required for LAN mode)

Port and address changes take effect after restarting the engine process.