5KA was an AM station in Adelaide (population then around 800,000), the capital city of South Australia. It eventually went to FM as KAFM, now Triple M Adelaide.
The mp3s were available for a while at the now defunct 5KA Reunion site (2001), along with dozens of other 5KA sound files from the 1950s to the 1990s.1
An archived version of 5KA Reunion can be seen at Pandora, the Australian web archive. If you go here you will be redirected to the exact page. Fortunately, the audio files are still accessible: it's a treasure trove!
It's a shame that we have no thriving aircheck2 sites in Australia. For the US there are many such sites, notably ReelRadio's Top 40 Depository where you can listen to hundreds of historic audio clips from all over the country (paid sub required). For the UK, for example, the Pirate Radio Hall of Fame has numerous airchecks from the pirate stations (including the voices of a surprising number of Australian deejays).
My tattered copy of the Australian Radio Almanac (c.1968), lists only Stuart Jay under 5KA. (The 5DN entry has details of eight announcers: maybe they paid up.) Mike Fewster, heard below on Breakfast at 5KA, is listed under 5KA's country affiliate 5RM in Renmark.
The 5KA Reunion site also had a page packed with jingles, including some from the 1960s created in the US by the PAMS organisation. Listeners to other stations around the world might recognise them, with the callsign of their local station substituted. I have posted one example from 5KA.
5KA 1968 - Mike Fewster [Breakfast].mp3
5KA 1968 - Jim Slade [Drive].mp3
5KA 1968 - Ian Sells [Night].mp3
5KA 1968 - Stuart Jay [Late Night].mp3
5KA 1968 - Lawrie Bruce [Midnight-Dawn].mp3
5KA jingle 1960s.mp3
1. At this YouTube page, Jim Slade recalls that the 1968 set of 5KA airchecks was prepared as a showcase for prospective advertisers. This explains the announcer who introduces each clip, but apart from that they do seem to be genuine recordings of on-air programs.
2. Aircheck: a recording of a radio broadcast (as opposed to a recording made for a broadcast). It can be, for example, a showcase for a professional broadcaster, or an unofficial recording made by a listener. Many CDs of artists of the past are taken from airchecks of live broadcasts. See, for example, the Wikipedia entry.