Dame Nellie Melba giving her famous broadcast concert from Chelmsford long-wave station on June 15th 1920
This was the heyday or me great long-wave stations with arcs or RF machine generators, operating on wavelengths most conveniently measured in miles; the longest (Bordeaux) was 14 miles. Powers were up to 1,000kW or even more. In spite of improvements, the arcs radiated a rich assortment of harmonics and 'arc hash'.
Continuous-wave sets for ships, wireless gear (including telephony) for the new airlines and commercially available direction finders were new developments.
A group of passengers about to embark for Paris on the first commercial machine (Handley Page) to be equipped with radiotelephony (1920)
The Wireless Society of London, suspended during the war, had now resumed full activity. Though by constitution an amateur body, this unique institution did in fact represent a happy mingling of amateurism and professionalism. Many of the most 'eminent wireless telegraphists', as we used to call them in our earliest days, lectured before the Society. The first five Presidents-Campbell Swinton, Erskine Murray, Admiral of the Fleet Sir Henry Jackson, Eccles and Sir Oliver Lodge-had all from before the turn of the century played distinguished parts in wireless development. The Society changed its name to Radio Society of Great Britain in 1922.