paragraph_text: Melodifestivalen 1979 was the selection for the 19th song to represent Sweden at the Eurovision Song Contest. It was the 18th time that this system of picking a song had been used. 452 songs were submitted to SVT for the competition. The final was broadcast on TV1 but was not broadcast on radio.

paragraph_text: "Long Hot Summer" is a song co-written and recorded by Australian country music artist Keith Urban. It was released in June 2011 as the third single from his 2010 album "Get Closer". The reached number one on the U.S. "Billboard" Hot Country Songs chart for the week of 22 October 2011. Urban wrote this song with Richard Marx.

paragraph_text: Juliana's Pony: Total System Failure is the fifth album by Juliana Hatfield, released in 2000. Of note about this album is that the songs "Total System Failure" and "Leather Pants" use the same music with different lyrics.

paragraph_text: Avocet is the twelfth album by Scottish folk musician Bert Jansch, released in 1979 in UK. The album was first released by Ex Libris in Denmark in late 1978 with alternate album cover and one alternate track title, although no difference in recorded content. The title track "Avocet" was inspired by the traditional song "The Cuckoo". All tracks on the album are named after a sea bird or wading bird.

paragraph_text: ``I Write Sins Not Tragedies ''is a song by American rock band Panic! at the Disco, and is the second single from their debut studio album, A Fever You Ca n't Sweat Out (2005). It was released on April 27, 2006 on both CD and 7'' vinyl. The pizzicato cello motif that the song is built upon was played by session musician Heather Stebbins. The song reached No. 7 on the United States Billboard Hot 100. This was the band's only top forty hit until the release of`` Hallelujah ''in 2015. While the song failed to hit the top 10 on the Alternative Songs chart peaking at No. 12 which was lower than their prior single, ``The Only Difference Between Martyrdom and Suicide Is Press Coverage'' which peaked at No. 5, the song's success on the Hot 100 and Mainstream Top 40 (at No. 2) charts was what made the song one of the biggest modern rock hits of 2006 and is still one of the band's most played songs on alternative radio stations to this day.

paragraph_text: Melodifestivalen 1972 was the selection for the 13th song to represent Sweden at the Eurovision Song Contest. It was the 12th time that this system of picking a song had been used. Approximately 1000 songs were submitted to Sveriges Radio for the competition. The final was broadcast on TV1 but was not broadcast on radio.

paragraph_text: Myles Goodwyn is a 1988, self-titled solo album by Myles Goodwyn, the lead singer/songwriter, guitarist, pianist, and founding member of the Canadian rock group April Wine. Two alternate versions of this album exist, with a reissue having been released with different album cover art from that of the original. Other notable differences found on the reissued version include renaming the song "Sonya". This song which had appeared on the original release is now named "My Girl". Track listings appear in a slightly different order on the reissued version as well.

paragraph_text: Song of Summer is a 1968 black-and-white television film written, produced, and directed by Ken Russell for the BBC's "Omnibus" series which was first broadcast on 15 September 1968. It portrays the final six years of the life of Frederick Delius, when he was blind and paralysed, and when Eric Fenby lived with the composer and his wife Jelka as Delius's amanuensis. The title is borrowed from the Delius tone poem "A Song of Summer", which is heard along with other Delius works in the film.

paragraph_text: "Dope Nose" is a song by American alternative rock band Weezer. It is the first single off the band's fourth album, "Maladroit". It was officially released in March 2002, though it had been performed live and in the studio during the band's 2000 summer tour comeback after hiatus.

paragraph_text: "Summer of '69" is a song recorded by the Canadian musician Bryan Adams, from his fourth album, "Reckless" (1984). The song was written by Adams and Jim Vallance, a long-time writing partner of Adams. "Summer of '69" was produced by Adams and Bob Clearmountain. It was released in June 1985 under A&M Records as the fourth single from "Reckless". "Summer of '69" is an up-tempo rock song.

paragraph_text: 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.

paragraph_text: Melodifestivalen 1975 was the selection for the 16th song to represent Sweden at the Eurovision Song Contest. It was the 15th time that this system of picking a song had been used. 10 songwriters were selected by SVT for the competition. The final was broadcast on TV1 but was not broadcast on radio.

paragraph_text: Melodifestivalen 1986 was the selection for the 26th song to represent Sweden at the Eurovision Song Contest. It was the 25th time that this system of picking a song had been used. 90 songs were submitted to SVT for the competition. The final was broadcast on TV1 and was not broadcast on radio. No orchestra was used, and instead the ten songs were broadcast as music videos. The five songs that qualified for the second round were performed live to backing track.

paragraph_text: "Don't Cry" is a power ballad by the hard rock band Guns N' Roses, two versions of which were released simultaneously on different albums. The version with the original lyrics is the fourth track on "Use Your Illusion I", while the version with the alternate lyrics is the 13th track on "Use Your Illusion II". Only the vocal tracks differ, and even then only in the verses; however, in those verses, not only are the words entirely different, but the meter and melody are also slightly different. There is also a third version, officially released only on the single for the song, which was recorded during "Appetite for Destruction" sessions in 1986. The song reached the top 10 in many countries, including number 8 in the UK Singles Chart and number 10 in the U.S. on the "Billboard" Hot 100.

paragraph_text: Melodifestivalen 1980 was the selection for the 20th song to represent Sweden at the Eurovision Song Contest. It was the 19th time that this system of picking a song had been used. 120 songs were submitted to SVT for the competition. The final was broadcast on TV1 but was not broadcast on radio.

paragraph_text: Melodifestivalen 1982 was the selection for the 22nd song to represent Sweden at the Eurovision Song Contest. It was the 21st time that this system of picking a song had been used. 90 songs were submitted to SVT for the competition. The final was broadcast on TV1 but was not broadcast on radio.

paragraph_text: ``Let It Be ''is a song by the English rock band the Beatles, released in March 1970 as a single, and (in an alternate mix) as the title track of their album Let It Be. At the time, it had the highest debut on the Billboard Hot 100, beginning its chart run at number 6. It was written and sung by Paul McCartney. It was their final single before McCartney announced his departure from the band. Both the Let It Be album and the US single`` The Long and Winding Road'' were released after McCartney's announced departure from and the subsequent break - up of the group. The alternate mix on their album Let It Be features an additional guitar solo and some minor differences in the orchestral sections.

paragraph_text: Melodifestivalen 1989 was the selection for the 29th song to represent Sweden at the Eurovision Song Contest. It was the 28th time that this system of picking a song had been used. 1,223 songs were submitted to SVT for the competition. The hostess, Yvonne Ryding, was the 1984 Miss Universe. The final was broadcast on SVT1 and was surprisingly not broadcast on radio. The show was watched by 5,328,000 people.

paragraph_text: Melodifestivalen 1974 was the selection for the 15th song to represent Sweden at the Eurovision Song Contest. It was the 14th time that this system of picking a song had been used. 10 songwriters were selected by SR for the competition. The final was broadcast on TV1 but was not broadcast on radio. ABBA went on to win that year's Eurovision Song Contest in Brighton, Sweden's first Eurovision win.

paragraph_text: "All Summer Long" is a song by Welsh musician and composer John Cale. It was released as a digital single in August 2013, while on the B-side was the song "Sandman (Flying Dutchman)" from Cale's album "Shifty Adventures in Nookie Wood" from the previous year. "All Summer Long" was released only on this single, but not on any studio album. It was recorded during the recording sessions for "Shifty Adventures in Nookie Wood".

Question: For how long did the broadcaster of Song of Summer alternate different broadcasting systems?
Answer: six months