LNB Saturation Calculator

Updated 05 November 2015

More calculators at http://www.satellite-calculations.com

Transponder EIRP dBW
Number of Transponders
(Worst case about 60 on one polarisation)
Satellite total EIRP dBW
Satellite Position
Double click on satellite to open "single satellite view" with lots of details
Satellite Position

equals West

Site Position

Latitude Degminsec
Longitude Degminsec
Azimuth Degrees
Elevation Degrees
Slant Range Km
Atmospheric Loss dB (use 0.2dB)
Downlink Frequency Mhz
Free Space Path Loss dB
Power reaching Antenna dBW
Power flux density at earthstation dBW/M^2
Antenna Diameter m
Antenna Efficiency %

Antenna Gain

Feed Loss dB
LNB Input VSWR 1: (Probably not needed 1:1 =0 dB loss)
LNB input power dBm
LNB Gain dB
LNB output power dBm
LNB 1dB Compression point dBm


This calculator calculates total LNB power for all carrieres on one polarisation. 
On a single polarisation it can be "worst case" 60 transponders.30 in lowband and 30 i highband. 
For standard Universal LNB's both highband and lowband must be taken in to consideration. For LNB's with only one local oscillator 
frequency only highband or lowband needs to be taken into consideration.

To avoid intermodulation noise in the LNB as result of saturation it is recommended that the LNB Output power is 7dB lower than the LNB's 1dB 
compression point. A good LNB has a compression point higher than +5dB. 
To find the compression point see the datasheet for your LNB.

LNB's should be designed to work with a total satelite EIRP of 70dBW without being saturated. This is extremly important to avoid LNB saturation 
when new satellites( more power) is added on a orbital position.

2001-2015 Jens T. Satre