Question: For how long did the company that broadcasted Elizabeth R alternate different broadcasting systems?

full_context: Document 1: BBC Television: Baird Television Ltd. made Britain's first television broadcast, on 30 September 1929 from its studio in Long Acre, London, via the BBC's London transmitter, using the electromechanical system pioneered by John Logie Baird. This system used a vertically-scanned image of 30 lines – just enough resolution for a close-up of one person, and with a bandwidth low enough to use existing radio transmitters. Simultaneous transmission of sound and picture was achieved on 30 March 1930, by using the BBC's new twin transmitter at Brookmans Park. By late 1930, 30 minutes of morning programmes were broadcast Monday to Friday, and 30 minutes at midnight on Tuesdays and Fridays, after BBC radio went off the air. Baird broadcasts via the BBC continued until June 1932.
Document 2: Gloriana: The first performance was presented at the Royal Opera House, London, in 1953 during the celebrations of the coronation of Queen Elizabeth II. "Gloriana" was the name given by the 16th-century poet Edmund Spenser to his character representing Queen Elizabeth I in his poem "The Faerie Queene". It became the popular name given to Elizabeth I. It is recorded that the troops at Tilbury hailed her with cries of "Gloriana, Gloriana, Gloriana", after the defeat of the Spanish Armada in 1588.
Document 3: Elizabeth R: Elizabeth R is a BBC television drama serial of six 85-minute plays starring Glenda Jackson as Elizabeth I of England. It was first broadcast on BBC2 from February to March 1971, through the Australian Broadcasting Corporation in Australia and broadcast in America on PBS's "Masterpiece Theatre".
Document 4: The Crown (TV series): The Crown Genre Historical drama Created by Peter Morgan Starring Claire Foy Matt Smith Vanessa Kirby Eileen Atkins Jeremy Northam Victoria Hamilton Ben Miles Greg Wise Jared Harris John Lithgow Alex Jennings Lia Williams Anton Lesser Matthew Goode Theme music composer Hans Zimmer Composer (s) Rupert Gregson - Williams Lorne Balfe Country of origin United Kingdom United States Original language (s) English No. of seasons No. of episodes 20 (list of episodes) Production Executive producer (s) Peter Morgan Stephen Daldry Andy Harries Philip Martin Suzanne Macki Matthew Byam - Shaw Robert Fox Tanya Seghatchian Nina Wolarsky Allie Goss Producer (s) Andrew Eaton Location (s) United Kingdom Running time 54 -- 61 minutes Production company (s) Left Bank Pictures Sony Pictures Television Distributor Netflix Release Original network Netflix Picture format 4K (Ultra HD) Original release November 4, 2016 (2016 - 11 - 04) -- present (present) External links Website
Document 5: BBC Television: The two systems were to run on a trial basis for six months; early television sets supported both resolutions. However, the Baird system, which used a mechanical camera for filmed programming and Farnsworth image dissector cameras for live programming, proved too cumbersome and visually inferior, and ended with closedown (at 22:00) on Saturday 13 February 1937.
Document 6: High-definition television: Colour broadcasts started at similarly higher resolutions, first with the US NTSC color system in 1953, which was compatible with the earlier monochrome systems and therefore had the same 525 lines of resolution. European standards did not follow until the 1960s, when the PAL and SECAM color systems were added to the monochrome 625 line broadcasts.
Document 7: BBC Television: Mechanically scanned, 30-line television broadcasts by John Logie Baird began in 1929, using the BBC transmitter in London, and by 1930 a regular schedule of programmes was transmitted from the BBC antenna in Brookmans Park. Television production was switched from Baird's company to what is now known as BBC One on 2 August 1932, and continued until September 1935. Regularly scheduled electronically scanned television began from Alexandra Palace in London on 2 November 1936, to just a few hundred viewers in the immediate area. The first programme broadcast – and thus the first ever, on a dedicated TV channel – was "Opening of the BBC Television Service" at 15:00. The first major outside broadcast was the coronation of King George VI and Queen Elizabeth in May 1937. The service was reaching an estimated 25,000–40,000 homes before the outbreak of World War II which caused the service to be suspended in September 1939. The VHF broadcasts would have provided an ideal radio beacon for German bombers homing in on London, and the engineers and technicians of the service would be needed for the war effort, in particular the radar programme.
Document 8: Elizabeth II: In the 1950s, as a young woman at the start of her reign, Elizabeth was depicted as a glamorous "fairytale Queen". After the trauma of the Second World War, it was a time of hope, a period of progress and achievement heralding a "new Elizabethan age". Lord Altrincham's accusation in 1957 that her speeches sounded like those of a "priggish schoolgirl" was an extremely rare criticism. In the late 1960s, attempts to portray a more modern image of the monarchy were made in the television documentary Royal Family and by televising Prince Charles's investiture as Prince of Wales. In public, she took to wearing mostly solid-colour overcoats and decorative hats, which allow her to be seen easily in a crowd.
