when i first got my P4 i wanted to see what it had being straight out of the box, i was able to push it to 19,000 ft (stock)and was scared to go further, as i was getting the weak transmission signal at that point. So did a little research and came across the DBS ITE LITE panel from Jake at MaxxUAV.com..nice guy to talk to ...so i purchased the DBS panel, set of those black screw ones for shorter trips, and the clean install kit....wanted stronger signal, and could not be happier