How to Monitor FM, DAB and DVB-T2 Broadcast Signals

Broadcast Signal Monitoring

In the landscape of modern telecommunications, continuous monitoring of broadcast signals represents a fundamental element for ensuring service quality and operational continuity of transmission networks. The ability to detect, analyze and verify FM, DAB and DVB-T2 transmissions in real time constitutes an essential requirement for broadcasters, network operators and critical infrastructure managers.

The growing complexity of broadcast networks and the need to guarantee high quality standards require professional monitoring systems capable of operating continuously under any environmental conditions. In this context, choosing the right instrumentation becomes crucial for preventing service interruptions and optimizing network performance.

Broadcast Technologies: FM, DAB and DVB-T2

FM - Frequency Modulation (88-108 MHz)

Frequency modulation remains the most widespread audio broadcasting technology globally. Operating in the VHF band between 88 and 108 MHz, the FM system provides quality audio transmissions with extensive territorial coverage. FM technology uses frequency deviation proportional to the amplitude of the modulating signal, offering greater immunity to interference compared to amplitude modulation.

From a technical standpoint, each FM station occupies a bandwidth of approximately 200 kHz, with maximum deviation of ±75 kHz for the main audio signal. Monitoring FM transmissions requires analysis of parameters such as: received signal power (RSSI), frequency deviation, presence of the 19 kHz pilot carrier and modulation quality.

DAB - Digital Audio Broadcasting (174-240 MHz)

DAB represents the digital evolution of audio broadcasting, operating primarily in the VHF III band (174-240 MHz). This technology employs OFDM (Orthogonal Frequency Division Multiplexing) modulation with MPEG Audio Layer II encoding, enabling transmission of multiplexes containing multiple radio services in a single 1.536 MHz frequency block.

The DAB signal structure is based on 96 ms transmission frames, divided into OFDM symbols. Each DAB ensemble can carry up to 64 audio and data services, with variable bitrates from 8 to 384 kbps per service.

DVB-T2 - Digital Video Broadcasting Terrestrial 2 (470-790 MHz)

DVB-T2 constitutes the second-generation standard for digital terrestrial television, operating in the UHF band between 470 and 790 MHz. Compared to the previous DVB-T, it offers a transmission capacity increase of 30-50% thanks to the use of advanced technologies such as modulation up to 256-QAM, LDPC (Low Density Parity Check) code and constellation rotation.

The DVB-T2 system supports flexible configurations with bandwidths of 6, 7 or 8 MHz, various FFT modes (1K, 2K, 4K, 8K, 16K, 32K) and variable guard intervals. The signal structure is based on super-frames composed of T2-frames, enabling transmission of multiple PLPs (Physical Layer Pipes) with differentiated robustness parameters for HD, SD and data services.

Parameters in Broadcast Signal Monitoring

Professional monitoring of broadcast signals requires continuous analysis of essential radio frequency parameters. Received signal power, expressed in dBm or dBµV, constitutes the primary indicator of territorial coverage. The temporal variation of this parameter allows identification of propagation problems, interference or malfunctions in the transmitting system.

Analysis enables verification of bandwidth occupancy, identification of emissions and detection of co-channel or adjacent channel interference. The resolution bandwidth (RBW) of the measurement instrument must be appropriate for the type of signal being analyzed: typically 3-10 kHz for FM, 10-30 kHz for DAB and 30-100 kHz for DVB-T2.

Professional Monitoring Methodologies

Continuous 24/7 Monitoring

Implementation of a continuous monitoring system requires equipment designed to operate uninterrupted under extreme environmental conditions. IP67 certification guarantees complete protection against dust and temporary immersion, an essential element for outdoor installations on towers, tunnels or remote sites.

The monitoring architecture must provide historical data storage for trend analysis and retrospective troubleshooting. The capability to record parameters with adequate temporal granularity (typically sampling every 1-10 seconds) enables identification of intermittent problems and correlations with external events.

Alert and Notification Systems

An effective monitoring system must implement multi-level alert mechanisms based on configurable thresholds. Alarms can be generated for: carrier absence, power degradation below minimum thresholds, error threshold exceedance, anomalous variations in modulation parameters.

Notifications must be distributed through various channels: email for non-critical alarms, SNMP traps for integration with network management systems, relays for backup system activation, web dashboards for real-time network status visualization.

Practical Implementation

The TP-RFX System for Broadcast Monitoring

The TP-RFX represents a solution for outdoor monitoring of broadcast signals. Operating in the 15-2700 MHz band, it completely covers FM, DAB and DVB-T2 frequencies. IP67 certification and the 0-50°C operating range guarantee reliability in external installations.

PoE power supply simplifies installation by eliminating the need for local power supplies, while the N connector ensures compatibility with professional antenna systems. The -130 dBm to +10 dBm dynamic range, with protection up to +30 dBm, enables accurate measurements under various operating conditions.

The integrated web dashboard offers real-time spectrum visualization, multiple channel configuration for simultaneous FM, DAB and DVB-T2 monitoring, measurement history for temporal analysis and configurable notification system via email, SNMP and relays.

Professional monitoring of FM, DAB and DVB-T2 broadcast signals constitutes an indispensable element for guaranteeing service quality and continuity. Implementation of dedicated RF analysis systems, designed to operate under environmental conditions and equipped with advanced alert and historical functions, enables prevention of service disruptions and optimization of broadcast network performance.

The choice of adequate instrumentation, combined with monitoring methodologies, represents a strategic investment for broadcasters and network operators.