Thanks Akash.

Does this handle only path loss ? Or do we write fading and shadowing also here?

Comment the function 

propagation_calculate_fadingloss(propagationHandle,

             packet->nTransmitterId,

             ifid,

             pstruEventDetails->nDeviceId,

             pstruEventDetails->nInterfaceId);

and write your own fading model

The shadowing model is built in with the pathloss model. So the way to modify this is to set NIL shadowing in the UI. And to code the shadow model after the fading model. 

In essence, the received power will first change because of fading power and then because of shadowing power. So the code would look something like -

dFadingPower = fn_my_fading_model();

dShadowPower = fn_my_shadow_model();

dReceivedPower -= dFadingPower+dShadowPower;

Thank you !

I have a follow on question. If I want to set my own receive power at a destination can I do this in some way? That is lets say I want a set of Rx powers like

1 -->2 = -75dB

2 -> 3 = -80 dB

3 -> 1 = -70 dB ... etc

This article has some useful information https://support.tetcos.com/support/solutions/articles/14000105921-how-to-see-the-impact-of-fading-in-a-netsim-wsn-simulation-