You might do better just to buy a microphone designed for paging systems. I know Shure makes a variety of them, from desktop stand ones (like what your high school principal had) to gooseneck mounted, like you see at some restaurants. I would try searching eBay...I bought a Shure 550L paging mic for $10. Another bonus is that a lot of them come with an extra pair of wires tied to the switch that you can use to trigger a relay, which can have a number of uses. When I get the time I plan on wiring mine to my console's Talkback-to-Cue switch, so that simply pushing the mic's talk button enables the talkback function on my console.