WebSDR Integration

Remote receiver listening, recording, playback, and clip export

Connect to KiwiSDRA software-defined radio receiver that can be accessed remotely via web browser or WebSocket connection. public receivers worldwide to monitor your transmissions from a remote location. Record audio during logging sessions and play back recordings with QSO-synced navigation.

Overview

The WebSDR integration allows you to:

  • Listen remotely to your transmission by connecting to public KiwiSDRA software-defined radio receiver that can be accessed remotely via web browser or WebSocket connection. receivers
  • Record audio during POTAParks on the Air - a program encouraging portable operation from parks and public lands. activations and logging sessions
  • Play back recordings with QSO markers and waveform visualization
  • Share clips of individual QSOs or time ranges with embedded metadata
  • Integrate with CW transcription for decoded Morse overlay

This is invaluable for:

  • Checking your signal quality from a remote location
  • Documenting activations with audio evidence
  • Reviewing your operating technique
  • Sharing memorable QSOs

Finding Receivers

Carrier Wave queries the public KiwiSDRA software-defined radio receiver that can be accessed remotely via web browser or WebSocket connection. directory to help you find receivers near your operating location.

Receiver Browser

The receiver browser displays:

  • Distance from your grid squareA location identifier using the Maidenhead Locator System (e.g., FN31 for the Boston area). (sorted by proximity)
  • Live SNR and user count
  • Antenna details with visual badges:
    • Antenna type (e.g., “Longwire”, “Loop”, “Vertical”)
    • Band coverage (e.g., “160m-10m”)
    • Directionality (e.g., “Omnidirectional”, “E-W”)

Band Match Highlighting

During POTAParks on the Air - a program encouraging portable operation from parks and public lands. activations, receivers that support your current band display a “Good for 40m” badge (or whichever band you’re operating). This helps you quickly find receivers optimized for your frequency.

Receiver Selection Strategies

Carrier Wave supports multiple receiver selection strategies:

  • Near spotter - Select a receiver close to an RBN skimmer that heard you (confirms the propagation path)
  • Near activator - Select a receiver close to a station you’re trying to work (checks if you can be heard there)
  • Near QTH - Select a receiver close to your home location (useful for monitoring your own signal)
  • Auto-select - Carrier Wave picks the best available receiver based on your current band, available capacity, and signal quality

Receivers are sorted by distance from your grid squareA location identifier using the Maidenhead Locator System (e.g., FN31 for the Boston area). . The closest receivers appear first, making it easy to find strong local reception.

Cellular Warning

When connected via cellular data (not Wi-Fi), Carrier Wave displays a warning banner:

  • Data usage estimate based on audio quality and recording duration
  • Wi-Fi recommended for extended recording sessions
  • Continue anyway option if you accept the data usage

Favorites

Mark frequently-used receivers as favorites for quick access.

Adding Favorites

Tap any receiver card to expand a detail sheet with full information. Tap the star icon to favorite. Favorites appear at the top of the receiver list.

iCloud Sync

Favorites sync across all your devices via iCloud. Add a favorite on your iPhone, and it appears on your iPad.

Favorites Management

Navigate to Settings > WebSDR Favorites to:

  • Search favorites by name or location
  • Sort by proximity to your current grid
  • Remove favorites

Manual Receiver Entry

To add a private or unlisted KiwiSDRA software-defined radio receiver that can be accessed remotely via web browser or WebSocket connection. :

  1. Go to Settings > WebSDR
  2. Enable Advanced Mode
  3. Tap Add Manual Receiver
  4. Enter the receiver’s host:port (e.g., sdr.example.com:8073)

Carrier Wave validates the connection before saving. Manual receivers appear alongside public ones and can be favorited.

Connecting

Starting a Connection

In the logger, enter the WEBSDR command to:

  • Open the receiver picker (first time)
  • Reconnect to the last-used receiver (subsequent times)

Alternatively, tap any receiver card in the picker to connect immediately.

