I think your are missing some concepts or not fully understanding.

 1. A taxonomy is a way to group things, ie, posts. The same taxonomy can be used for several post types, so a taxonomy is not under a post.
 2. The `single` template files are used for the view of a single post. You can make a different single template for each post type, even for each individual post.
 3. The specific template for a term of a taxonomy is `taxonomy-{your_taxonomy}-{term}.php`, in your case, it would be for example `taxonomy-type-radio.php`. This template will show all posts within the term radio of the 'type' taxonomy.

I think what you really want is to use a different `single` template based on the term of the taxonomy "type" associated to a 'Ad' post. I assume **only one term of 'type' taxonomy can be selected per post**. You can use [template_include][1] filter, or more specifically, the [single_template filter][2]:

    <?php
    function get_custom_single_template($single_template) {
        global $post;

        if ($post->post_type == 'ad') {
            $terms = get_the_terms($post->ID, 'type');
            if($terms && !is_wp_error( $terms )) {
                //Make a foreach because $terms is an array but it supposed to be only one term
                foreach($terms as $term){
                    $single_template = dirname( __FILE__ ) . '/single-'.$term.'.php';
                }
            }
         }
         return $single_template;
    }

    add_filter( "single_template", "get_custom_single_template" ) ;
    ?>

Put this in the functions.php file of your theme. Don't forget to create the single-*.php for each term (single-radio.php, single-tx.php, etc)

  [1]: http://codex.wordpress.org/Plugin_API/Filter_Reference/template_include
  [2]: http://codex.wordpress.org/Plugin_API/Filter_Reference/single_template