Why Dish Size Matters
A satellite dish works like an antenna — the larger its reflective surface, the more signal energy it can collect and focus onto the LNB (Low-Noise Block downconverter). Bigger dishes are especially important when you're at the edge of a satellite's coverage footprint, in a rainy climate, or trying to receive weak transponders.
Choosing a dish that's too small results in pixelation, signal dropouts, or complete loss of picture. Choosing one that's too large wastes money and makes installation harder. Getting it right is a balance.
Key Factors That Determine Dish Size
1. Your Geographic Location
Every satellite broadcasts with a specific footprint — a map showing signal strength (measured in dBW) across its coverage area. Signal strength decreases the further you are from the satellite's main beam. A dish that works perfectly in Central Europe may be too small in Northern Scandinavia or North Africa.
2. The Target Satellite
Different satellites at different orbital positions have varying beam strengths. Some satellites have narrow, high-power spot beams; others have wide continental beams with lower average power. Check the specific satellite's footprint map before deciding on a dish size.
3. Local Obstructions and Environment
- Trees and buildings: Obstructions between the dish and satellite reduce effective signal. A larger dish can partially compensate.
- Rainfall: Heavy rain absorbs Ku-band signals (a phenomenon called "rain fade"). In tropical or high-rainfall regions, a larger dish provides margin against this.
- Roof mounting vs. ground mounting: Higher mounting positions typically have better line-of-sight.
4. Number of LNBs / Multi-Satellite Reception
If you plan to use a motorised dish or a multi-LNB setup to receive multiple satellites, a larger dish is generally recommended to maintain adequate signal across all positions.
General Dish Size Guidelines
| Location | Satellite (Example) | Recommended Dish Size |
|---|---|---|
| Central Europe | Hotbird 13°E / Astra 19.2°E | 60–75 cm |
| Western Europe (UK, Ireland) | Hotbird 13°E | 85–100 cm |
| Western Europe (UK, Ireland) | Astra 28.2°E (Sky UK) | 60–75 cm |
| Scandinavia | Astra 19.2°E | 90–120 cm |
| North Africa | Hotbird 13°E | 100–120 cm |
| Middle East | Nilesat 7°W / Arabsat | 60–90 cm |
| Sub-Saharan Africa | Intelsat / SES | 120–180 cm |
These are approximate guidelines. Always consult the satellite operator's footprint data for precise recommendations.
Dish Shape: Offset vs. Prime Focus
- Offset (most common for home use): The LNB is mounted to the side of the dish's focal point. The dish appears to point higher than it actually is. Easy to install, good performance for Ku-band.
- Prime focus (larger dishes): The LNB sits directly in front of the dish centre. More common for C-band and large Ku-band setups. Requires more precise alignment.
Quality Over Size
A well-made 75 cm dish will often outperform a cheap 90 cm dish. Look for dishes with smooth, accurate parabolic profiles and robust LNB mounting arms. Poorly formed reflectors scatter signal instead of focusing it. Stick to reputable brands like Gibertini, Triax, Inverto, or equivalent quality manufacturers in your region.
Final Recommendation
When in doubt, go slightly larger than the minimum recommendation. An extra 10–15 cm in diameter adds a meaningful signal margin and costs relatively little. This "headroom" makes your installation more reliable through bad weather and seasonal signal variations.