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Troubleshooting

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foonerd edited this page Oct 6, 2026 · 15 revisions

Troubleshooting

Find the symptom, read what it means, try what is listed. If that does not help, the last section says what to include when asking in the community thread.

Contents

The dongle

The dongle is not found

  • Check that it is plugged in and shows up: over SSH, lsusb should list a line with RTL2838 or RTL2832 (USB id 0bda:2838 or 0bda:2832).
  • Try another USB port, and without a hub or extension cable to rule those out.
  • Only RTL2832U-based dongles are supported; see Dongles.

The dongle is in use by something else

The installer stops the Linux television driver from taking the dongle. If the dongle was plugged in while the plugin was being installed and a scan fails right afterwards, restart the player once.

Other software on the player that uses RTL-SDR dongles (an ADS-B receiver, a second radio program) holds the dongle while it runs. Stop it.

The dongle is not delivering a signal

The dongle is not delivering a signal. Unplug it, plug it in again, and play the station once more.

The dongle answered and tuned, but sent no samples. The plugin stops the station instead of leaving it silent.

  • Unplug the dongle and plug it in again, then play the station. Software cannot bring a dongle back from this state.
  • If it happens repeatedly: use a shorter or better USB cable, a different port, or a powered hub. Some cheap dongles do this from time to time.

Reception is much worse on the Raspberry Pi than on a PC

The player's own electronics radiate into the dongle and the antenna. Put the dongle on a USB extension cable away from the player, and the antenna further still. A good power supply for the Pi helps as well.

Scanning

A scan finds no stations

FM

  • Is the antenna connected, and long enough for FM? The short antenna of a cheap dongle picks up strong local stations at best; see Antennas.
  • Is the right FM region set? Outside Europe the band or raster differs; see Scanning.
  • Try a more sensitive FM Scan Sensitivity.
  • Test one strong local station directly with Diagnostics > Test FM Station. If that plays, the dongle and audio are fine and the question is reception.
  • A station that sends no stereo pilot (mono) is found by its carrier, when it is received fairly well and is not silent at the moment of the scan. If one is missing, scan again, or add it by hand (CSV import, Extend).

DAB

  • Is there DAB where you are? Not every country or region has it.
  • Use the Antenna Positioning Tools: the spectrum scan shows whether anything arrives in Band III, the channel validation whether an ensemble can be decoded.
  • DAB is vertically polarised in most countries: stand the antenna upright, near a window, away from electronics.

The FM scan misses a weak station I can receive

Choose Detailed for the scan (FM Radio Settings > FM Scan, or in the Station Manager's Rescan dialog). A fast scan listens where the band shows a signal; a weak station does not show there and is found only when it is listened to. Once a station is in the list, every later scan listens to it, fast or detailed, and keeps it on a little less than a new station must show.

A station is in the list and plays as noise

The scan lists what it can recognise as a station, which is less than what is pleasant to hear: a station at one or two dots of five has a pilot or a carrier the scan can find and a sound that is mostly hiss. A higher FM Scan Sensitivity setting (Moderate, Conservative) lists only the stations received well. A weak station right beside a strong one may improve at the 171 kHz FM Sample Rate; see Gain, Frequency and Loudness.

An entry can also sit one channel beside its station, or on a frequency that holds nothing. Press its frequency in the Station Manager: the tune dialog shows what each channel around it holds, plays any of them, and moves or deletes the entry. See Station Manager.

FM sounds brighter since version 1.4.6

It should. Until then every region was received with the 75 µs de-emphasis of the Americas; Europe, Asia and Australia broadcast for 50 µs and now get it, which is up to 3 dB more treble above 5 kHz. If you prefer it softer, use your player's tone control or equaliser.

FM sounds a little dull, or a little sharp

The de-emphasis may not match your country's broadcasts. Each FM region comes with one, 50 or 75 µs (East Asia, for South Korea and Taiwan, has 75 µs since version 1.4.9), and a country can differ from its region. Received with 75 µs, a 50 µs broadcast sounds dull; the other way round it sounds sharp. Set FM Radio Region > FM De-emphasis to the one that sounds right; the change applies from the next station played.

