The Leesburg Hospital Repeater Site Survey
Performed By Dale Harrison,  K3CN and and Norm Styer, AI2C
- Repeater Antenna HAAT -
Repeater Antenna Height Above Average Terrain

     The Height Above Average Terrain for the Repeater Antenna at the Leesburg Hospital Repeater Site is surveyed and calculated to be 187.5 feets. Path profiles were created using 3-D TopoQuads by DeLorme for eight directions from the repeater site then elevations were determined with the profile routine at points located 2, 4, 6, 8, and 10 miles from the repeater. These 40 points are averaged and compared the the repeater tower base elevation of 361 feet above mean sea level and the height above ground of the antenna on the tower. For worst case situation, the antenna is assumed to be mounted at the top to the 225 foot tower.

      A word or two about the accuracy of this data is appropriate. In general, the individual numbers are well within 5 feet of the map data, the path bearings are within 0.2 degree of the intended bearing. We trust these numbers will satisfy this application.

      As can be seen from the 3-D views, the terrain to the west of the site will make communications to the west challenging. Link trials to western sites equipped with handheld transceivers are encouraged.

The Leesburg Hospital Repeater Site
Antenna Height Above Average Terrain = 361 + 225 - 398.5 = 187.5 Feet
Direction
2 Miles
4 Miles
6 Miles
8 Miles
10 Miles
Average
North
414.3
501.2
677.7
572.8
335.3
500.3
North East
245.8
222.8
202.3
295.6
318.7
257.0
East
337.6
206.4
331.1
314.0
358.0
309.4
South East
311.3
288.5
308.8
243.9
244.1
279.3
South
380.5
370.4
347.9
344.3
352.5
359.1
South West
440.7
461.9
541.3
569.1
440.6
490.7
West
467.7
465.7
418.9
516.2
466.1
466.9
North West
551.2
465.7
502.5
541.4
564.3
525.0
40-Point Average
398.5

     Several graphic screen prints from the DeLorme program are included below to illustrate the computer methods and to show each of the eight profiles. The program has a routine which will trace the path and show the elevation where your place the cursor on the path; this semi-automated method was used as a starting point to develop the above table.

 

 

 

 

 

 

 

 

Path Profiles

North Profile

 

Northeast Profile

 

East Profile

Note: Graphic data not printable but available in basic program and used above.

 

Southeast Profile

 

South Profile

 

Southwest Profile

 

West Profile

 

Northwest Profile

 

Looking East from Over Western Loudoun

Looking East from over Western Loudoun at 15 Degree Pitch

 

 

Looking East

Looking East at 15 degree pitch

 

 

Looking East from Western Loudoun at 51 Degree Pitch

Looking East at 51 Degree Pitch

 

 

Looking North from Southern Loudoun

Looking North at 15 Degree Pitch

 

 

Looking Southwest from over Central Maryland

Looking Southwest form 15 degree pitch

 

Looking West from North of DC

 

Looking West from 15 degree pitch

 

Looking West towards Winchester

 

Looking West from 15 degree pitch from over Eastern Loudoun

 

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