Connection Process

Carrier Wave establishes a WebSocket connection to the receiver and:

  1. Authenticates with the server
  2. Tunes to your session frequency and mode
  3. Starts receiving audio packets
  4. Begins recording (if auto-record is enabled)

Resilient Reconnects

If the connection drops (network interruption, receiver reboot), Carrier Wave:

  • Retries up to 5 times with exponential backoff
  • Preserves your recording file and duration timer
  • Resumes audio from where it left off
  • Fills silence gaps in the recording to maintain accurate timeline

Receiver Quality Monitoring and Fallback

Carrier Wave continuously monitors the connected receiver’s quality:

  • Audio level tracking - Detects if the receiver goes silent or produces only noise
  • Latency monitoring - Tracks round-trip time to the receiver
  • User count - Monitors receiver load
  • Automatic fallback - If quality degrades below a threshold for more than 30 seconds, Carrier Wave can automatically switch to the next-best available receiver (if auto-select is enabled)
  • Manual override - A quality indicator in the WebSDR panel lets you see current receiver health and switch manually

Redirect Handling

Some KiwiSDRA software-defined radio receiver that can be accessed remotely via web browser or WebSocket connection. servers redirect to alternate addresses. Carrier Wave follows up to 3 redirect hops and caches the effective host/port for faster reconnects.

Tuning

When connected, the receiver automatically:

  • Tunes to your session frequency
  • Switches to your session mode (e.g., SSBSingle Sideband - a voice mode commonly used on HF bands. , CWContinuous Wave - another term for Morse code communication. )
  • Applies filter bandwidth appropriate for the mode:
    • CWContinuous Wave - another term for Morse code communication. : 300-800 Hz
    • SSBSingle Sideband - a voice mode commonly used on HF bands. : 2.4 kHz
    • AM : 6 kHz

CW Pitch Offset

For CWContinuous Wave - another term for Morse code communication. , Carrier Wave applies a pitch offset so the signal lands in the audio passband (typically 500-700 Hz). This ensures you hear the tone clearly.

QSY Detection and Auto-Retune

When you change your operating frequency in the Logger (via frequency entry, the BAND command, or BLE radio sync), the WebSDR receiver automatically retunes:

  • Immediate retune when you enter a new frequency
  • Mode change detection triggers appropriate filter bandwidth adjustment
  • Band change detection may trigger receiver switch if the current receiver doesn’t cover the new band
  • Seamless - Recording continues uninterrupted during retune

Frequency Changes

Change your session frequency or mode in the logger, and the receiver re-tunes automatically. No need to disconnect and reconnect.

Live Playback

Audio from the receiver plays through your device’s speakers or headphones.

Jitter Buffering

Carrier Wave uses a ring buffer (5-second capacity) to smooth out network jitter. Audio pre-buffers for 1 second before playback begins, preventing stutter.

Controls

  • Mute button to silence audio without disconnecting
  • Buffer health indicator shows how full the ring buffer is (green = healthy, yellow = low, red = underrun)

Background Audio

Audio continues playing when you background the app or lock your device. The connection remains active, and recording continues.

Instant Replay

During a live WebSDR session, tap the Replay button in the WebSDR panel to instantly re-hear the last 15 seconds of captured audio. This is useful when you miss part of a callsign or exchange.

Triggering Replay

You can trigger a replay in three ways:

  • Replay button in the WebSDR panel toolbar
  • Logger commands: Type REPLAY, AGN, or HUH in the callsign entry field

The replay plays back the buffered audio without interrupting the live connection. New audio continues to be captured during playback.

WebSDR Panel

The WebSDR panel (visible while connected) displays:

  • Connection status (connected, reconnecting, disconnected)
  • Frequency and mode
  • Filter bandwidth
  • Level meter showing received audio strength
  • Recording duration (if recording is active)
  • Quality indicator showing receiver health
  • Browser link to open the receiver’s web interface in Safari

Recording

Carrier Wave can record audio from the receiver to document your session.

