In the FCC Rules for LPFM in section 73.807, FM translators are divided under three different "sub-classes" based on the size of their 60 dBu service contour using HAAT calculated from 12 radials. Each of these three "sub-classes" require a different amount of protection by LPFM stations. This method for protection was used to address the issue that not all translators are created equal and to provide a distance separation method to protect translators instead of using the customary prohibited overlap model that translators use to protect other translators and LPFM.
The FCC does not indicate these sub-classes in any of their database products. It is up to the user of the data to figure out the sub-class. As a convenience, REC has been making an effort to identify translator sub-class as a courtesy.
Many years ago, REC was promoting changes to 73.807 of the rules to allow translators to be divided into one of eight sub-classes based on service contour size as follows:
- D1 - service contour of less than or equal to 5.3 km
- D2 - service contour greater than 7.3 km but less than or equal to 7.3 km.
- D3 - service contour greater than 9.3 km but less than or equal to 9.3 km.
- D4 - service contour greater than 11.3 km but less than or equal to 11.3 km.
- D5 - service contour greater than 13.3 km but less than or equal to 13.3 km.
- D6 - service contour greater than 15.3 km but less than or equal to 15.3 km.
- D7 - service contour greater than 17.3 km but less than or equal to 17.3 km.
- D8 - service contour greater than 19.3 km.
For many years, our tools have carried these designators.
As REC has not been recently promoting this method of translator spacing, we are in the process of changing our program so that all translators will appear in one of three sub-classes.
- DA will be used for all translators with serice contours less than or equal to 7.3km. These are also referred to as the "lower tier" translators. During the transition in our systems, these translators will show in our systems as D2.
- DB will be used for all translators with service contours of more than 7.3km but less than 13.3 km. These are also referred to as the "middle tier" translators. During the transition, these translators will show in our systems as D5.
- DC will be used for all translators with service contours that are 13.3km or greater. These are also referred to as the "upper tier" translators. During the transition, these translators will show in our system as D8.
This change reflects only how an internal process works at REC and is not reflective of any rule changes at the FCC. The rules for protecting translators have not changed.
REC reminds all myLPFM users to verify the sub-class/tier of each translator being evaluated when determining LPFM availability. If a channel report shows a translator on the same channel that is less than 39km away, a first adjacent channel translator that is less than 28km away and a second adjacent channel translator less than 21km away, REC recommends that you check the translator's ERP and HAAT using the REC Broadcast Query tool and then using the FCC CURVES tool, verify the size of the service contour to determine if whether it is a lower tier (less then or equal to 7.3 km), middle tier (more than 7.3km but less than 13.3km) or an upper tier (13.3km or more) translator. REC is not responsible for any errors in determining the sub-class of a translator.
Thank you for your support over the years.
