Captain Henry Joseph Round MC (2 June 1881 – 17 August 1966) was an English engineer and one of the early pioneers of radio.

He also performed some experiments with transmission paths over land and sea at different times of the day and investigated direction finding, for which he used a frame antenna.

In some later experiments with cat's whisker detectors using a variety of substances, he passed current through them and noticed that some gave off light – the first known report of the effect of the light-emitting diode (LED).

produced by a junction of carborundum and another conductor when heated by a direct or alternating current, but the connection may be only secondary as an obvious explanation of the e.m.f.

H. J. RoundThe First World War broke out in 1914, and in December 1914, Round was commissioned onto the General List and was seconded to the newly established Intelligence Corps with the rank of temporary lieutenant.

[4] Using his experience in direction finding, Round set up a series of direction-finding stations along the Western Front.

Round became Chief Engineer at Marconi's Wireless Telegraph Company in 1921, but some years later, he left to set up his own consultancy.

[8] Round died in August 1966, aged 85, in a nursing home in Bognor Regis after a short illness.