Satellite Internet
satsig home page

Focal length of parabolic dish

How to make inclinometer

How to find offset angle of dish

Satellite Internet discussion forum

Sub reflector adjustment

Use rear side struts

Correcting VSAT dish distortion

Antenna panel alignment

Satellite dish pointing angle calculator

VSAT information

VSAT Installation.

Explanation of antenna feed polarisation angle

Explanation of satellite links

Radio link budget calculator - for line-of-sight radio or microwave link.

Complete all white boxes and then click the calculate button to obtain results in the green boxes.

If you are not using dish antennas at one or both ends, then estimate the gain in dBi of the yagi, dipole, tin can, horn etc that you have. e.g dipole gain = 3 dBi, tin can 7 dBi, bi-quad 8 dBi, helix 12 dBi, jagi 10 dBi etc.  Input numbers into the white box for antenna diameter and keep altering the number till the antenna gain is as you want it.

Frequency GHz
Transmit antenna diameter m
Transmit antenna aperture efficiency e.g. 0.65
Transmit antenna transmit gain dBi
Transmit antenna, power at the feed W
Transmit EIRP dBW
Range km
Path (spreading) loss dB
Power flux density at receive end dBW/m^2
Bandwidth Hz
Receive antenna diameter m
Receive antenna aperture efficiency e.g. 0.65
Receive system noise temperature (antenna+LNA) K
Signal power at output of receive antenna dBm
Receiver sensitivity (see manufacturer spec e.g -80 dBm)
Receive margin dB (0-5dB=marginal, 10-15dB=good)
Receive antenna gain dBi
Receive G/T dB/K
Link C/N dB

I would be interested for anyone to evaluate this calculator and put right any errors, make suggestions for improvements etc.

General purpose satellite link budget calculator

Other satellite related pre-calculated link budgets with useful default parameters inserted (may be amended and recalculated):

Tooway Ka band out-link link budget

Tooway Ka band return-link link budget

SCPC / DAMA 8kbit/s mesh network 1.8m antennas - Skylinx

Europe to Africa - Satellite internet broadband outlink

Africa to Europe - Satellite internet TDMA return link

Digital television broadcasting - MPEG link budget

Data broadcasting or data distribution

Satellite mobile phone link budget - return link from mobile to hub


Any problems or comments please e-mail Eric Johnston
Copyright 1 Jan 1999 Satellite Signals Ltd All Rights Reserved
Last Revision: 6 October 2018