The FM scan lists stations slightly off frequency, or on the wrong raster

Set the FM region. Where stations sit on odd tenths with 200 kHz spacing (88.1, 88.3 ...), also set FM Scan Offset to 100 kHz.

A dongle that tunes a few kilohertz off (most low-cost ones) needs nothing set: a scan finds the error and the plugin corrects it; see Gain, Frequency and Loudness.

The FM scan lists a station that is not there

Next to a very strong transmitter a tuner can produce copies of that station on other frequencies. The scan checks for this and discards them; if one slips through at the most sensitive setting, delete it in the Station Manager (its tune dialog says what the channel holds), or scan at Balanced.

A dongle with an E4000 tuner (the Nooelec "XTR" models) makes a faint mirrored copy of every station. Before version 1.4.3 a scan could list the copy of a strong station as a station of its own; since then it checks for such copies. An entry left from an earlier scan that turns out not to be a station can be deleted in the Station Manager. See Dongles.

Faint FM stations come and go between scans

At Sensitive and Very Sensitive, stations at the edge of reception are found on one scan and not on the next. Stations you have played, named or marked are kept regardless.

A DAB scan misses an ensemble the antenna tools show as strong

The spectrum scan shows power, not whether the signal can be decoded. Reflections indoors can make a strong signal undecodable. Move the antenna, validate the channel again, and rescan.

Playing DAB

"... could not be received: no usable DAB signal on channel ..."

The decoder found no ensemble it could read on that channel within 30 seconds.

  • Reception: try again, and try other stations of the same ensemble. If none plays, improve the antenna position.
  • The station may have moved to another ensemble or left the air. Rescan DAB; stations that are gone can then be deleted.

The sound has gaps, burbles or stutters

The signal is at the edge of what can be decoded. DAB has no "a bit noisy": it plays cleanly or it breaks up.

  • Improve the antenna position; see Antennas.
  • Keep the dongle away from the player on a USB extension cable.
  • Leave Automatic DAB gain on. More gain does not help a weak signal that is already noisy.

A cheap dongle finds no DAB stations, or needed a PPM value

Leave PPM Correction at 0. The decoder measures the dongle's frequency error and follows it, up to about 140 ppm. A PPM value that was right for an earlier version of the plugin does no harm, but one that is wrong can keep stations from being found: set it back to 0.

A station takes several seconds to start

About six seconds is normal for DAB: the gain is measured, the decoder synchronises to the ensemble and finds the service before sound comes.

Playing FM

FM is noisy

  • Reception. FM gets noisy gradually as the signal weakens; a better antenna or position is the cure.
  • Leave Automatic FM gain on.

A station near a very strong one is distorted with automatic gain

Before version 1.4.5 the gain for a station was measured on a narrower part of the band than the receiver takes in. A very strong station up to 1.8 MHz above the one played could go unnoticed, and the station was then played with far too much gain: harsh, noisy sound that a lower manual gain cured. From 1.4.5 the gain is measured on the receiver's own part of the band. Each station is measured afresh the first time it is played after the update. If a station is still distorted, a dongle report shows the gain chosen for it.

No station name or text on an FM station

RDS needs clearly better reception than listening does. A station that plays with a little noise often delivers no RDS at all. Name the station yourself in the Station Manager; its logo is then found by the name.

FM is louder than it used to be

Since version 1.3.27 FM plays at the level of DAB and of music tracks. Before, it was 7 to 11 dB quieter. If you had turned the volume up for FM, turn it back.

The radio is louder than my other sources

Set FM Level or DAB Level in the plugin's settings to a lower value, then play a station again. See Gain, Frequency and Loudness.

Loud passages on FM sound distorted

Stop the station and look in the log for the line beginning Sound of FM. If it says "cut off at full scale", the station is louder than the level leaves room for: set FM Level to -3 dB or lower. If it says "stayed below full scale", or "touched full scale now and then, too seldom to hear", the distortion comes from reception: see FM is noisy above.

