Audio Surveillance Detection · Wireless Transmitters
Wireless Transmitter Detection
Detection of RF audio transmitters, GSM bugs, Wi-Fi surveillance devices, and all categories of wireless listening equipment.
Covert listening systems range from a single concealed microphone connected to a recorder in an adjacent space to a fully networked audio monitoring installation drawing power from building wiring. Wired audio devices present a particular detection challenge: because they have no RF transmission signature, standard RF detectors find nothing. These devices require non-linear junction detection (NLJD) — a specialized instrument that emits a microwave signal and detects the harmonic response of semiconductor components, identifying electronic devices regardless of whether they are powered, transmitting, or even assembled.
Empire Investigation LLC uses professional NLJD instruments as standard equipment in every sweep. This ensures that passive, hardwired, and non-transmitting devices receive the same detection thoroughness as actively transmitting equipment. No device is safe from a properly conducted professional sweep.
Wireless transmitters — the device most people think of when they think "bug" — are among the easiest for professionals to detect, because they actively broadcast an RF signal. Our spectrum analyzers, both broadband and swept-frequency, identify transmission signatures across the full RF spectrum including the sub-GHz bands commonly used by covert devices.
The Range of Wireless Surveillance Frequencies
Modern wireless surveillance devices operate across an enormous frequency spectrum. Traditional bugs transmit on FM, VHF, or UHF bands. More sophisticated devices use GSM cellular networks, allowing monitoring from anywhere in the world. Wi-Fi and Bluetooth-based devices transmit at 2.4 or 5 GHz. Each frequency range requires specific detection approaches — a single RF scanner is not sufficient.
Detection Challenges for Burst Transmission Devices
Advanced wireless transmitters may use burst transmission — compressing audio data and transmitting in brief, irregular intervals to avoid detection by continuous RF sweeps. Professional-grade spectrum analyzers with sufficient bandwidth and sensitivity are required to identify these evasion techniques.
What We Look For
- FM band transmitters (88–108 MHz)
- VHF and UHF audio transmitters
- GSM cellular bugs transmitting over mobile networks
- Wi-Fi 2.4 GHz and 5 GHz audio devices
- Bluetooth audio surveillance devices
- Burst transmission devices designed to evade standard detection
Our Sweep Process
Broadband RF Survey
Wide-band spectral analysis to identify all active transmissions in the environment.
Targeted Frequency Analysis
Narrow-band investigation of anomalous signals.
GSM and Cellular Scanning
Detection of cellular-network-based surveillance transmitters.
Wi-Fi Network Analysis
Identification of unauthorized devices on or near local wireless networks.
Source Location
Physical location of identified transmission sources.
Documentation
Technical report of all detected transmissions and device locations.
Frequently Asked Questions
Confidential Inquiry
Schedule a Confidential TSCM Sweep
If you suspect surveillance or want to verify your environment is secure, professional detection is the only way to know with certainty.
All inquiries handled with complete discretion.