Australasian television frequencies
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[edit] Differences in Terrestrial TV frequencies
[edit] What led to the differences
What are the important underlining circumstances that led to the different allocations?
- Universally the VHF low band channels of (0), 1, 2, and 3 were allocated on an ad-hoc basis in Australia and NZ without any trans-Tasman coordination.
- Australia decided against adopting the 405 line system, and indirectly forbade its experimental transmission in the VHF band until the 625 line system could be launched.
- Only after AU-VHF-6 was allocated did NZ adopt the same VHF high band allocations as Australia.
- There never have been any ongoing attempts at coordination of TV allocations in Australasia until the 1990s.
- Australia adopted 7 MHz channel spacing (PAL B) on UHF as the 8 MHz allocation associated with later versions of PAL and SECAM had not emerged.
- New Zealand considered using 405 lines for television, but adopted 7 MHz 625 lines on both the VHF low band and high band. New Zealand's initial choice of frequencies in the VHF range (CH: 1, 2, 3) was done on an ad-hoc basis. The ad-hoc allocations in the VHF low band immedeatly led to substantial discrepancies with Australia's VHF TV service allocation for channels allocated before AU-VHF-6.
- The NZ 405 line allocation principal only affects NZ VHF CH1, CH2 and CH3.
- Fiji, Papua New Guinea and New Zealand all adopted 8 MHz channel spacing (PAL G) on UHF more or less in unison due to their later adoption of PAL.
[edit] The important differences
Australia and New Zealand evolved different TV frequency allocations for historically different reasons for this occurrence.
- Both Australia and New Zealand use 7 MHz channel spacing (PAL B) on VHF, but the frequencies and channel numbers differ even more substantially now because of Australia revising its VHF TV band usage.
- Australia adopted Zweiton stereo, and NZ adopted NICAM stereo.
- For analog PAL service the only difference is the placement of the NICAM carrier vs the Zweiton carrier, for broadcasters using NICAM.
[edit] Important similarities
- Except for a channel offset factor for Australia: Australia, NZ, Fiji and PNG have the same UHF band allocation for TV broadcasting.
[edit] Obsolete channels
[edit] Australia
Channel obsolescence related to overall TV allocation
- It is possible that Australia's VHF channel 0 may be phased out, as it is not appreciably used.
Channel obsolescence related to DVB-T transition
- With the introduction of digital television into Australia in 2001, VHF channels 10 and 11 were moved up by 1 MHz.
- With the introduction of Digital Television in Australia (using channels VHF 6-12 and UHF 28-69), VHF channels 0-5A will cease to be used for television when analogue television broadcasting ceases.
- This allocation change allowed a full 7 MHz for a new channel (9A). VHF channel 12 was added following the new channel 11 to compensate for the change.
- VHF Low Band DX to and from NZ may disappear with the transition to DVB-T.
[edit] NZ
Channel obsolescence issued related to DVB-T transition
- Channels 1, 2, and 3 may be made obsolete with the adoption of DVB-T, but this may not occur until 2015.
- VHF Low Band DX to and from Australia may disappear with the transition to DVB-T.
[edit] Australasian region VHF low band obsolescence issues
In some parts of the world, like Europe, the VHF TV band is used by other services because UHF has propagation qualities that are better suited for densely populated urban centres and regions.
Why VHF will remain in use in Australasia for TV broadcasting
- NZ will keep using the VHF band, as VHF has propagation characteristics that allow it to serve large regions with modest power requirements.
- However some of the NZ and Australian VHF low band channels [(0 Australia only)), 1, 2, 3] and [4, 5A Australia only] may be reallocated to bring the region into line with a more common VHF high band allocation scheme.
- Due to similar economics of broadcasting in rural Australia, it is expected that the VHF high band (above 5A) will remain in use with no appreciable changes.
- With the introduction of Digital Television in Australia (using channels VHF 6-12 and UHF 28-69), VHF channels 0-5A will cease to be used for television when analogue television broadcasting ceases.
[edit] Channel numbering issues
Currently neither Australia, New Zealand, Fiji nor Papua New Guinea intend to normalize the numbers in the channel frequency table.
[edit] VHF Frequency allocation table
DVB-T channel allocation note
- The allocation for terrestrial television must be seen in terms of uniform 7 MHz blocks after the cessation of analogue television (with a 250 kHz guardband).
- After analogue television transmissions have ceased, only the preferred main carrier wave centre frequency should be listed as DVB-T embeds both audio and video into one datastream.
[edit] UHF Frequency allocation tableDVB-T channel allocation note
[edit] Current Australian Channel Allocation by State/TerritoryThe following tables demonstrate the number of frequency allocations in each state an territory of Australia. It is interesting to note the reduction in allocation to the VHF Low band - Channel 2 remains in high use in most State Capitals as the original frequency allocation of the ABC (now ABC1). A number of channel allocations have been transferred from Chs 3,4 & 5 since the introduction of commecial FM radio broadcasting in Australia. The singular Australian odditity, Channel 5A, is also unappreciably used and will become extinct when analogue services are switched off. These allocations are likely to change considerably over the coming years as more and more stations convert their remote repeater stations to digital.
[edit] References[edit] External linksNew Zealand Australia |
