Instructions
Visit the location where you plan to use your radio-controlled device the most. Take note of the frequencies being used in that area. If the area is run by an organized club, ask for a list of registered frequencies used by the club.
Find an open range of three frequencies. As an example, you may notice that 24MHz, 25 MHz and 26MHz aren't being used within your club. If you can't locate three unused frequencies, you may be limited to setting a band guard between your frequency and one other frequency. For example, your list may indicate that 24 MHz and 25 MHz are open but 26 MHz is used.
Select a band that has an open frequency on either side if possible. For the earlier example, select the radio frequency 25 MHz. If a single guard band is all that's available, you must make due. If possible, operate your device when the adjoining band isn't in use.