A riser diagram shows how the TV signal travels from the headend to every outlet. Reading it lets consultants check, before installation, whether a proposed design delivers enough signal everywhere.
Outlet level = amplifier output − cable losses − splitter losses − tap through losses − tap loss − drop cable and outlet loss. Use manufacturer data for the actual cable at the highest frequency in use. Target 65–75 dBµV at every outlet.
| Step | Item | dB | Remaining (dBµV) |
|---|---|---|---|
| 1 | Amplifier output | — | 108 |
| 2 | Trunk 20 m | −3 | 105 |
| 3 | 2-way splitter | −4 | 101 |
| 4 | Riser to floor | −5 | 96 |
| 5 | Upstream tap through losses | −4 | 92 |
| 6 | Tap loss | −16 | 76 |
| 7 | Drop 15 m and outlet | −4 | 72 |
Calculation table at the highest frequency, cable losses matching the specified cable, nearest and farthest outlets both in range, amplifier output within the manufacturer's limit, margin for connectors and ageing.
