4 metres

The 4-metre (70 MHz) band is an amateur radio frequency band in the lower very high frequency (VHF) spectrum.

The 4-metre band has a unique character and because very few countries have an allocation there, very little dedicated commercial amateur equipment is available. Therefore, most amateurs active on the band are interested in home construction or modification of private mobile radio (PMR) equipment. As a result, there is a lot of camaraderie on the band and long ragchews are the norm, as long as there is some local activity.

Before World War II, British radio amateurs had been allocated a band at 56 MHz. After the war ended, they were allocated the 5-metre band (58.5 MHz to 60 MHz) instead. This only lasted until 1949, as by then the 5-metre band had been earmarked for BBC Television broadcasts.

In 1956, after several years of intense lobbying by the Radio Society of Great Britain (RSGB), the 4-metre band was allocated to British radio amateurs as a replacement for the old 5-metre band allocation. For several years the 4-metre band allocation was only 200 kHz wide—from 70.2 MHz to 70.4 MHz. It was later extended to 70.025 MHz to 70.7 MHz. The band limits were subsequently moved to today's allocation of 70.0 MHz to 70.5 MHz.

In addition to the traditional users (United Kingdom, Gibraltar and the British Military Bases in Cyprus), an increasing number of countries in Europe and Africa have also allocated the 4-metre band to radio amateurs as a result of the decline in VHF television broadcasts on the 4-metre band. Movement away from the old Eastern European VHF FM broadcast band and migration of commercial stations to higher frequencies have led to slow but steady growth in the number of countries where 4-metre operation is permitted.

Whilst not formally allocated at an ITU or Regional level, in Europe CEPT now recognises the increased access to 70 MHz by radio amateurs with footnote 'EU9' which has helped underpin further growth. In July 2015 CEPT updated this footnote to fully recognise it as a formal secondary allocation:

In practice this ranges from 70 MHz to 70.5 MHz in the United Kingdom, with other countries generally having a smaller allocation within this window. In most countries the maximum power permitted on the band is lower than in other allocations to minimise the possibility of interference with non-amateur services, especially in neighbouring countries. A table with national and regional allocations is pusblished and regularly updated on the Four Metres Website.

...
Wikipedia