Problem with 5V dips caused by walkie-talkies in transmit mode

If i use two walkie-talkie in transmit mode at the same time and see its impact on my pcb , i observe that my input supply 5V dips , why this is so?
and how to solve this [problem, because when i supply dips micro-controller gets reset for that time.

regards

It looks like RFI problem.

Try putting more bypass capacitors across your power lines. Spread them out.