Advice Needed Amos 3 footprint covrage below the horizon?

SEOShamsher

Member
My Satellite Setup
Past setup:
• 8-ft dish covering 68.5°E, 75.0°E (Ku), 78.5°E, 83.5°E, 90.0°E, 93.5°E (Ku), 100°E, 105.5°E, 115.0°E
• 6-ft dish at 49.0°E
• Receivers: COSHIP CDVB2000B, Dish TV Zinga

Current status:
Sold all equipment — want to start again from scratch.
My Location
Ludhiana, Punjab, India
I was checking the beam footprint map for Amos 3 (now replaced by Dror 1) at 4°W and noticed something that confused me.

As you can see in my screenshots, there is a clear horizon limit line running vertically near my location in Ludhiana, Punjab, India. Everything to the right of that red line northern India, is technically outside the geometric horizon for this satellite. Elevation there is below 0°

e725ed69-0480-407e-b5ee-10931da8faa9.webp16e31ae4-c3e5-4c9e-8694-31cceae21d2f.webp

But here is the strange part — the satellite footprint coverage map still shows signal coverage (red shading) extending well into that below-horizon zone. Almost all of areas in red are -0.5° BELOW THE HORIZON!


My questions:


  1. Is this a mapping error in the footprint , or is there a real technical reason why coverage is shown in areas that are geometrically below the satellite's horizon?
 
Due to atmospheric influences, the satellite signal near the horizon curves a bit along the earth's surface.
So it seems you can receive satellites slightly below the horizon.
I've no experience with it, though.

Greetz,
A33


Added: Did you open three topics about this same subject? Why?
It rather diffuses the information, I would say...
 
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Due to atmospheric refraction its perfectly possible to receive transmissions that are actually marginally below the horizon if you are very lucky - its not guaranteed & conditions have to be just right.
 
Thanks all for your inputs. It really helped me to confirm my findings.
 
Unfortunately no transmissions anymore on Amos 3 and is in inclined orbit, although that also means twice a day it probably will be above horizon. All is switched to Dror 1 and no footprints from Dror 1 are known afaik, but they are probably quite similar.
For Amos 3 Satbeams says 75 cm (47 dBW) needed. You'll probably need more because of the low elevation.
Middle East TV on 11212 V should be the easiest to receive with DVB-S and FEC 1/2.
 
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