Help needed with antenna gain settings

Basically, I just want to be able to create an antenna object for use in my txsite() and rxsite() functions for ray tracing, and I've seen so many functions and tried pretty much everything, but no luck so far in setting the gain to the value I want (7dBi). All I need is an antenna object that's of horn type, basic horn from the catalog, runs at 900MHz, and has a gain of 7dBi. I don't even care about its facing direction, because I can just rotate or do whatever with it once I set it as my transmitter and receiver. I can't seem to figure out anything that allows me to do so, there's a bunch of functions and properties that set everything else except the gain, then there's stuff I found like rfantenna() or Antenna Block object idk, that can allow me to set the gain, but not for a horn type of antenna. Is it impossible to do such a thing currently?

I have all the toolboxes downloaded btw, and RF and Antenna ones are no luck somehow.