"various frequencies" is correct English and can be used in written English.
An example sentence using the phrase would be: "The radio can be tuned to various frequencies to choose the best station."
The various frequencies extend beyond the chart - into the night.
The software algorithms then assign the various frequencies to the appropriate speakers for the desired result.
During the sound check the engineer identifies levels of various frequencies that will trigger feedback.
The Fleischer and Rumsfeld briefings, translated into Arabic, are now being broadcast into Iraq by American forces on various frequencies.
The behaviour under various frequencies and amplitude was explored.
(To make them pretty, his team took a bit of artistic license, substituting the familiar colors for various frequencies of X-rays).
Active sonar, at various frequencies, has been developed over the past two decades as diesel engines on military craft became quieter and harder to detect with passive sonar.
The dosimeter used A-weighting, which mimics the human ear's sensitivity to sound at various frequencies.
We systematically studied the design of symmetric and asymmetric PCs at various frequencies.
When various frequencies microwaves were input, the tunability resulted in a minor reflection coefficient of 0.05.
The current distribution and radiation patterns at various frequencies are plotted and indicate dual polarization.
