This program can be used to generate up to two concentric circles which will be overlaid on a map of the United States or a portion thereof. The map and circle center is determined from latitude and longitude coordinates given degrees minutes seconds or decomal degrees. With some preliminary work on your part, these maps can be used to:

• Approximate the protected service and interfering contours for an FM or TV station.
• Show areas which meet the minimum spacing criteria for FM stations, e.g., for allotment studies for FM commercial stations prior to filing a petition for rulemaking.
• Find the location of the blanketing interfering contour (see Section 73.318).

• Plot the locations of AM, FM, and TV stations (or those of other services) with respect to a given set of coordinates.

• Show streets in the vicinity of a station's transmitter site, e.g., within 3.2 km (two miles) of an AM directional station (see Section 73.1692).

• Show the location of your home with respect to the protected service contour of favorite FM or TV stations.

The generated maps are returned as GIF files into IFRAMES. Most newer browsers support the IFRAME HTML tag, some better than others. Depending on which browser you use, you may have to (1) right-click and save the map image as "your-filename.gif" to your hard drive, the open the file to print it (Internet Explorer), (2) print the image via File | Print (Opera), (3) or print the HTML page (Firefox)..Other browsers may react differently, so some experimentation with printing may be needed.

It must be noted at the outset that this program will not generate actual service or interfering contours for radio stations. Actual signal strength contours for FM or TV stations are affected by the terrain in a given direction, as well as the irectional pattern (where used) of the broadcast station. Nevertheless, by using circles in lieu of contours, a particular contour of interest may be approximately located. The circle data will be close to the nondirectional contour data over flat terrain, but may be less so in mountainous terrain. Also, actual coverage will usually be less than predicted here if a directional antenna is in use. Please keep these facts in mind when reviewing the map plots generated by this program.

This program employs the Census Bureau's Tiger Mapping Service to generate the map backgrounds.Because the Tiger Map servers are very busy, and due to the large size of the files sent over (over 360 points per circle), it may taje a minute or two to generate a map.

We suggest that you look at the information available at the Census Bureau's Tiger Mapping Service (particularly the FAQ page), to get an idea of the capabilities and limitations of this program. Please note that not all options available for the Tiger maps have been implemented in the FCC's circle plot program. After sending the initial data, you will have the option of modifying the data to recenter oe resize the map. The initial circles will be scaled to fit the map, if no specific map size is entered;

Before using this program, please confirm the cache on your browser is set to verify documents every time.

Resources you may want to refer to before creating a map include:

• FM Query for the ERP and HAAT of FM stations;

• TV Query for the ERP and HAAT of TV stations;

• FM and TV Propagations Curves Calculations, to get the radial distance given an ERP and a HAAT for an FM or TV station;

• FM Station Classes for reference ERPs and HAATs for the various FM station classes;

• Minimum Spacing Requirements for FM Stations;

• Find Community Coordinates program;

• The US Gazetteer, at the Census Bureau at http://www.census.gov/cgi-bin/gazetteer can be used to find coordinates for individual locations, such as your community. The Map Browser at http://tiger.census.gov/cgi-bin/mapbrowse-tbl can then be used to further narrow the coordinates of a particular point such as your home. (Note: this map retrieval method was not used here because the retrieved map cannot easily be resized as needed.) Please be aware that the FCC does not warrant the accuracy of the Census Bureau's data, although as of this time we are not aware of anomalies in that data.

Comments and suggestions may be directed to Dale Bickel, dale.bickel@fcc.gov.