There are many TV signals detected in the data. These stations are located both inside and outside the NRQZ. The strength of these signals can change from day to day, or even throughout the day from morning to evening. The three vertical white bars are signals from the strongest Digital Terrestrial Television (DTT/DTV) channels outside the Quiet Zone. These stations are thought to be outside the Quiet Zone because they broadcast powerful signals in all directions. The stations within the Quiet Zone usually have limits on how much power they can send the GBO. You will notice that these three signals are the same width. That is because the Federal Communications Commission (FCC) assigns (or allocates) 6 MHz to each DTT station. They are expected to stay within this range, and they could face fines if they broadcast outside of it. These signals are found between 470 and 608 MHz and can be seen in the red rectangle.