The default search in Chrome 18 is
{google:baseURL}search?{google:RLZ}{google:acceptedSuggestion}{google:originalQueryForSuggestion}{google:searchFieldtrialParameter}{google:instantFieldTrialGroupParameter}sourceid=chrome&ie={inputEncoding}&q=%s
How can I modify the search parameters to ignore the location, like in http://www.google.com/ncr