Spectral Bands: SDR Client

SPECTRAL // BANDS — Signal Intelligence for iOS

Your RTL-SDR. Your iPhone. No compromises.

Spectral Bands is a high-performance Software Defined Radio client built for operators who demand real-time signal visualization and clean audio demodulation on the go. Connect to any rtl_tcp or rtlsdr-next WebSDR server and put a full signal intelligence station in your pocket.

BUILT FOR THE BAND

Whether you're monitoring 2m repeaters, chasing HF SSB DX, scanning air traffic, or hunting numbers stations at 3am — SpectralBands handles it with a DSP pipeline engineered for accuracy, not approximation.

— WFM / NFM / AM / USB / LSB demodulation

— 1024-bin real-time waterfall with dynamic range calibration

— Calibrated spectrum analyzer, -100 to 0 dB

— Software AGC with noise gating

— Squelch control for NFM monitoring

— Adjustable IF filter bandwidth for SSB and AM

TWO PATHS, ONE CLIENT

Connect to an rtlsdr-next server for high-efficiency server-side DSP with lower mobile CPU load, or drop into full local processing mode against any standard rtl_tcp server — complete with multi-stage FIR decimation and Hilbert SSB.

The rtlsdr-next server software is open-source and can be hosted on any Linux or macOS machine with an RTL-SDR dongle. Search for 'rtlsdr-next' on GitHub for the official setup guide and high-performance daemon.

BUILT FOR THE FIELD

Background audio keeps your frequency monitored while you use other apps or lock your screen. A frequency bookmark registry lets you save and recall your favorite channels instantly. Reconnection logic handles mobile network handoffs without dropping your session.

THE INTERFACE

High-contrast OLED-optimized display designed for dark environments. If your shack looks like a 1980s cyberpunk film, you'll feel right at home.

Requires a networked RTL-SDR server (rtl_tcp or rtlsdr-next). iOS 18.6+, iPhone 12 or newer recommended.