Echolink allows repeaters to be connected over the internet, and also allows licensed hams with computers to connect to the system directly without using a radio. So there are two ways to participate:
Find a local repeater that is connected to the Echolink system, and access that repeater with your radio.
Download, install, and run the Echolink software on ...
You still need to tune them to frequency just like any other antenna. I tuned my 18 inch to gmrs recently. And I got much better results. So my recommendation would be to get close to the wavelength you need with room to trim down the tape measure on the inside of the antenna. I think it's funny that its actual tape measure inside with numbers and all.