Overview:
If you want to default the Distance dropdown item to "No limit" and have no other options available, simply paste the below code within the "Custom Javascript" editor on the "Advanced Settings" page that can be found by clicking the "Design/Layout" tab within our app, and then clicking the "Advanced Layout".
jQuery( document ).ready(function() { var limitDistance = document.getElementById('within_distance'); limitDistance.options.length = 0; limitDistance.options[0] = new Option ("No Limit", "0"); limitDistance.options[0].selected="true";
});