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Finding geographic coordinates and ground elevations from on-line sites

It is possible to determine your exact geographic coordinates and elevation above sea level using resources on-line. We have tested these sites out, and they appear to be reliable and very useful!

Geographic Coordinates

The website listed below will give you much more accurate geographic coordinates than using the FCC site.

www.geocode.com/scripts/eagle/eagle.pl?cmd=td_i

Enter the street address of your proposed site and it will give you the coordinates in both decimal degrees and degrees/minutes/seconds, using the NAD-27 standard required by the FCC. With the coordinates in degrees/minutes/seconds, you can enter them in the FCC Channel Finder to determine if a frequency is available for this location.

Elevation Above Sea Level

Once you have found a frequency, you need to know the elevation of your site ABOVE MEAN SEA LEVEL to complete Section V, the Engineering part of the application. This can be determined from a U.S.G.S. 7.5 minute topographical quadrangle map for your location. These are maps prepared by the U.S. Geological Survey with precise topographical features, including geographic coordinates and terrain elevations.

The maps are available for all areas of the country, including cities. You can find them in many local libraries, at some map stores, and at many camping goods stores that cater to hikers and orienteering. You can also order them on line directly from the U.S.G.S. for a few dollars.

mapping.usgs.gov/esic/usimage/dealers.html.

You can also determine your elevation using the following website:

www.topozone.com

Enter the same geographic coordinates on the form, and this site will generate the same U.S.G.S. topographical maps on screen for the location entered. The maps on this site are very detailed graphically, so they may take some time to download based on how fast your internet connection is.

At the top left of the map page are several scales from which to choose—select the one for 1:25,000, which will give you the most resolution. At the top right, there are three choices for size—select Large. What will then appear on your screen will be the section of the map with your exact location, in the largest magnification.

The maps include major geographic features, such as mountains, lakes, rivers, hills, etc. and major man-made landmarks, such as airports, hospitals, cemeteries, parks, railroad lines, and significant buildings, streets and highways. At this scale, most of these features should be legible. Natural areas will be green; developed areas will be pink; water will be blue; and new buildings or major constructions are generally shown in purple. (these colors are consistent on ALL U.S.G.S. maps.)

If you look closely, you will also see a series of brown contour lines that snake across the maps in irregular but roughly parallel patterns. These lines follow the features of the terrain, and they indicate changes in elevation every 10 feet. Where the elevation rises steeply they will be close together, and where the ground is flatter, they will be spaced farther apart. If you follow any one of these lines, at some point you will see the line broken by a number that is a multiple of 10. This number indicates the ground elevation, or height above sea level, for that contour.

With a good pair of eyes (or a large screen monitor) you should be able to find your address and match it up with the nearest contour line. This is the height of the ground above mean sea level. Add the height of the building to this figure, and then add the height of any pole, tower or other antenna support that will go on the roof.

All these figures added together will produce the Antenna Location Site Elevation Above Mean Sea Level in feet. Convert the feet into meters and the resulting figure is the correct entry for Question 5 in Section V.

Congratulations!

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