No you will no screw anything up, or damage the radio, you are just detuning it. This result is degraded performance. By cutting it 6" you are changing the antenna's tuned range to a higher frequency (higher than the 108Mhz upper limit of your radio). The shorter the antenna the higher the frequency its tuned for (I have the formula for antenna tuning if you need it.) Antenna length is much more critical in transmitters than receivers. Basically, It will still work, just not as well. Hope that helps, Mark