Link Budget Inmarsat-4 F1

Hello

Can i get the value of link budget Inmarsat-4 F1 for uplink and downlink condition?

Thank You

Sadly, Inmarsat does not like us to share the EIRP-values.

:frowning:

So how about this?

And this?

Thank You Sir :slight_smile:

:frowning:

So how about this?

And this?

Thank You Sir :slight_smile:

1 Like

Ricky very interesting.

Does any of you research tell us the smallest possible mobile antenna we could have to reliably receive a Outernet signal?

Hi,

Yes we still research, so far the minimum requirement of system to have FRAME LOCK state, the SNR should be above 3 dB in South East Asian
But we still waiting Syed responses

Hallo there,

mobile L-Band reception in the possible worst environment imaginable is at sea on a yacht.


That picture shows a professional inmarsat antenna.

https://www.jcoppens.com/ant/qfh/calc.en.php

Hear is a calculator to get dimensions of an antenna for 1538MHZ.
Add a good LNA direct to the antenna.
The characteristic of the antenna is basically a sphere. So you get good reception without pointing the antenna anyware.
Best regards.

Benjamin Bergmann

Hello,

Very interesting posts and useful.

I’m also trying to make a link budget for a project of similar characteristics.
I was wondering which kind of antenna (model?) are you planning to use to have a Gar/Tsys of -15.94 ?

In most of antennas specs, the manufacturers usually only give the gain (Gar), and calculating the System noise temperature is pretty confusing (Tsys). I’ve seen many formulas and long technical explanations to calculate it.
But is there any simple way to calculate it? and have a good approximation for a first draft of a Link budget ?

Thanks!
Matthieu

Our antenna was basically designed through trial and error, so the T in G/T was never established.

So you just used a random value in the link budget ?

Just a guess of -16, based on some values seen on other receivers on the market.

1 Like