OpenWebRX RTL-SDR Configuration Files

Ready-to-use settings.json configurations for OpenWebRX, built and tested for the RTL-SDR Blog V4, RTL-SDR Blog V3, and Nooelec NESDR V5 receivers. Each file provides full continuous coverage from 500 kHz to 1.766 GHz, segmented into logical device groups for clean navigation inside OpenWebRX.

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Changelog

v2.0 — Bug Fix Release (April 2026)

This release resolves several critical issues that caused the OpenWebRX error:

SDR device "[name]" has failed, selecting new device

All fixes were applied identically to both settings_v3_segmented.json and settings_v4_segmented.json unless noted.

Fix 1 — Section divider profiles missing rf_gain (27 profiles per file)

Section header profiles (keys prefixed with _, e.g. _frs, _gmrs, _vhf) are used as visual separators in the OpenWebRX profile list. These profiles were missing the rf_gain field entirely. When OpenWebRX selected one of these as the active profile — either on initial load or when switching bands — the RTL-SDR driver rejected the incomplete configuration and triggered the device failure error.

Fix: Added rf_gain to all 27 divider profiles in each file, derived from the median gain of the real profiles within the same device group.

Affected device groups: HF Broadcast, Amateur VHF/UHF, Aviation, Public Safety, Pagers, FRS/GMRS, ISM/Satellite, VHF Low/TV.

Fix 2 — FRS/GMRS and Amateur HF: sample rates below RTL-SDR hardware minimum (27 profiles per file)

The RTL-SDR driver (librtlsdr) has a hard minimum sample rate of ~225,001 Hz. Any value below this causes the driver to fail immediately, producing the device failure error.

Two groups of profiles were affected:

FRS/GMRS individual channel profiles (frs_01–frs_14, gmrs_15–gmrs_22) — set to samp_rate: 25000 (25 kHz) in an attempt to show a single channel at a time. While logical in intent, this value is far below the hardware floor.

Amateur HF narrow-band profiles — five profiles with sample rates that were too low for the driver to accept:

Profile	Band	Old Rate	Fixed Rate
ham_160	160m	200,000 Hz	250,000 Hz
ham_60	60m	75,000 Hz	250,000 Hz
ham_30	30m	50,000 Hz	250,000 Hz
ham_17	17m	100,000 Hz	250,000 Hz
ham_12	12m	100,000 Hz	250,000 Hz

Fix: All affected profiles raised to samp_rate: 250,000 Hz — the smallest valid rate. The 250 kHz window still provides a tight, focused view of each channel or band segment.

Fix 3 — Aviation Military Airband: sample rate data entry error (7 profiles per file)

Profiles mil_001 through mil_007 (Military Airband 225–400 MHz) had samp_rate: 25000000 (25 MHz). The RTL-SDR maximum is 3.2 MHz. This was a transcription error — a missing zero.

Fix: Corrected to samp_rate: 2500000 (2.5 MHz) across all seven profiles.

Fix 4 — ISM/Satellite: two profiles with center frequencies beyond hardware range

Profile	Name	Old center_freq	Fix
dect	DECT Cordless	1,890,000,000 Hz (1890 MHz)	Capped to 1,766,000,000 Hz; name updated to indicate hardware limitation
lb_1734_014	L-Band 1765–1766 MHz	1,766,400,000 Hz	Nudged to 1,765,000,000 Hz

The RTL-SDR V3 and V4 have a hardware ceiling of approximately 1,766 MHz. DECT at 1880 MHz is outside the range of any RTL-SDR device; a HackRF or Airspy R2 would be required to receive it.

Fix 5 — V4 only: HF and lower Amateur HF profiles missing direct_sampling

The V4 settings file was missing direct_sampling: "2" on 26 HF profiles (all VLF/LW/AM/SW broadcast and Amateur HF profiles below 24 MHz). Without this flag, the V4 driver does not engage Q-branch direct sampling mode for these frequencies, resulting in noise instead of signal.

Note: The V3 file had these set correctly already. This was a V4-specific omission.

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Files

File	Device	HF Method
settings_v4_segmented.json	RTL-SDR Blog V4 (R828D)	Built-in upconverter — no extra config needed
settings_v3_segmented.json	RTL-SDR Blog V3 (R820T2), Nooelec NESDR V5	direct_sampling: "2" on all HF profiles

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Device Groups

Both files share the same 9 logical device groups. Each appears as a separate selectable device in OpenWebRX while pointing to the same physical hardware (device_index: 0).

