This will get the little buggers close enough to me for a decent bow shot..
I bought a 50 watt megaphone, cracked open the microphone and installed a 1/8 jack to override the Mic when being used as a caller. Slipped up to Wall Mart and picked up a cheap 1gig MP3 player and plugged it in, voilĂ*! I found a few calls in MP3 format to download and the thing is very loud!
I need to butcher my camo pack to carry this thing but I just saved a pile of money.. Not much else to hunt around here right now, so this should help even the odds.