Futaba 3PM 2.4G receiver antenna length

[vashon10]

I have purchased online a Futaba 3PM 2.4G system based on the good reviews. I've never actually seen it in person, but my question is about receiver antenna length. It is apparently 210mm long (futaba tells me), yet I see stubby short antennas in trucks using 3PM receivers, they don't even extend out of the body.

I'm confused, since I thought all 2.4G systems usually had very short receiver antennas. Have people shortened the 3PM antennas ?