hi, i am looking for a gps antenna to connect to a topcon x20. I was going to use a usb type one but there is no cd rom on the x20 to download the software. I have an old yara n sensor [the blue one] and there is no gps in it and i was hoping to get it up and going this season. i guess its very out dated now but as i have it i wanted to use it and see how it performs.