Hesperis;

If you're getting a lot of 'pops', you probably need to get one of those screens that you often see used in studios. They let the sound through but prevent the direct blast of air hitting the mic.

If you don't have that as an option, have you tried whistling directly over the reciever end of the mic, so that the air flow passes well over the mesh? At one show where we had to jury rig our sound set up I wound up with a REALLY sensitive mic on my spot. ANY noise I made was instantly transmitted over the PA... we managed to finally solve it by me singing over the top of the mic. They had to boost the level slightly, but it solved the air pops that I'd been getting...

M