Goal line technology or just the TV already there?

Another weekend, another goal controversy involving Motherwell. This week they were denied a goal clearly over the line versus Dundee (denying them a draw and a point and giving Dundee a win and two extra precious points). Last week there was the phantom "goal" for Motherwell versus ICT. In the lottery of glaring referee gaffs, Motherwell were winners last week, losers this week. We were effectively the losers both weeks. OK goal line technology is maybe expensive to instal but rugby just uses TV replays. Why can't we? There are TV cameras at every Scottish top flight game and we already have trial by Sportscene. Limit the TV challenges/calls to 3 (or less) per game per team a bit like tennis so there's not too much game interruption.