For towers on existing structures such as buildings, base of tower at ground or atop structure. I assume base of tower would the ground level of the structure the tower is built on.
bridge
All the 1A's I've done on existing structures which is many are lat, long, ground elevation, and highest point. Say they are installing an antenna array on an existing building, i give ground elevation at first floor, lat., long of antenna array on rooftop and height of building. Ie highest point. Sometime the client asks for parapet height and roof top height, but not required for 1A.
Also if the top of the proposed structure is higher than the existing structure then you would want to list that height as well.
bridger48, post: 336559, member: 6251 wrote: For towers on existing structures such as buildings, base of tower at ground or atop structure. I assume base of tower would the ground level of the structure the tower is built on.
bridge
The telecom companies I do them for require natural ground, top of structure and tallest appurtenance (elevator housing or other antennas)