SDRplay Service Fix for WaveCap-SDR

This skill helps diagnose and fix stuck SDRplay API service issues that prevent device enumeration.

When to Use This Skill

Use this skill when:

• SoapySDRUtil --find hangs or takes more than 5 seconds
• SDRplay RSP device not detected but USB device is present
• WaveCap-SDR shows "device timeout" or "failed to open" for SDRplay
• Capture using SDRplay device won't start
• Device enumeration gets stuck

Symptoms

1. Hanging enumeration: SoapySDRUtil --find never completes
2. Timeout errors: Device opens but times out during setup
3. Service stuck: sdrplay_apiService using excessive CPU or memory
4. Device shows in USB but not in SoapySDR: USB device present but not enumerated

Diagnosis

Step 1: Check if SDRplay USB Device is Connected

macOS:

system_profiler SPUSBDataType 2>/dev/null | grep -B5 -A10 "1df7\|SDRplay\|RSP"

Linux:

lsusb | grep -i "1df7\|sdrplay"

Windows (PowerShell):

Get-PnpDevice -Class USB | Where-Object { $_.FriendlyName -match "SDRplay" }

Step 2: Check SDRplay Service Status

macOS:

ps aux | grep -i sdrplay | grep -v grep

Expected output shows sdrplay_apiService running:

root  12345  0.0  0.1  123456  7890  ??  Ss   10:00AM  0:00.50 /Library/SDRplayAPI/3.15.1/bin/sdrplay_apiService

Linux:

systemctl status sdrplayService
# or
ps aux | grep -i sdrplay | grep -v grep

Windows (PowerShell):

Get-Service SDRplayService

Step 3: Test Device Enumeration with Timeout

macOS/Linux:

# Run SoapySDRUtil in background with manual timeout
SoapySDRUtil --find 2>&1 &
PID=$!
sleep 5
if ps -p $PID > /dev/null 2>&1; then
    echo "STUCK: Enumeration taking too long"
    kill $PID
else
    echo "OK: Enumeration completed"
fi

Fix: Restart SDRplay Service

macOS

Option 1: Using launchctl kickstart (preferred, returns new PID)

sudo /bin/launchctl kickstart -kp system/com.sdrplay.service

This kills the existing service and starts a fresh instance, returning the new PID.

Option 2: Using launchctl stop/start

sudo launchctl stop com.sdrplay.apiservice
sleep 2
sudo launchctl start com.sdrplay.apiservice

Option 3: Kill and auto-restart

sudo killall sdrplay_apiService

The service will auto-restart via launchd.

To allow passwordless restart, add to /etc/sudoers.d/sdrplay:

# Allow users to restart SDRplay service without password (kickstart is preferred)
%admin ALL=(ALL) NOPASSWD: /bin/launchctl kickstart -kp system/com.sdrplay.service
%admin ALL=(ALL) NOPASSWD: /bin/launchctl stop com.sdrplay.apiservice
%admin ALL=(ALL) NOPASSWD: /bin/launchctl start com.sdrplay.apiservice
%admin ALL=(ALL) NOPASSWD: /usr/bin/killall sdrplay_apiService

Create with:

sudo visudo -f /etc/sudoers.d/sdrplay

Linux

Option 1: Using systemctl (preferred)

sudo systemctl restart sdrplayService

Option 2: Kill and restart manually

sudo killall sdrplay_apiService
sleep 1
sudo /usr/local/bin/sdrplay_apiService &

To allow passwordless restart, add to /etc/sudoers.d/sdrplay:

# Allow users to restart SDRplay service without password
%plugdev ALL=(ALL) NOPASSWD: /bin/systemctl restart sdrplayService
%plugdev ALL=(ALL) NOPASSWD: /usr/bin/killall sdrplay_apiService

Create with:

sudo visudo -f /etc/sudoers.d/sdrplay

Windows

Option 1: Using PowerShell (as Administrator)

Restart-Service SDRplayService

Option 2: Using command prompt (as Administrator)

net stop SDRplayService
net start SDRplayService

Option 3: Using Services GUI

1. Open "Services" (services.msc)
2. Find "SDRplay API Service"
3. Right-click > Restart

Verify Fix

After restarting the service, verify the fix:

# Check new service PID (should be different)
ps aux | grep -i sdrplay | grep -v grep

# Test enumeration (should complete in <3 seconds)
SoapySDRUtil --find

Expected output includes SDRplay device:

Found device 1
  driver = sdrplay
  label = SDRplay Dev0 RSPdx-R2 240309F070
  serial = 240309F070

Alternative Fix: USB Reset

If service restart doesn't work, try physically unplugging and replugging the SDRplay USB device. Wait 3 seconds between unplug and replug.

macOS USB port location:

system_profiler SPUSBDataType | grep -B15 "1df7" | grep "Location ID"

Prevention

The SDRplay service can get stuck when:

• Application crashes while device is open
• Multiple applications try to access the device
• USB power issues cause device reset
• macOS sleep/wake interrupts the service

To minimize issues:

• Always properly close SDR applications before starting new ones
• Use a powered USB hub for SDR devices
• Avoid USB3 ports if experiencing issues (USB2 is more stable for SDR)

Integration with WaveCap-SDR

When WaveCap-SDR shows SDRplay device timeout:

1. Run this skill's diagnostic commands
2. Restart the SDRplay service
3. Refresh devices in WaveCap-SDR UI or restart the capture

Files in This Skill

• skill.md: This file - instructions for diagnosing and fixing SDRplay service issues