i am going to record a band in a football stadium. i wil use the built in mic on the XL2 but i also think about placing a microphone on a stand on the grass and record this using a sennheiser wireless setup

what microphone would be good to use and what other things should i be aware of (wind, ...) and what to do about them.

i do have an AT-RE50B not sure if that would do the trick

thanks

no takers ?

I think you mean an EV (electro-voice) -RE50B?
Never worked with it, it's an omni directional mic, so it won't be rejecting sound from any direction, but will give you a fatter bottom end than a cardiod will.
You'll have a tough time syncing the on-cam and omni directional if they're very far apart on a football field.
Is the band marching? Or in the stands? In the stands, this is easy. I'd not use the on-cam mic, but attempt to find another RE50B, and set them up as far apart as the band is wide, or set them up in an XY configuration.
Marching is another story.

Based on what the folks here helped me with, I use a A-T 835ST. Quick and dirty, I mount it on the cam. If I go for quality audio, on a 5' stand a DCI venues and on a mast at the 50 at venues I can control some of the setup. That is for field setup.

If you shoot high during a football game's halftime, you need a shotgun (the 835ST is) to 'reach' over the crowd some. If it is a band competition (and you are allowed to shoot), the crowd is quiet, but you still want to reject as much side noise.

Wireless was risky as you need a pair to do stereo and there are all sorts of radios at football games.

Otherwise, you can go crazy. DCI used 4 mics front, 2-3 for crowd ambiance, and I think there was 1 on the back field (they do 5.1) You will need someone to set it up and monitor it while you do video ;)