Schedule 3 Antenna height and average ground height

(subsection 5(1), section 11, item 1 of Part 3 of Schedule 2)

Part 1 Effective antenna height of a transmitter

1\. If:
(a) subject to item 2, hgt is the vertical height in metres of the phase centre of the fixed transmitter’s antenna measured with an error of less than 5 parts in 100 and relative to the point:
(i) located on the line of intersection between the external surface of the structure supporting the antenna and the surface of the ground or sea; and
(ii) having the lowest elevation on that line; and
(b) subject to item 3, hs is the sum of:
(i) the DEM-3S cell height of the location of the radiocommunications transmitter as defined in Schedule 1; and
(ii) hgt; and
(c) ![](image.008.png) is the average ground height of the DEM-3S at each m-increment on each n-radial as calculated in accordance with Part 1;
then the effective antenna height ![](image.003.png) is:
(d) except where paragraph (e) applies: ![](image.009.png) (as shown in Diagram 1);
(e) if ![](image.009.png) is less than ![](image.010.png): ![](image.010.png).
2. For a group of radiocommunications transmitters, hgt is the greatest of the hgt for each individual transmitter in the group, calculated in accordance with this Part.
3. If the seconds component of the latitude or longitude of the radiocommunications transmitter as defined in Schedule 1, plus 1.5, has a modulus of zero when divided 3, then hs is the sum of:

(a) hgt; and

(b) the maximum height of the adjacent DEM-3S cells.

Note Additional information for the purpose of calculating hs where the latitude or longitude of the radiocommunications transmitter as defined in Schedule 1 corresponds to a DEM-3S cell boundary is provided in the document titled ‘Digital Elevation Model Interpretation’ available, free of charge, on the ACMA’s website at www.acma.gov.au.

Diagram 1 Calculating effective antenna height

Diagram 1 shows the calculation of effective antenna height

Part 2 Average ground height

1. The average ground height at the mth increment on the nth radial is calculated as follows:
Step 1: Determine the associated latitude and longitude of the mth increment on the nth radial (lmn, Lmn) as calculated in Part 3 of this Schedule.
Step 2: Identify the DEM\-3S cell represented by (lmn, Lmn).

Note: See item 2 below for identifying the DEM-3S cell in a particular case.

Step 3: Bound the identified DEM-3S cell with the 8 adjacent DEM-3S cells in a 3 x 3 matrix and obtain each DEM-3S cell height attribute (as shown in Diagram 2).
Step 4: Determine the average value of the 9 DEM-3S cell heights for each cell in the the 3 x 3 matrix.