Group	Frequency Range	What's Inside
HF Broadcast	14 kHz – 108 MHz	VLF Nav, LW, NDB, AM broadcast, all SW bands, FM tiled
Amateur HF	1.8 – 54 MHz	160m through 6m, CB, inter-band scan fills
Amateur VHF/UHF	144 – 450 MHz	2m, APRS, 1.25m, 70cm, FT8 spot frequencies
Aviation	108 – 1090 MHz	VOR/ILS, Airband Comm, ACARS, Military, ADS-B, Mode S
VHF Low / TV	29.7 – 88 MHz	VHF utility/land mobile, VHF TV Ch2–6
Public Safety	150 – 960 MHz	VHF EMS/Fire, Marine VHF, UHF Fed, Land Mobile, 700/800 MHz trunked
Pagers	152 MHz + 929–932 MHz	POCSAG (VHF) and FLEX (UHF) — page mode enabled
FRS / GMRS	462 – 468 MHz	All 14 FRS channels, 8 GMRS simplex, repeater in/out pairs, panoramic overview
ISM / Satellite	433 MHz – 1.766 GHz	ISM 433/915, Inmarsat, GPS L1, GLONASS, Iridium, NOAA HRPT, DECT

Total: 788 profiles. Zero gaps between 500 kHz and 1.766 GHz.

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Key Settings

• Bandwidth: 2.4 MHz per profile (stable maximum for both V3 and V4)
• Tuning step: 10 Hz for SSB modes, 100 Hz for all others, 1 Hz for APRS/ADS-B
• Squelch: Pre-set on Public Safety, Marine, FRS/GMRS, and Pager profiles
• RF Gain: 35 dB default; 40 dB on weak-signal profiles (VLF, NOAA, pagers); 49 dB at the V4 hardware upper edge

V3 Specific

All profiles with a center_freq below 28.8 MHz have direct_sampling: "2" set automatically. This enables Q-branch sampling on the R820T2, which is required for HF reception on the V3 since it has no built-in upconverter. RF gain on those profiles is also bumped +5 dB to compensate. No additional driver configuration is needed beyond what the V3 already requires.

Nooelec NESDR V5 Compatibility

The settings_v3_segmented.json file has been confirmed working on the Nooelec NESDR V5. Use it the same way as the V3 file — the direct sampling configuration and gain settings are compatible with the NESDR V5's R820T2 tuner.

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Installation

Using GitHub Desktop

1. Clone or download this repository to your machine
2. Copy the appropriate file to your OpenWebRX config directory:
   • Docker: /opt/openwebrx/ or the volume mapped to your container's config path
   • Native install: /etc/openwebrx/
3. Rename the file to settings.json (replacing any existing file)
4. Restart OpenWebRX

# Example for native install
cp settings_v4_segmented.json /etc/openwebrx/settings.json
sudo systemctl restart openwebrx

Backup first. Replace your existing settings.json only after saving a copy.

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RTL-SDR Hardware Notes

V4 (R828D)

• Built-in upconverter handles HF natively — no direct_sampling needed
• Triplexed SMA input (HF / VHF / UHF) for better isolation
• Built-in AM/FM/DAB notch filters
• Requires RTL-SDR V4 drivers (librtlsdr 0.6.0+)

V3 (R820T2)

• No upconverter — HF via direct sampling Q-branch
• Standard RTL-SDR drivers work fine
• Slightly lower HF sensitivity than the V4 — consider an external LNA for weak HF signals

Nooelec NESDR V5

• Compatible with settings_v3_segmented.json
• Uses the same R820T2 tuner family as the RTL-SDR Blog V3
• Standard RTL-SDR drivers — no special configuration required

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Customization

Each profile is a standard OpenWebRX profile object. Common adjustments:

• ppm — set your calibrated PPM offset (default 0)
• rf_gain — adjust per your antenna and local noise floor
• initial_squelch_level — raise if your area has a high noise floor
• device_index — change if you have multiple RTL-SDR devices connected

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Requirements

• OpenWebRX (version supporting settings.json v8)
• RTL-SDR Blog V4, RTL-SDR Blog V3, or Nooelec NESDR V5 receiver
• Appropriate drivers installed for your device