In the Virgin Islands and Puerto Rico, full power FM stations operate at field strengths well above normal operating class parameters in the mainland. As a result, LPFM rules have always had different spacing requirements. While the protections between full power stations within PR and VI follow some really strange service and interference contours (based on the classes of BOTH stations), LPFM is a little more straightforward. However, the engineering rules are different than on the mainland. These rules may help if you are assisting with a potential applicant in Puerto Rico or the Virgin Islands. While REC has not performed any substantial research on the availability in PR/VI, there were not many opportunities during the last window. We are aware of 1 LPFM station in the VI. We will look at doing additional research on availability in the region, but for now, here’s what appears to be the solution of how they do PR/VI based on our own trial and error. LPFM stations in this area are the normal field strength (5.6 at 60dBu) for service contour and like LPFM stations on the mainland, interference contour protections vary for class B1 and B opposing stations. Like the mainland, the class B1 and B stations will have protected service contours out to 57dBu and 54dBu respectively, however all three classes (A, B1 and B) will use the same interference contours. In addition, LPFM stations are required to protect FM operations in the British Virgin Islands. All LPFM applications in PR & VI will be coordinated through the International Telecommunications Union. A foreign administration may object to the assignment. The FCC provides information on BVI FM stations which do appear in REC’s databases (look for the country code BV). It’s only as good as the information the FCC receives from the ITU and/or the BVI administration. REC does our best to protect these stations on Channel Searches but we always recommend additional investigation on applications in this area. In this document there is a list of stations that we are aware of in the BVI (but not confirmed), some are not in the FCC database and therefore not in REC broadcast services. Because PR and VI are in Zone I-A, class C, C0, C1, C2 and C3 stations are not available. Translators are limited to 250 watts at 32m HAAT (13.8km service contour).
- Class A full facilities are 6 kW at 240 meters HAAT.
- Class B1 full facilities are 25 kW at 150 meters HAAT.
- Class B full facilities are 50 kW at 472 meters HAAT. The following charts show the proper contours to use when determining protection rules for LPFM services. Remember, the 20 km buffer zone around the full power station’s service contour for co-channel and first adjacent channel is in effect in Puerto Rico or Virgin Islands.