10 -10 10 20 10 19 10 18 10 17 10 16 10 15 10 14 10 13 10 12 10 11 10 10 10 9 10 8 10 7 10 6 10 -9 10 -8 10 -7 10 -6 10 -5 10 -4 10 -3 10 -2 10 -1 1 10 100 1,000 10,000 100,000 Gamma ray  X-ray  Ultraviolet  Infrared  Radio UHF VHF HF MF LF VLF Wavelength (centimeters) Frequency (number of waves per second) Visible Shorter Higher Longer Lower Electronic Spectrum 11-31 Figure 11-74.  Radio waves are just some of the electromagnetic waves found in space.  Figure 11-73.  An audio panel in a general aviation aircraft integrates the selection of several radio-based communication and navigational  aids into a single control panel (left). A digital tuner (right) does the same on a business class aircraft and allows the frequency of each  device to be tuned from the same panel as well.  Figure 11-72.  A digital data display dedicated to the depiction of  engine and airframe system parameter status.  Radio Waves includes gamma rays, x-rays, ultraviolet rays, infrared waves,  and visible light rays, as well all radio waves.  [Figure 11-74] The atmosphere is filled with these waves. Each wave occurs at  a specific frequency and has a corresponding wavelength. The  relationship between frequency and wavelength is inversely  proportional. A high frequency wave has a short wave length  and a low frequency wave has a long wave length. In aviation, a variety of radio waves are used for  communication.  Figure 11-75  illustrates the radio spectrum  that includes the range of common aviation radio frequencies  and their applications. NOTE: A wide range of frequencies are used from low  frequency (LF) at 100 kHz (100,000 cycles per second) to  super high frequency (SHF) at nearly 10gHz (10,000,000,000  cycles per second). The Federal Communications Commission  (FCC) controls the assignment of frequency usage.  AC power of a particular frequency has a characteristic  length of conductor that is resonant at that frequency. This length is the wavelength of the frequency that can be seen on  an oscilloscope. Fractions of the wavelength also resonate,  especially half of a wavelength, which is the same as half of  the AC sign wave or cycle. A radio wave is invisible to the human eye. It is electromagnetic  in nature and part of the electronic spectrum of wave activity that 