Geography is typically not a factor for larger stations and networks, as long as the person being interviewed is an expert on a particular subject.
Typically speaking, radio reporters and hosts at networks and larger stations are more interested in the quality of the interview than the interviewee’s location. They look for an expert who can provide concise, compelling answers to their questions. They are also looking for someone who is available when they need them, and if the spokesperson is being provided via a public relations professional, they seek PR pros who deliver on their promises.
For smaller, local stations, experts in the local listening demographic are ideal and are often the key to getting an interview on the air. Reporters like to feature those who know what is important to their listening audience and have ties to the local community.