Television frequency allocation has evolved since the start of television in Australia in 1956, and later in New Zealand in 1960. There was no coordination between the national spectrum management authorities in either country to establish the frequency allocations. The management of the spectrum in both countries is largely the product of their economical and political situation. New Zealand didn't start to develop television service until 1965 due to World War 2 and its economic harm in the country's economy.
The demand and planning for television in Australia intensified after WW2, with the Chifley government first favouring the existing British model (state monopoly) in 1948, and New Zealand used a similar model during the introduction of television in the 1960s. Private broadcasting did not come to the country until the 1980s, but there was no spectrum expansion to cope with the new arrangement.
History
Australia
Australian television broadcasting commenced in 1956 in Melbourne and Sydney to coincide with the 1956 Summer Olympics.
Three stations commenced operations on a ten-channel spectrum arrangement: the ABC operating in the VHF low band (VHF Ch 2), and the commercial stations operating in the VHF high band (VHF Ch 7 & 9). At the outset, commercial stations were independently owned, but due to economic forces network affiliations were soon established.
This pattern of television spectrum allocation was replicated in most of the state capital cities over the subsequent decade, with the exception of Hobart (one commercial service on VHF 6) and eventually Darwin (both the ABC and the commercial service were allocated in the VHF high band).
Geographical conditions differed in Melbourne and Sydney. The Melbourne transmission towers were located on the nearby Mount Dandenong, and their elevation and broadcasting power on an otherwise relatively flat terrain meant that the broadcasting signal could be received for some considerable distance, although there were some areas that experienced reception difficulties due to hills or buildings.
In the Sydney "basin" (formed by the Blue Mountains) the broadcast towers were collocated on the original studio sites, and given the undulating geography of Sydney there were many areas that experienced reception difficulties. The Blue Mountain terrain in the West of Sydney meant that capital city broadcasting did not penetrate into the hinterland of NSW, unlike that of Melbourne. It is possible that the penetration of weak signals into the Victorian hinterlands hastened the demand for the establishment of regional television stations, which commenced in 1961.
The Australian Government restricted regional television broadcasting to one commercial service and a repeater station of the national broadcaster from the capital city ABC station. Regional television stations tended to be allocated to VHF 6, 8 or in some cases 10.
FM allocation artifacts
The United Kingdom and New Zealand until recently shared an FM broadcasting allocation of 88.0 MHz to 105.0 MHz. Since the early 2000s both nations have full use of the standard FM band due to reallocation activities related to their separate implementation strategies for digital television.
This smaller FM Band allocation (less than 20 MHz: 88 MHz to 108 MHz as is used in most countries) can be traced to the 405-line television system's VHF allocation block. The UK adopted the 405-line system but NZ did not. The slightly smaller allocation only posed problems for the UK for its densely populated metropolitan regions, but NZ had few problems with the smaller allocation.
NZ's allocation for FM remained smaller as if NZ had adopted the 405-line system. New Zealand considered adopting the 405-line system in the late 1950s to early 1960s but adopted PAL instead. This impacted the frequency allocation block for FM broadcasting making it smaller. New Zealand's FM frequency allocation issue was not fixed until the late 1990s, when the FM band was expanded to the standard full 20 MHz block. As of the mid-2010s NZ totally abandoned its VHF band for UHF channels above 25.
Differences in frequencies
There is a frequency offset for many DTV channels between Australia and NZ, because of historical reasons relating to the introduction of PAL.