Auto-Record

Enable Auto-record during sessions in Settings > WebSDR. When enabled, recording starts automatically when you connect to a receiver during an active logging session.

Manual Recording

Tap the Record button in the WebSDR panel to start/stop recording manually. You can record outside of sessions (e.g., listening to a contest).

Recording File

Audio is compressed and saved to a file on your device. Recordings include:

  • Timestamp (start time)
  • Session ID (if part of a session)
  • Frequency and mode changes with timestamps
  • QSO markers synced to timestamps

Gap Filling

If the connection drops during recording:

  • Carrier Wave fills the gap with silence to maintain an accurate timeline
  • The recording duration continues incrementing
  • When reconnected, audio resumes at the correct position

Recording Continuity

Recording persists across:

  • Pause/resume (tap the pause button)
  • Disconnect/reconnect (network interruption)
  • Frequency/mode changes

Dormant State

If you disconnect intentionally (e.g., moving to a new location), the recording enters a dormant state for up to 30 minutes. Reconnect within that window, and recording continues seamlessly.

Recording Badge

While recording is active, a persistent badge appears in the logger header. Tap the badge to view recording duration and controls. The badge remains visible even when the WebSDR panel is collapsed.

Recording Playback

Tap a session’s recording in the session detail view or compact player card to open the full-screen playback interface.

Waveform Visualization

The waveform shows:

  • Amplitude envelope (visual representation of audio level)
  • QSO markers (vertical lines at each QSO timestamp)
  • Active QSO highlight (the QSO corresponding to the current playback position)

Playback Controls

  • Play/Pause button
  • Drag-to-seek scrubber to jump to any position
  • Speed control (0.5x, 0.75x, 1x, 1.25x, 1.5x, 2x)

Speed Control

Adjust playback speed for review:

  • 0.5x - Half speed for detailed CW analysis
  • 0.75x - Slightly slower for catching details
  • 1x - Normal speed
  • 1.25x-2x - Faster for scanning through long recordings

Speed changes are smooth (no audio artifacts) and maintain correct pitch.

QSO-Synced Navigation

  • Tap a QSO in the list to seek to that QSO’s timestamp
  • Scrub the waveform to highlight the active QSO
  • Auto-scroll to keep the active QSO visible in the list

Transcript Sync with Playback

When CW transcription data is available for the recording, the transcript scrolls in sync with audio playback:

  • Highlighted text shows the portion of the transcript corresponding to the current playback position
  • Tap transcript text to seek to that point in the recording
  • Conversation view updates to show the active exchange

Compact Player

Recordings appear as inline cards in:

  • POTAParks on the Air - a program encouraging portable operation from parks and public lands. activation detail view
  • Sessions list

The card displays:

  • Mini waveform (simplified amplitude envelope)
  • Recording duration
  • Tap to expand to full-screen player

Clip Export with Metadata

Export a time range from a recording as a standalone audio file with embedded metadata.

Creating a Clip

  1. Open the recording playback interface
  2. Tap the Share button
  3. Adjust the range handles to select the desired time window (default: active QSO start/end)
  4. Tap Export Clip

M4A Export

The clip is exported as an M4A file (compressed audio) with metadata tags:

  • Title - Callsign and QSO date
  • Artist - Your callsign
  • Album - Session name
  • Comment - Frequency, mode, park reference
  • Artwork - Session thumbnail

Sharing

Share via the iOS share sheet:

  • AirDrop
  • Messages
  • Email
  • Save to Files

Recordings Management

View and manage all recordings in Settings > WebSDR Recordings.

Recording List

The list shows:

  • Recording thumbnail (mini waveform)
  • Date and duration
  • Session name (if part of a session)

Actions

  • Share a recording (full file or clip)
  • Delete a recording to free space

Deleted recordings cannot be recovered.

See Also