Question: For how long did Raphael Rowe's place of employment alternate different broadcasting systems?

full_context: Document 1: Raphael Rowe: Raphael Rowe is an investigative journalist, best known for his work with "BBC Panorama". Rowe was convicted in 1990 of murder and a series of robberies as part of the M25 Three. After twelve years in prison, the convictions of Rowe and his two co-defendants, Michael George Davis and Randolph Egbert Johnson, were ruled "unsafe" in July 2000. They had lost their first appeal in 1993.
Document 2: 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 3: 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 4: Wali Khan Babar: Wali Khan Babar (Urdu, ; 5 April 1982 – 13 January 2011) was a Pakistani journalist working for GEO News who was killed by gunmen in the Liaquatabad area of Karachi. His murderers Saulat Mirza and Faisal Mota (who are target killers of MQM) are sentenced to death by the court on March 10, 2015. According to the Committee to Protect Journalists, Babar was the first journalist it had confirmed killed in a work-related death in 2011. Pakistan was the deadliest country for journalists in 2010. Despite the murders of several people associated with the investigation and the death of an accused, in March 2014 four people were convicted and sentenced to life imprisonment for the murder, and two others were given death sentences "in absentia".
Document 5: Child labour: Primark continued to investigate the allegations for three years, concluding that BBC report was a fake. In 2011, following an investigation by the BBC Trust’s Editorial Standards Committee, the BBC announced, "Having carefully scrutinised all of the relevant evidence, the committee concluded that, on the balance of probabilities, it was more likely than not that the Bangalore footage was not authentic." BBC subsequently apologised for faking footage, and returned the television award for investigative reporting.
Document 6: 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 7: 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.
Document 8: 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 9: 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 10: The Sun (United Kingdom): On 28 January 2012, police arrested four current and former staff members of The Sun, as part of a probe in which journalists paid police officers for information; a police officer was also arrested in the probe. The Sun staffers arrested were crime editor Mike Sullivan, head of news Chris Pharo, former deputy editor Fergus Shanahan, and former managing editor Graham Dudman, who since became a columnist and media writer. All five arrested were held on suspicion of corruption. Police also searched the offices of News International, the publishers of The Sun, as part of a continuing investigation into the News of the World scandal.
Document 11: The Sun (United Kingdom): On 6 February 2015, it was announced that Judge Richard Marks is to be replaced by Judge Charles Wide at the retrial. Two days earlier, Marks had emailed counsel for the defendants telling them: "It has been decided (not by me but by my elders and betters) that I am not going to be doing the retrial". Reporting the decision in UK newspaper The Guardian, Lisa O’Carroll wrote: "Wide is the only judge so far to have presided in a case which has seen a conviction of a journalist in relation to allegations of unlawful payments to public officials for stories. The journalist, who cannot be named for legal reasons, is appealing the verdict". Defence counsel for the four journalists threatened to take the decision to judicial review, with the barrister representing Pharo, Nigel Rumfitt QC, saying: "The way this has come about gives rise to the impression that something has been going on behind the scenes which should not have been going on behind the scenes and which should have been dealt with transparently". He added that the defendants were "extremely concerned" and "entitled" to know why Marks was being replaced by Wide.
Document 12: 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 13: 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 14: The Times: Robert Fisk, seven times British International Journalist of the Year, resigned as foreign correspondent in 1988 over what he saw as "political censorship" of his article on the shooting-down of Iran Air Flight 655 in July 1988. He wrote in detail about his reasons for resigning from the paper due to meddling with his stories, and the paper's pro-Israel stance.
Document 15: Assassination of Robert F. Kennedy: In November 2006, the BBC's Newsnight program presented research by filmmaker Shane O'Sullivan alleging that several CIA officers were present on the night of the assassination. Three men who appear in films and photographs from the night of the assassination were positively identified by former colleagues and associates as former senior CIA officers who had worked together in 1963 at JMWAVE, the CIA's main anti-Castro station based in Miami. They were JMWAVE Chief of Operations David Morales, Chief of Maritime Operations Gordon Campbell and Chief of Psychological Warfare Operations George Joannides. However, several people who had known Morales, including family members, were adamant that he was not the man who O'Sullivan said was Morales. After O'Sullivan published his book, assassination researchers Jefferson Morley and David Talbot also discovered that Campbell had died of a heart attack in 1962, six years prior to the assassination of Kennedy. In response, O'Sullivan stated that the man on the video may have used Campbell's name as an alias. He then took his identifications to the Los Angeles Police Department whose files showed the men he identified as Campbell and Joannides to be Michael Roman and Frank Owens, two Bulova sales managers attending the company's convention in the Ambassador. O'Sullivan stood by his allegations stating that the Bulova watch company was a "well-known CIA cover".
ground_truth: six months
sub_queries: What is Raphael Rowe's place of employment? Answer: BBC
For how long did the BBC alternate different broadcasting systems? Answer: six months