Craigsa,
I am in the same area as you. There is a tower at the Castle, Kyalami now, but I am not sure of its exact location. I have been with Ibust from Nov 2004, and have had crap connection/speed most of the time. The only time I noticed a dramatic improvement was 2 days later the Castle tower went up, and the speeds went back to crap. Only reason I have this connection is to test VOIP on Iburst. It does not work with this kind of latency(in my area), so I have cancelled.