The first election in which each media was used for campaigning

[Dancing with Myself]

The first election results in mass media were reported by that small radio station in Pennsylvania in 1920. NBC was the first network to do full results on a scale in 1928 for Hoover's landslide on the radio. CBS started competing in 1932 on the radio but they primitive compared  to NBC.

NBC first used TV as far as know for results in 1948. There are a good 10+ minutes of it on You Tube. They used chalkboards for the up to the minute numbers and did state calls. Life Magazine sponsored them. It was very primitive and I believe CBS did it too.

1952 was the first year of the computer and marked a change. Not only did CBS beat NBC good in the ratings but they had the better computer in technology (UNIVAC,) and prediction wise computer for results, plus they had a young Walter Cronkite as the lead anchor. NBC was behind and stuck with a primitive RCA computer.  The UNIVAC was off by 1% and gave Stevenson 90+ EV's while he had 89, not bad. Nowhere as bad as in 1960 where at the start of the night it projected a landslide for Nixon.

http://drum.lib.umd.edu/bitstream/1903/10504/1/Chinoy_umd_0117E_11395.pdf

This a long as hell essay but it tells about the history of election nights and goes in depth about 1952.

1956 came Huntley/Brinkley and they innovated the big studio setup and the station breaks every half hour. By 1968 the results were in color and 8 years later came the color-able nationwide maps. They had the atlas color scheme then.

British results started on TV for the first time in 1950 by the BBC. 20 years later came the first color election night.

[Nichlemn]

This thread from October-November 1984 even has its own user Walter Mitty! And if you're in the mood for some internet creeping, most of the usenet users of that era used their real names/university affiliations, so you can look up where they are today!

I Googled one of them (Rich Rosen) and found out he has his own Wikipedia article... for being a high volume Usenet poster in the 80s .

[MATTROSE94]

The first election results in mass media were reported by that small radio station in Pennsylvania in 1920. NBC was the first network to do full results on a scale in 1928 for Hoover's landslide on the radio. CBS started competing in 1932 on the radio but they primitive compared  to NBC.

NBC first used TV as far as know for results in 1948. There are a good 10+ minutes of it on You Tube. They used chalkboards for the up to the minute numbers and did state calls. Life Magazine sponsored them. It was very primitive and I believe CBS did it too.

1952 was the first year of the computer and marked a change. Not only did CBS beat NBC good in the ratings but they had the better computer in technology (UNIVAC,) and prediction wise computer for results, plus they had a young Walter Cronkite as the lead anchor. NBC was behind and stuck with a primitive RCA computer.  The UNIVAC was off by 1% and gave Stevenson 90+ EV's while he had 89, not bad. Nowhere as bad as in 1960 where at the start of the night it projected a landslide for Nixon.

http://drum.lib.umd.edu/bitstream/1903/10504/1/Chinoy_umd_0117E_11395.pdf

This a long as hell essay but it tells about the history of election nights and goes in depth about 1952.

1956 came Huntley/Brinkley and they innovated the big studio setup and the station breaks every half hour. By 1968 the results were in color and 8 years later came the color-able nationwide maps. They had the atlas color scheme then.

British results started on TV for the first time in 1950 by the BBC. 20 years later came the first color election night.

According to this video http://m.youtube.com/watch?v=r5qR5p8oPss the 1940 election returns were broadcasted over NBC's experimental station W2XBS, though the coverage was extremely primitive by modern standards. The reason why the TV coverage of the 1940 was primitive was because regularly scheduled TV broadcasts only began less than 2 years earlier on April 20, 1939 (when David Sarnoff appeared before TV cameras to dedicate the RCA pavillion at the 1939 Worlds Fair) and due to the fact that there were less than 5,000 TV sets in use in late 1940. No footage of the 1940 election returns exists because methods to record live TV broadcasts did not exist until 1946/1947, though audio clips and/or still pictures from it might exist in some form.

The coverage of the 1948 election was indeed the first time TV began to play a big role in election coverage however, though the TV audience was still fairly small at the time(only about 500,000 TV sets were in use by November of 1948). By 1952, TV coverage of elections became the norm and soon became the most trusted medium for election coverage.

[buritobr]

The first time radio was used to show the results took place in the 1920s, but in 1916, even in a close election, the winner was known on Wednesday morning. It is famous the story in which Hughes went to bed thinking that he was winner and when he woke up, he knew that he lost. This is amazing, considering how big is the US territory and the scarcity of technologies of that time: only telephone and telegraph.
However, even after big technological progress, the time needed to process the results did not reduce too much. In 1960, the election was called to Kennedy on Wednesday morning. In 1968, the election was called to Nixon on Wednesday morning. In 1976, the election was called to Carter on 3:30am in the Eastern time zone. In 2012, the election was called to Obama on 11:20pm in the Eastern time zone.

In Brazil, by constrast, which has a territory with the same size and almost the same number of voters, the time needed to process the votes reduced a lot in the last 20 years. In 1994, the last election before the introduction of the electronic vote (the last election in which all the country used paper ballots), it took six days to process 100% of the ballots (more time than in the USA in 1916!). The winner was known in the election night only because the exit polls predicted the landslide for Fernando Henrique Cardoso. In 2014, 95% of the votes had already been processed on 8pm, three hours after the polls had been closed in the first time zone and when the polls in the last time zone were closed. The media was allowed to publish the results only that time because no result can be published in Brazil while there are people still voting. The election was called to Dilma Rousseff at 8:15pm.

[MATTROSE94]

The first time radio was used to show the results took place in the 1920s, but in 1916, even in a close election, the winner was known on Wednesday morning. It is famous the story in which Hughes went to bed thinking that he was winner and when he woke up, he knew that he lost. This is amazing, considering how big is the US territory and the scarcity of technologies of that time: only telephone and telegraph.
However, even after big technological progress, the time needed to process the results did not reduce too much. In 1960, the election was called to Kennedy on Wednesday morning. In 1968, the election was called to Nixon on Wednesday morning. In 1976, the election was called to Carter on 3:30am in the Eastern time zone. In 2012, the election was called to Obama on 11:20pm in the Eastern time zone.

In Brazil, by constrast, which has a territory with the same size and almost the same number of voters, the time needed to process the votes reduced a lot in the last 20 years. In 1994, the last election before the introduction of the electronic vote (the last election in which all the country used paper ballots), it took six days to process 100% of the ballots (more time than in the USA in 1916!). The winner was known in the election night only because the exit polls predicted the landslide for Fernando Henrique Cardoso. In 2014, 95% of the votes had already been processed on 8pm, three hours after the polls had been closed in the first time zone and when the polls in the last time zone were closed. The media was allowed to publish the results only that time because no result can be published in Brazil while there are people still voting. The election was called to Dilma Rousseff at 8:15pm.

I remember reading about the 1916 Election returns being broadcasted over the radio. The results were transmitted over the experimental station 2XG, owned and operated by Lee de Forest, the inventor of the   Audion vacuum tube in 1906. At the time of the broadcast, there were maybe 7,000 radios in use.