What radio frequency travels the farthest

In general, yes, higher frequencies attenuate more the further distance they travel . There are two effects that are responsible for this. First, higher frequency radio waves tend to be absorbed more readily by objects (ie: the penetration depth in the material is shorter).

Because low frequency sounds travel farther than high frequency ones , infrasound is ideal for communicating over long distances. This figure illustrates the concepts of frequency and amplitude. The magenta wave has one half the amplitude of the black wave, and produces a quieter sound.

Because both are simply EM waves. They differ only in rate of information sent. Due to the penetration power of high frequency radio waves in general, is the major limitation of FM staions where the AM uses ionosphere for reflection and hence it covers more distance .7 Şub 2008

In general, low frequency waves travel further than high frequency waves because there is less energy transferred to the medium . Hence the use of low frequencies for fog horns. Although damped waves have decreasing amplitudes, their wavelength and period are unaffected.