let me ask a dumb question. the crystals frequency are catorgized by channels ? if so why not just go by the frequency. so anynegative<span class="Apple-style-span" style="font-family: Verdana, Arial; font-size: 13px; -webkit-border-horizontal-spacing: 1px; -webkit-border-vertical-spacing: 1px; ">modulation shift reciever should work as long as it has the same frequency crystal. but why cant you change the crystal in the transmitter</span>