I have the updated google earth overlay for the Texas Panhandle area (including Amarillo and all current new 508) as well as select communities along I-20.
Please PM me if you desire this very comprehensive map. You will note that some areas with sirens near the southern boundary do not have locations listed. This is because I consider these towns too far south, and/or to have uninteresting siren systems. If you see places that are further into the zone of focus (i.e. Snyder) that have no locations listed, it's because these units are no longer standing.