Limit search by channel on the form rather than the results template I'd like to use the same results template for all of my search functions so I'm wondering if it's possible to limit the search to a specific channel i.e. news or calendar in the form rather than in the results template.

Thanks!
You'd do it just like querying for any other element in Craft.  i.e.

{% set results = craft.entries({
    search: query,
    section: 'news'
}) %}