Band I
Band I is a sub-band within the very high frequency (VHF) portion of the radio spectrum, designated for television broadcasting and spanning 47 to 68 MHz in the European Broadcasting Area.[1] This allocation, established under international standards by the International Telecommunication Union (ITU) and detailed by the European Broadcasting Union (EBU), primarily supported analog television transmissions on three channels (2, 3, and 4), each typically occupying 7 MHz of bandwidth in most European countries.[2][3] Historically, Band I played a foundational role in early postwar television rollout across Europe, enabling the transmission of monochrome and later color signals using standards such as System I (625 lines, 25 frames per second) in countries like the United Kingdom and Ireland.[2] Channel 2's vision carrier frequency is at 48.25 MHz, Channel 3 at 55.25 MHz, and Channel 4 at 62.25 MHz, with sound carriers offset by 5.5 MHz higher to accommodate positive modulation schemes.[3] In contrast, allocations in the Americas differ, with Band I-equivalent frequencies from 54 to 72 MHz used for low-VHF TV channels 2 through 4 under NTSC standards, though the "Band I" nomenclature is predominantly European.[2] With the widespread adoption of digital terrestrial television (DTT) in the 2000s and 2010s, analog usage in Band I has largely ceased in Western Europe, leading to spectrum repurposing for services like digital radio (e.g., DRM), amateur radio, or mobile applications in some nations.[2] However, remnants of analog broadcasting persist in select Eastern European countries as of the mid-2020s, and the band remains allocated to broadcasting on a primary basis under the ITU Radio Regulations to support potential future digital services.[1] Its propagation characteristics, favoring line-of-sight transmission with moderate range, made it suitable for urban and regional TV coverage before higher bands like UHF became dominant.[2]Definition and Characteristics
Frequency Allocations
Band I, defined as the lower portion of the VHF spectrum, encompasses frequency ranges allocated primarily for terrestrial television broadcasting, with variations across ITU regions to accommodate regional regulatory frameworks and technical requirements. These allocations are governed by the ITU Radio Regulations, particularly Article 5, which specifies primary service designations for broadcasting in the 47-88 MHz range.[4] In ITU Region 1, covering Europe, Africa, the Middle East, and parts of Asia, Band I is allocated from 47 to 68 MHz for analogue television broadcasting on a primary basis. This range supports three channels (E2 to E4) under the Geneva 2006 Agreement (GE06), each with a 7 MHz bandwidth to facilitate sound and vision transmission. The vision carrier frequencies are standardized at 48.25 MHz for Channel E2 (47-54 MHz), 55.25 MHz for Channel E3 (54-61 MHz), and 62.25 MHz for Channel E4 (61-68 MHz), ensuring compatibility across the European Broadcasting Area. Guard bands of 1 MHz separate channels to minimize adjacent-channel interference.[5] ITU Region 2, encompassing the Americas, allocates Band I from 54 to 88 MHz (with a gap from 72 to 76 MHz reserved for other services, such as radio astronomy), supporting low-band VHF television channels 2 through 6 on a primary basis. Each channel utilizes a 6 MHz bandwidth, reflecting the narrower standards of systems like NTSC. Vision carrier frequencies are set at 55.25 MHz for Channel 2 (54-60 MHz), 61.25 MHz for Channel 3 (60-66 MHz), 67.25 MHz for Channel 4 (66-72 MHz), 77.25 MHz for Channel 5 (76-82 MHz), and 83.25 MHz for Channel 6 (82-88 MHz). To mitigate co-channel interference, particularly in border areas, offsets of up to 1.25 MHz may be applied to carrier frequencies, as permitted by national regulators like the FCC. Guard bands are integrated into the 6 MHz channel spacing, with no additional explicit separations noted beyond standard inter-channel gaps.[6] In ITU Region 3, spanning Asia-Pacific, allocations for Band I are more variable, often aligning with 47-68 MHz but with national deviations. The core range is 47-68 MHz for television broadcasting, using 6 or 7 MHz channel bandwidths depending on the country. For instance, Australia employs low VHF channels overlapping approximately 44-70 MHz (channels 0-2) for analogue television. Vision carrier frequencies follow regional standards, such as 57.25 MHz and higher, with guard bands varying by implementation to avoid interference from mobile services.[7] Following the global transition to digital terrestrial television in the 2009-2020s, Band I allocations have been reduced in many countries, with portions auctioned for mobile broadband services due to the spectrum efficiency of digital formats. In Region 1, analogue switch-off under GE06 has led to repurposing of upper Band I frequencies for digital audio or mobile uses in select nations; as of 2025, much of 47-68 MHz is allocated to land mobile services in many European countries.[5] Similarly, in Region 2, the U.S. digital transition (completed 2009) prompted some low-VHF stations to relocate, freeing spectrum segments for secondary allocations, though low VHF remains in use for digital TV with reduced station count as of 2025.[6] Region 3 countries, including Australia, have similarly reallocated parts of Band I post-switchover, prioritizing mobile services while retaining limited broadcasting. These changes reflect ITU guidelines on spectrum refarming without altering primary boundaries in the Radio Regulations.[8][6]| ITU Region | Frequency Range (MHz) | Channel Bandwidth (MHz) | Example Vision Carriers (MHz) | Key Notes |
|---|---|---|---|---|
| Region 1 | 47-68 | 7 | 48.25, 55.25, 62.25 | Channels E2-E4; 1 MHz guard bands; GE06 coordination.[5] |
| Region 2 | 54-88 (gap 72-76) | 6 | 55.25, 61.25, 67.25, 77.25, 83.25 | Channels 2-6; 1.25 MHz offsets possible; FCC standards.[6] |
| Region 3 | Variable (e.g., 47-68) | 6-7 | Varies (e.g., 57.25+) | National variations; partial overlaps in countries like Australia. |