Tiny Whoop Furibee receiver antenna

[DS123]

I've managed to snap off the small antenna from my Furibee whoop flight controller. I'm thinking of just trying to solder on some copper wire (on its way from China). But thought I'd ask on here if anyone has any better ideas and some clever person might be able to tell me what length it needs to be. Grateful for any comments.

[Coyote]

31.25mm length will be about right for 2.4GHz