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This worksheet may be used to calculate your repeater transmitting antenna's Height Above Average Terrain (HAAT). This data must be supplied in order to properly coordinate your repeater.
***For the FCC HAAT calculator, click here.***
***NOTE: The FCC calculator uses meters, not feet.***
Information Needed:
- Exact Station Location (Be sure you convert GPS readings to Degrees, Minutes, and Seconds. NO decimals!):
______ Degrees ______ Minutes ______ Seconds North Latitude
______ Degrees ______ Minutes ______ Seconds West Longitude
- Transmit site ground elevation above sea level: ________ Feet
- Height of center of antenna above the ground: ________ Feet
- Antenna Make and Model: ______________________________________
- Identification of topographical map used: ____________________
- On the topographical map, plot 8 radials at 45 degree increments, centered on the transmitter location. Then plot 5 circles at 2-, 4-, 6-, 8-, and 10-mile radii, centered on the transmitter location. Determine the ground elevations at the 40 points of intersection of the 8 radials and 5 circles. Enter these into Table I. (See Figure 1 at the bottom of this document).
Table I
+--------------------------------------------------------------+
| | Radial |
| Circle +-----------------------------------------------+
| Radius | 0 | 45 | 90 | 135 | 180 | 225 | 270 | 315 |
+--------------------------------------------------------------+
| 2 miles | | | | | | | | |
+--------------------------------------------------------------+
| 4 miles | | | | | | | | |
+--------------------------------------------------------------+
| 6 miles | | | | | | | | |
+--------------------------------------------------------------+
| 8 miles | | | | | | | | |
+--------------------------------------------------------------+
| 10 miles | | | | | | | | |
+--------------------------------------------------------------+
- Determine antenna height above sea level:
Transmit site ground elevation: ____________ feet
Add antenna height above ground: +____________ feet
Equals antenna hieght above sea level: =____________ feet
- Determine average ground elevation:
Add the ground elevation of all 40 points in Table I: ________
Divide by 40 / 40
Equals average ground elevation =________
- Now calculate antenna HAAT:
Antenna height above sea level: _________
Minus average ground elevation: - _________
Equals antenna HAAT: = _________
Figure 1:
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