It was used on CW kind of like on the net it is common to use "lol" for laughing. Over time people have brough the CW Q-signals and "hi hi" to phone. As I started on the local 2 meter repeaters I heard "hi hi" used a lot in my early days of radio. So I picked up on it. I try to avoid it, but sometimes it slips out.. bad habit. .... .. .... ..