Document 9: BBC Television: After a series of test transmissions and special broadcasts that began in August, regular BBC television broadcasts officially resumed on 1 October 1936, from a converted wing of Alexandra Palace in London, which housed two studios, various scenery stores, make-up areas, dressing rooms, offices, and the transmitter itself, now broadcasting on the VHF band. BBC television initially used two systems, on alternate weeks: the 240-line Baird intermediate film system and the 405-line Marconi-EMI system, each making the BBC the world's first regular high-definition television service, broadcasting Monday to Saturday from 15:00 to 16:00 and 21:00 to 22:00.
Document 10: Color television: After a series of hearings beginning in September 1949, the FCC found the RCA and CTI systems fraught with technical problems, inaccurate color reproduction, and expensive equipment, and so formally approved the CBS system as the U.S. color broadcasting standard on October 11, 1950. An unsuccessful lawsuit by RCA delayed the first commercial network broadcast in color until June 25, 1951, when a musical variety special titled simply Premiere was shown over a network of five East Coast CBS affiliates. Viewing was again restricted: the program could not be seen on black - and - white sets, and Variety estimated that only thirty prototype color receivers were available in the New York area. Regular color broadcasts began that same week with the daytime series The World Is Yours and Modern Homemakers.
Document 11: Elizabeth II: Elizabeth II (Elizabeth Alexandra Mary; born 21 April 1926) has been Queen of the United Kingdom, Canada, Australia, and New Zealand since 6 February 1952. Additionally, she is Head of the Commonwealth and Queen of 12 countries that have become independent since her accession: Jamaica, Barbados, the Bahamas, Grenada, Papua New Guinea, Solomon Islands, Tuvalu, Saint Lucia, Saint Vincent and the Grenadines, Belize, Antigua and Barbuda, and Saint Kitts and Nevis.
Document 12: The Crown (TV series): The Crown evolved out of Morgan's 2006 film The Queen and 2013 stage play The Audience. The series is intended to last 60 episodes over six seasons, with 10 one - hour episodes per season, covering Elizabeth's life from her younger years to her reign, and with new actors being cast every two seasons. Claire Foy portrays the Queen in the first two seasons, alongside Matt Smith as Prince Philip and Vanessa Kirby as Princess Margaret. Olivia Colman will take over as the Queen and Tobias Menzies as Prince Philip in the third and fourth seasons. Filming for the series takes place at Elstree Studios in Borehamwood, Hertfordshire, with location shooting throughout the United Kingdom.
Document 13: High-definition television: Since the formal adoption of digital video broadcasting's (DVB) widescreen HDTV transmission modes in the early 2000s; the 525-line NTSC (and PAL-M) systems, as well as the European 625-line PAL and SECAM systems, are now regarded as standard definition television systems.
Document 14: The Crown (TV series): The entire first season was released on Netflix on November 4, 2016, with the second scheduled to be released on December 8, 2017. The Crown has received overwhelmingly positive reception, with critics praising cast performances, direction, writing, cinematography, production values, and the relatively accurate historical accounts of Queen Elizabeth's reign. Significant praise in the first season was directed towards the performances of Foy in the leading role and John Lithgow as Winston Churchill. The series and its stars have been nominated for, and won, numerous awards, including Best Actress and Best Actor at the 23rd Screen Actors Guild Awards for Foy and Lithgow, respectively, and best drama, writing, and directing at the 69th Primetime Emmy Awards.
Document 15: BBC Television: After a series of test transmissions and special broadcasts that began in August 1936, the BBC Television Service officially launched on 2 November 1936 from a converted wing of Alexandra Palace in London. ``Ally Pally ''housed two studios, various scenery stores, make - up areas, dressing rooms, offices, and the transmitter itself, which then broadcast on the VHF band. BBC television initially used two systems on alternate weeks: the 240 - line Baird intermediate film system and the 405 - line Marconi - EMI system. The use of both formats made the BBC's service the world's first regular high - definition television service; it broadcast from Monday to Saturday between 15: 00 and 16: 00, and 21: 00 and 22: 00. The first programme broadcast -- and thus the first ever, on a dedicated TV channel -- was`` Opening of the BBC Television Service'' at 15: 00. The first major outside broadcast was the coronation of King George VI and Queen Elizabeth in May 1937.
ground_truth: six months
sub_queries: Who broadcasted Elizabeth R? Answer: BBC
For how long did the BBC alternate different broadcasting systems? Answer: six months