Can I attach 2 antennas?

Hello, I am putting an Xbee PRO 900 in a carbon fiber rocket and can not get the signal through. I have decided to put the antenna on the outside, but I am worried about an RF shadow created by the rocket. Can I use an RF splitter to make an antenna array so that at least one antenna is not on the opposite side of the rocket? The deadline for this project is approaching fast, and I need to know soon if this is a solution that will work.

When adding a splitter and antennas, you are just opening up a whole can of worms.

First, by splitting the line, you will only get 1/2 the Tx power to each antenna.

Second, if the cables aren’t the same length and the resistance is even slightly different (due to splices, bend, etc.) then you may get interference issues.

You could try a circular polarized patch antenna to help with signal issues.