How to display a variable Receiver Antenna's Gain value onto the Spectrum Analyzer in Matlab Simulink?

Dear Sir,

i have a problem in displaying a variable's value , named Gr onto the Simulink's Spectrum Analyzer

This variable Gain's value (Gr) is to be passed onto the Receiver Antenna as its Antenna Gain value and i want to then display this Receiver Antenna's Gain value (Gr) onto the Spectrum Analyzer in the Simulink, but i don't know how to do that.

I have created a Model, Named: Testing_Receiver_Antenna_Only_V2 and is attached.

so please provide me with some suggestion/feedbacks on how to display the variable Receiver Antenna's Gain value onto the Spectrum Analyzer in Matlab Simulink.

Thanks and regards

Kei Lam