Continuous internet speed test

I need to test the internet speed continuously. I'm configuring antenna for my router and it will be very useful. So far I'm using terminal and ping command which runs continuously/automatic but I'd like to have the same not only for latency but also for the speed of connections. There are tons of applications like speedtest.net but I cannot find one which tests connection speed automatically by generating some dummy traffic and displays test results continuously.

Honestly I am not sure if one exists -- I have yet to find one.

You could try using this site -- thinkbroadband :: Download Test Files -- and choose the 1 GB file. That way it can keep downloading as you walk around and you can see the various speeds.