Also known as: DVB-T, DVB-T2, DTT
DVB-T (Digital Video Broadcasting — Terrestrial) and its successor DVB-T2 are the ETSI standards for over-the-air digital television used across Europe, much of Asia, Africa, and Australia.1 They carry compressed video and audio in an MPEG-2 transport stream over a coded orthogonal frequency-division multiplexing (COFDM) waveform, spreading the signal across thousands of QAM subcarriers so that a single 8 MHz channel survives the multipath of rooftop and indoor reception.
Overview
DVB-T packs digital television into the 6, 7, or 8 MHz raster once used by a single analog channel. Rather than one high-rate carrier, it distributes the payload over 1,705 subcarriers (“2K mode”) or 6,817 (“8K mode”); DVB-T2 extends this to 32K. Each subcarrier is modulated with QPSK, 16-QAM, or 64-QAM (T2 adds 256-QAM). A guard interval — a cyclic repetition prepended to every OFDM symbol — absorbs echoes from reflections and from other transmitters in a single-frequency network, which is what lets terrestrial TV work with a simple indoor antenna.
Technical characteristics
| Property | Value |
|---|---|
| Waveform | COFDM (OFDM + FEC) |
| Subcarriers | 2K / 8K (DVB-T); 1K–32K (DVB-T2) |
| Subcarrier modulation | QPSK, 16-QAM, 64-QAM; +256-QAM in T2 |
| Inner code | Convolutional (T), LDPC (T2) |
| Outer code | Reed–Solomon (T); BCH (T2) |
| Guard interval | 1/4, 1/8, 1/16, 1/32 of symbol |
| Payload | MPEG-2 transport stream (MPEG-2, H.264, HEVC video) |
| Peak bitrate | ≈ 31 Mbit/s (T), ≈ 50 Mbit/s (T2, 8 MHz) |
History
The DVB Project published DVB-T as ETSI EN 300 744 in 1997, and the first services launched in the UK in 1998.2 It pairs concatenated forward error correction — an outer Reed–Solomon code over an inner convolutional code — with COFDM. DVB-T2 (EN 302 755, 2009) replaced that stack with a far stronger BCH-plus-LDPC scheme borrowed from the DVB-S2 satellite standard, raising capacity by roughly 30–50% and enabling terrestrial HD and UHD.
Deployment
DVB-T and DVB-T2 are the dominant terrestrial systems outside the Americas, Japan, and China. Most European countries have migrated, or are migrating, to DVB-T2 with HEVC to reclaim spectrum for mobile broadband. Transmitters are often arranged in single-frequency networks, where many sites share one channel and the guard interval turns overlapping signals into constructive multipath rather than interference.
Decoding it with GopherTrunk
GopherTrunk is a land-mobile trunking scanner and does not demodulate DVB-T; MPEG transport-stream video is outside its scope. The RF signal is, however, perfectly receivable with the same software-defined radio hardware: an 8 MHz DVB-T channel exceeds the ~2.4 MHz bandwidth of an RTL-SDR — indeed the RTL2832U demodulator was designed for DVB-T before hobbyists repurposed it — but a wider receiver such as an Airspy or HackRF can capture the full channel for analysis in dedicated tools. Related terrestrial and satellite variants are covered under DVB-C and DVB-S.
Sources
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DVB-T — Wikipedia, for the terrestrial DVB standard, its COFDM waveform, subcarrier modes, and QAM constellations. ↩
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EN 300 744 (DVB-T framing and modulation) — ETSI, the primary standard defining DVB-T channel coding and OFDM modulation. ↩