Annex B – Elevation Diagram of Typical Tower and Transmitting Antenna
Description of figure B1
The Figure of Annex B is an example of an elevation diagram of a typical tower and transmitting antenna. There are two examples of antenna towers in this figure. The first one at the left is a tower drawn as a vertical pole and the antenna is shown as a small vertical structure, attached to the tower. At the right, the second antenna tower is shown as a small pole mounted on the roof of a building. The second antenna is also shown as a small vertical structure attached to the pole on the rooftop. Both antennas are the same size and at the same elevation. The ground level is drawn as a horizontal line running at the base of the first tower and at the base of the building. The average elevation of terrain is drawn as a horizontal line slightly below the ground level. The mean sea level is drawn as a horizontal line at the bottom of the graphic, below the average elevation of terrain. A horizontal line runs at the top of both antenna poles. Another horizontal line runs through the vertical center of both antennas and is identified as the Radiating Center (RC). Another horizontal line runs from the top of the roof and is identified as Height of the Roof Above Ground (HRAG).
There is a bidirectional arrow between the line at the top of the towers and the line of the ground level, labeled as being the overall tower height and in this example, it is 300 meters high. Below, there is a bidirectional arrow between the line of the average elevation of terrain and the line of the mean sea level, labeled as being the average elevation of terrain and in this example, it is 190 meters high.
Next, there is a bidirectional arrow between the line of the ground level and the line of the mean sea level, labeled as being the Ground Level and in this example, it is 211 meters high.
Next, there is a bidirectional arrow between the line of the rooftop of the building and the line of the ground level, labeled as being the HRAG (Height of the Roof Above Ground) and in this example, it is 231 meters high.
Next, there is a bidirectional arrow between the line crossing the radiating center of the antennas and the line of the average elevation of terrain, labeled as being the EHAAT and in this example, it is 298 meters high.
Next, there is a bidirectional arrow between the line crossing the radiating center of the antennas and the line of the mean sea level, labeled as being the RC above mean sea level and in this example, it is 488 meters high.
Next, there is a bidirectional arrow between the line crossing the radiating center of the antennas and the line of the ground level, labeled as being the RC above ground level and in this example, it is 277 meters high.
Annex C — Emission Masks
Description of figure C1
The Figure C1 of the Annex C is a graphic showing the emission mask for DTV primary stations. The vertical axis is the attenuation in dB and runs from −110 dB to more than 0 dB. The horizontal axis is the frequency in MHz which spans over three TV channels of 6 MHz each for a total of 18 MHz. It starts at the lower edge of the first lower adjacent channel and ends at higher edge of the first upper adjacent channel.
The attenuation curve for the lower adjacent channel is a set of straight lines following the values in the table below:
| Distance from the lower edge of the channel in MHz | 0 | 1 | 2 | 3 | 4 | 5 | 5.5 | 6 |
|---|---|---|---|---|---|---|---|---|
| Attenuation in dB | −110 | −99 | −87 | −76 | −64 | −53 | −47 | −47 |
The attenuation curve for the center channel is shown as a horizontal line with a constant value of −11 dB.
The attenuation curve for the upper adjacent channel is a set of straight lines following the values in the table below:
| Distance from the lower edge of the channel in MHz | 0 | 0.5 | 1 | 2 | 3 | 4 | 5 | 6 |
|---|---|---|---|---|---|---|---|---|
| Attenuation in dB | −47 | −47 | −53 | −64 | −76 | −87 | −99 | −110 |
When using the DTV emissions mask for primary assignments:
- in the first 500 kHz from the authorized channel edge, transmitter emissions must be attenuated not less than 47 dB below the average transmitted power;
- more than 6 MHz from the channel edge, emissions must be attenuated by no less than 110 dB below the average transmitted power; and
- at any frequency between 0.5 and 6 MHz from the channel edge, emissions must be attenuated by no less than the value determined by the following formula: \[Attenuation (dB) = -11.5(delta (f) + 3.6)\]where delta (f) is the frequency difference in MHz from the edge of the channel.
(based on a measurement bandwidth of 500 kHz)
Description of figure C2
The Figure C2 of the Annex C is a graphic showing the simple emission mask for LPDTV stations. The vertical axis is the attenuation in dB and runs from −80 dB to more than 0 dB. The horizontal axis is the frequency in MHz which spans over three TV channels of 6 MHz each for a total of 18 MHz. It starts at the lower edge of the first lower adjacent channel and ends at higher edge of the first upper adjacent channel.
The attenuation curve for the lower adjacent channel follows the values in the table below:
| Distance from the lower edge of the channel in MHz | 0 | 1 | 2 | 3 | 4 | 5 | 6 |
|---|---|---|---|---|---|---|---|
| Attenuation in dB | −71 | −63 | −57 | −52 | −49 | −47 | −46 |
The value of attenuation for the center channel is shown as a horizontal line with a constant value of −11 dB.
The attenuation curve for the upper adjacent channel follows the values in the table below:
| Distance from the lower edge of the channel in MHz | 0 | 1 | 2 | 3 | 4 | 5 | 6 |
|---|---|---|---|---|---|---|---|
| Attenuation in dB | −46 | −47 | −49 | −52 | −57 | −63 | −71 |
When using the LPDTV simple emissions mask:
- in the first 500 kHz from the authorized channel edge, transmitter emissions must be attenuated not less than 46 dB below the average transmitted power;
- more than 6 MHz from the channel edge, emissions must be attenuated by no less than 71 dB below the average transmitted power; and
- at any frequency between 0 and 6 MHz from the channel edges, emissions must be attenuated by no less than the value determined by the following formula: \[ Attenuation (dB) = 46 + (\left[delta(f)\right]^2/1.44)\] where delta (f) is the frequency difference in MHz from the edge of the channel.
Description of figure C3
he Figure C3 of the Annex C is a graphic showing the stringent emission mask for LPDTV stations. The vertical axis is the attenuation in dB and runs from −80 dB to more than 0 dB. The horizontal axis is the frequency in MHz which spans over three TV channels of 6 MHz each for a total of 18 MHz. It starts at the lower edge of the first lower adjacent channel and ends at higher edge of the first upper adjacent channel.
The attenuation curve for the lower adjacent channel is a set of straight lines following the values in the table below:
| Distance from the lower edge of the channel in MHz | 0 | 1 | 2 | 3 | 4 | 5 | 5.5 | 6 |
|---|---|---|---|---|---|---|---|---|
| Attenuation in dB | −76 | −76 | −76 | −76 | −64 | −53 | −47 | −47 |
The value of attenuation for the center channel is shown as a horizontal line with a constant value of −11 dB.
The attenuation curve for the upper adjacent channel is a set of straight lines following the values in the table below:
| Distance from the lower edge of the channel in MHz | 0 | 1 | 2 | 3 | 4 | 5 | 6 |
|---|---|---|---|---|---|---|---|
| Attenuation in dB | −47 | −47 | −53 | −64 | −76 | −76 | −76 |
When using the LPDTV stringent emissions mask:
- in the first 500 kHz from the authorized channel edge, transmitter emissions must be attenuated no less than 47 dB below the average transmitted power;
- more than 3 MHz from the channel edge, emissions must be attenuated by no less than 76 dB below the average transmitted power; and
- and at any frequency between 0.5 and 3 MHz from the channel edges, emissions must be attenuated by no less than the value determined by the following formula:\[ Attenuation (dB) = 47 + 11.5 (delta(f) -0.5)\]where delta (f) is the frequency difference in MHz from the edge of the channel.