Names, logos and artwork

A station has no logo

  • Logos come from the broadcasters' own published lists. Not every broadcaster publishes one.
  • An FM station is found by its RDS code or by its name. Give an "FM 98.5" a name in the Station Manager.
  • Maintenance > Station Logos > Refresh Station Logos asks again.
  • Choose a logo yourself: press the station's logo frame in the Station Manager. See Station Logos.

No song is recognised from the sound

  • Recognition is off without a token, and when its switch is off: Station Manager > Maintenance > Song Recognition says which, and whether the service refused the token. The eye beside the field shows the token, to check it against your AudD dashboard.
  • By default the plugin asks only when the station's text names no song; where it does, the text is used. Set Ask to Always to ask for every song.
  • A song is shown only after two answers thirty seconds apart agree, so the first minute of a station shows none. Talk, advertisements and jingles are recognised as nothing, rightly.
  • The player's log says what was asked and answered: lines beginning "Song recogn".

No album artwork

See When no cover appears. Most often the station sends no usable text, or the confidence threshold is higher than the station's text reaches.

Wrong album artwork

A slogan or presenter's line was read as a song. Add the phrase to the Artwork Block List in the Station Manager, or raise the confidence threshold.

The picture flickers between cover and logo

Set Artwork Persistence to Keep until artist changes and leave Artwork Cool-off at 2 seconds or more.

The Station Manager

The page does not open

  • Use the player's IP address: http://<player address>:3456.
  • The buttons in the plugin's settings use the player's .local name, which some networks and devices do not resolve. Enter the IP address under Hostname/IP Override: the address only (192.168.1.50), not a URL.
  • In the Volumio app, open the address in a browser instead.
  • The plugin must be enabled.

Changes are not there after a reload

Changes to station rows are saved only when you press save (on the row, above the list, or in the bar at the bottom).

Updates, backups and lists

"Plugin rtlsdr_radio already exists" when installing a newer version

The message comes from Volumio, for an Install button used on a plugin that is already installed: the Install v... buttons in the plugin's Details dialog are for a first installation. Use Update on the plugin's entry instead. Nothing has to be uninstalled. See Updating the Plugin.

The Station Manager offers no update, or stays on Stable

Beta and Preview apply only with Plugins Test Mode switched on at http://<player address>/dev. The plugin store answers only players signed in to MyVolumio. See Updating the Plugin.

Stations disappeared after an FM rescan

An FM rescan removes stations it looked for and did not find, if you never touched them. Stations you named, marked, hid or played are kept. A rescan in better conditions brings the others back; a backup made before restores the old list.

The station list is empty after reinstalling

The plugin keeps a last good copy of the list with its backups and takes it over on a fresh installation. If the list is still empty, restore a backup in the Station Manager under Maintenance; see Backup and Restore.

No sound, although the station shows as playing and other sources play

The radio plays through Volumio's audio output like everything else. If a DSP plugin is in use, check its preset: an invalid filter setting silences every source that starts after it was loaded.

Looking at the log

The plugin writes what it does to the player's log, each line marked [RTL-SDR Radio]: the gain it measured, each slice of an FM scan, why a station was stopped, whether a station's sound stayed below full scale.

  • In the browser: open http://<player address>/dev and start Live Log, then repeat what fails.
  • Over SSH (switch SSH on at the same page):
journalctl -u volumio -f | grep "RTL-SDR Radio"

Asking for help

Ask in the community thread and include:

  • the plugin version (Station Manager > Maintenance > Plugin Update) and the Volumio version,
  • the player (for example Raspberry Pi 4) and the dongle (make and model),
  • what you did and what happened, with the message shown if there was one,
  • a log: at http://<player address>/dev, Send Log or bug report right after the problem gives a link to paste,
  • where reception or the dongle is in question, a dongle report (Station Manager > Maintenance): its summary pasted into the post, the file by a link.

FM/DAB Radio for Volumio · Source · Community thread · GPL-3.0

FM/DAB Radio

Using the radio

Managing it

Hardware

Help

Reference

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