![DishGainAndBeamwidth.jpg](./download/file.php?id=747&sid=31101dda8bb6f5e1c18c6fd7c1c93184)
- DishGainAndBeamwidth.jpg (18.31 Kio) Vu 53532 fois
Reports at 2.5 and 4 degrees show the signal can be picked up above 1000KM
Based on the calculations in this document
http://www.amsat.it/Amsat-Italia_HamTV.pdfThe link system was designed for 1000KM range.(with 7dB margin at this range)
However the dish size used was 90cm and downconverter gain was put as 35dB,
In reality the recommended system ends up with:
Dish 90cm=24.3dB --> 1.2M (120cm) 26.6dB = +2.3dB
Pre-amp 35dB --> 48dB(my unit typically 40dB) = +13dB (also interference amplified)
With no interference we may have 2.3+13=15.3dB more signal than calculated. We also have the 7dB margin,
meaning at 1000Km we should be 23.3dB above link budget. Reports of signal picked up with an omni directional antenna on a high pass would confirm with low interference noise, the signal is quite strong.
Those calcultions do not take into account things like
-Interference from Wifi or other signals (detected myself up to 60dB above noise)
-Losses from pointing innacuracies, rotator not tracking 100%.
The dish 3dB beamwidth is 8.4 Degrees so we need to point very accurately (+/- 4 degrees total error)
-Cable/connector losses