I've just spent a couple of days reworking one of my satellite calculator pages:
https://www.satsig.net/noise.htm
by adding a calculator so you can work out the expected G/T of a receive antenna. Input things like the antenna gain, antenna noise temperature, waveguide loss, LNB temperature, cable loss, modem Noise Factor NF etc.

I need help testing it.

If anyone is interested please try it out and tell me if any results do not make sense.

Best regards, Eric.