pre-game positioning: MIDDLE of the pyramid?

You can have an antenna as long as it fits within your frame perimeter.

I also fail to see what this would achieve. If you were to start behind the alliance line with 3 frisbees, you wouldn't be getting in your partner's way (assuming they start in front of the pyramid), and an antenna wouldn't assist you in any way, as it would just move your robot farther back from the tower and closer to the center line.