intercept/docs/TROUBLESHOOTING.md

Troubleshooting

Solutions for common issues.

Python / Installation Issues

"ModuleNotFoundError: No module named 'flask'"

Install Python dependencies first:

pip install -r requirements.txt

# Or with python3 explicitly
python3 -m pip install -r requirements.txt

"TypeError: 'type' object is not subscriptable"

This error occurs on Python 3.7 or 3.8. INTERCEPT requires Python 3.9 or later.

# Check your Python version
python3 --version

# Ubuntu/Debian - install newer Python
sudo apt update
sudo apt install python3.11 python3.11-venv python3-pip

# Run with newer Python
python3.11 -m venv venv
source venv/bin/activate
pip install -r requirements.txt
sudo venv/bin/python intercept.py

"externally-managed-environment" error (Ubuntu 23.04+, Debian 12+)

Modern systems use PEP 668 to protect system Python. Use a virtual environment:

# Option 1: Virtual environment (recommended)
python3 -m venv venv
source venv/bin/activate
pip install -r requirements.txt
sudo venv/bin/python intercept.py

# Option 2: Use the setup script (auto-creates venv if needed)
./setup.sh

"pip: command not found"

# Ubuntu/Debian
sudo apt install python3-pip

# macOS
python3 -m ensurepip --upgrade

Permission denied during pip install

# Install to user directory
pip install --user -r requirements.txt

SDR Hardware Issues

No SDR devices found

1. Ensure your SDR device is plugged in
2. Check detection:
   • RTL-SDR: rtl_test
   • LimeSDR/HackRF: SoapySDRUtil --find
3. On Linux, add udev rules (see below)
4. Blacklist conflicting drivers:

   echo "blacklist dvb_usb_rtl28xxu" | sudo tee /etc/modprobe.d/blacklist-rtl.conf
   sudo modprobe -r dvb_usb_rtl28xxu
   

Linux udev rules for RTL-SDR

sudo bash -c 'cat > /etc/udev/rules.d/20-rtlsdr.rules << EOF
SUBSYSTEM=="usb", ATTRS{idVendor}=="0bda", ATTRS{idProduct}=="2838", MODE="0666"
SUBSYSTEM=="usb", ATTRS{idVendor}=="0bda", ATTRS{idProduct}=="2832", MODE="0666"
EOF'

sudo udevadm control --reload-rules
sudo udevadm trigger

Then unplug and replug your RTL-SDR.

Device busy error

1. Click "Kill All Processes" in the UI
2. Unplug and replug the SDR device
3. Check for other applications: lsof | grep rtl

LimeSDR/HackRF not detected

Ensure the correct SoapySDR module for your hardware is installed first

1. Verify SoapySDR is installed: SoapySDRUtil --info
2. Check driver is loaded: SoapySDRUtil --find
3. May need udev rules or run as root

Using HackRF/Airspy/LimeSDR with ADS-B

For non-RTL-SDR devices, ADS-B requires readsb compiled with SoapySDR support (standard dump1090 won't work).

Option 1: Run readsb separately and connect via Remote mode

1. Start readsb with your device:

   # HackRF
   readsb --device-type soapysdr --device driver=hackrf --net --quiet
   
   # Airspy
   readsb --device-type soapysdr --device driver=airspy --net --quiet
   
   # LimeSDR
   readsb --device-type soapysdr --device driver=lime --net --quiet
   

2. In Intercept's ADS-B dashboard:

   • Check the "Remote" checkbox
   • Enter Host: localhost and Port: 30003
   • Click START

3. Intercept will connect to readsb's SBS output on port 30003

Option 2: Install readsb with SoapySDR support

On Debian/Ubuntu:

# Install dependencies
sudo apt install build-essential debhelper librtlsdr-dev pkg-config \
    libncurses5-dev libbladerf-dev libhackrf-dev liblimesuite-dev libsoapysdr-dev

# Clone and build
git clone https://github.com/wiedehopf/readsb.git
cd readsb
dpkg-buildpackage -b --no-sign
sudo dpkg -i ../readsb_*.deb

Using HackRF/Airspy with Listening Post

The Listening Post requires rx_fm from SoapySDR utilities for non-RTL-SDR devices.

# Install SoapySDR utilities (includes rx_fm)
sudo apt install soapysdr-tools

# Verify rx_fm is available
which rx_fm

If rx_fm is installed, select your device from the SDR dropdown in the Listening Post - HackRF, Airspy, LimeSDR, and SDRPlay are all supported.

WiFi Issues

Monitor mode fails

1. Ensure running as root/sudo
2. Check adapter supports monitor mode: iw list | grep monitor
3. Kill interfering processes: airmon-ng check kill

Permission denied when scanning

Run INTERCEPT with sudo:

sudo python3 intercept.py
# Or with venv:
sudo venv/bin/python intercept.py

Interface not found after enabling monitor mode

Some adapters rename when entering monitor mode (e.g., wlan0 → wlan0mon). The interface should auto-select, but if not, manually select the monitor interface from the dropdown.

Bluetooth Issues

No Bluetooth adapter found

# Check if adapter is detected
hciconfig

# Ubuntu/Debian - install BlueZ
sudo apt install bluez bluetooth

Permission denied

Run with sudo or add your user to the bluetooth group:

sudo usermod -a -G bluetooth $USER

Decoding Issues

No messages appearing (Pager mode)

1. Verify frequency is correct for your area
2. Adjust gain (try 30-40 dB)
3. Check pager services are active in your area
4. Ensure antenna is connected

Cannot install dump1090 in Debian (ADS-B mode)

On newer Debian versions, dump1090 may not be in repositories. The recommended action is to build from source or use the setup.sh script which will do it for you.

No aircraft appearing (ADS-B mode)

1. Verify dump1090 is installed
2. Check antenna is connected (1090 MHz antenna recommended)
3. Ensure clear view of sky
4. Set correct observer location for range calculations or use gpsd

Satellite passes not calculating

1. Ensure skyfield is installed: apt install python3-skyfield
2. Check TLE data is valid and recent
3. Verify observer location is set correctly