channelWidth property value indicates the channel width of the ranges of frequency, in MHz.
Usually, the value is one of:
0.1 (default) or
When a frequency is assigned to the radio, it is rounded to the closest frequency given the
channelWidth. For example, if 100Mz is a valid frequency and the channelWidth is 0.2, 100.2, 99.8 are also valid frequencies, but 100.15 will be rounded to 100.2.
var width = instanceOfFMRadio.channelWidth
Return a boolean.
Not part of any specification.