A Timeline of UK Valve and Broadcasting Development


T. A. Edison

Accidental discovery of emission and rectifier effects (vacuum tube)

Friday, April 30, 1897

J.J. Thompson

Discovery of the corpuscle (electron). The name electron had been suggested in 1891 by Professor Stony for his conjectured electric particles in a chemical context. ελεκτρον (electron) -  is Greek for amber and is the root from which 'electricity' is derived.


P. Lennard

Use of an electrostatically operating auxiliary electrode with cathode-ray experiments


O. W. Richardson

Electron emission theory explains Edison effect


C. Hewitt

Relay effect by magnetic arc control (controlling an ionic discharge)


P. Lennard

Use of wire-mesh grids to electrostatically control electron velocity

A. Wehnelt

Discovery of the excellent emission qualities of alkaline earths (oxide cathode)


J. A. Flemming

Using the electron tube as a high-frequency detector


R. v. Lieben

Vacuum amplifier tube with magnetically controlled electron flow

L. de Forest

Detector tube with plate control


L. de Forest

Audion patent (single-grid tube)


J. A. Flemming

Tungsten filament for electron tubes


R. v. Lieben

Control grid (amplifier with mercury vapor filled tube)

J. Langmuir

Improving emission by thoriated-tungsten filament


O. v. Bronk

Radio-frequency amplifier



Mass production of Lieben tubes

L. de Forest

Regeneration - positive feedback

G. Leithäuser

Supressor-grid arrangement for cathode-ray experiments


J. Langmuir

Space-charge grid circuit

A. Meißner

Oscillator by positive feedback

J. Langmuir

Significance of high vacuum for the space charge


W. Schottky

Increasing transconductance by dual control


Indirectly heated cathode


W. Schottky

Protective grid


A. W. Hull

Screen grid

June 15, 1920

First public broadcast in U.K. from the Marconi works in Chelmsford

Feb. 14, 1922.

2MT Marconi transmitter at Writtle, Essex, began first regular public entertainment program.

Aug. 1922.

Cossor patent P1 valve.

Nov 1, 1922

BBC type approval marks (stamp regulations) introduced on all British sets and valves.


Nov. 14, 1922.

London (2LO), first British broadcasting station, commenced.

Nov. 15, 1922.

First programmes broadcast from the London, Birmingham, and Manchester stations.

Late 1922.

Marconi-Osram Dull Emitter valves introduced - see DE4 .

Dec. 15, 1922.

British Broadcasting Company, Ltd., registered.

Jan. 8, 1923.

First outside broadcast, " The Magic Flute " (Mozart), from Covent Garden.

Feb. 2, 1923.

Cardiff station opened.

Feb. 16, 1923.

First broadcast play.

Feb. 17, 1923.

First charity appeal by wireless.

Mar. 3, 1923.

Glasgow station opened.

May 1, 1923.

First broadcast from Savoy Hill.

Sept. 12, 1923.

Sir E. Rutherford's address to the British Association at Liverpool simultaneously broadcast from all B.B.C. stations.

Oct. 1, 1923

Valve royalties abolished. Type approval and 'sealed sets' ended.

Oct. 10, 1923.

Aberdeen station opened.

Oct. 17, 1923.

Bournemouth station opened.

Dec. 24, 1923.

Newcastle station opened.


Mullard half owned by N. V. Philips Gloeilampenfabrieken of Eindhoven, Holland.

April 13, 1924.

First broadcast from St. Martin-in-the-Fields, conducted by the Rev. Dick Sheppard.

April 23, 1924.

First broadcast by King George V and King Edward VIII (then Prince of Wales) at opening of Wembley Exhibition.

Aug. 15, 1924.

Hull relay station opened.

Sept. 1924.

BBC marks changed.


Jan. 1, 1925

BBC mark no longer compulsory for BBC companies.


George Uhlenbeck and Samuel Goudschmidt

Discovery of electron spin

Mullard intoduce the PM series of azide process valves. - see PM3.

July 21, 1925.

First transmission from Chelmsford, 5XX, B.B.C. high-power experimental station.

July 27, 1925.

Daventry 5XX officially opened.


The British Radio Valve Association (BVA) formed from the Valve Association. Companies involved included  A.C. Cossor, Edison Swan, GEC, Marconiphone, Mullard and Standard.



Suppressor grid (pentode)

Jan. 31, 1926.

Rugby telegraph station opened.


N. V. Philips Gloeilampenfabrieken become sole owners of Mullard.


Tetrode introduced ?PM12?

Late 1927.

Use of BBC marks had died out.


Pentodes and 5 pin base introduced


A.E.I. formed from Edison Swan (Edswan), BTH (Mazda) and Metrovick (Cosmos).

Sept. 16, 1929.

First BBC Regional station, Brookmans Park, opened.

Mar. 9, 1930.

First dual transmission from Brookmans Park.

Mar. 30, 1930.

B.B.C. commence television broadcasts.


K. Steimel


Mar. 13, 1932.

First programme from Broadcasting House.

Dec. 9, 1932.

Empire Broadcasting from Daventry began.


K. Steimel


Oct. 7, 1934.

Droitwich station opened.

Oct. 12, 1936.

Burghead transmitting station opened.

Feb. 1, 1937.

Penmon (Anglesey) transmitting station opened.

July 4, 1937.

Washford transmitting station opened.

Oct. 19, 1937.

Stagshaw transmitting station opened.

© Andy Cowley, 2005    Home