Since a VHF antenna is line-of-sight communication technology, you can only communicate between two stations that are within sight of each other. Therefore, the height of a VHF radio antenna is important because it affects your communication distance.
If you have ever tried to talk with someone on an old CB or ham radio that has no external antenna attached, then you quickly realize that having a lower quality VHF radio does not allow for long-distance communication. A more powerful and higher quality antenna is necessary for better long-range communication on frequencies from 108 MHz up to as high as 450 MHz (a total of about 300 MHz).
To answer this question concisely, one must understand the concept of RF (radio frequency) waves. For a VHF radio station, RF waves travel in a straight line. This means that the shortest path between transmitter and receiver is no obstruction. In this case, as long as you can see each other your antenna does not need to be as high because the curvature of the Earth limits how far two objects can be from one another given their height above sea level.
The higher both antennas are, however, the further you can communicate so if there is an obstruction or terrain positioning may play a role in whether a taller antenna would be preferable.
You should also consider going with a better quality VHF radio simply because it will have better audio clarity and therefore allow for easier communication. The components inside a VHF radio directly affect audio quality which is why it is important to pay attention to VHF radio reviews and the components used in the radio when looking for your next setup.
Notably, since a VHF radio antenna is line-of-sight communication technology, anyone trying to communicate with you must be able to see your station for reliable long-range communication. If there are any obstructions between you and another station, then the range decreases considerably based on the height of each station’s antenna.
Also, certain frequencies can provide long-distance communications because they either travel further or do not get absorbed by atmospheric gases as much which allows them to travel further. These frequencies are typically higher than those that come from an FM radio station broadcasting at about 88 MHz (the lower end of the VHF spectrum)
In addition to being a line-of-sight communication technology, VHF radio signals are also more susceptible to atmospheric absorption. This means that the longer a VHF signal has to travel through the atmosphere, the more it will be absorbed as it goes along. The lower frequencies have greater distances of travel and therefore less resistance whereas higher frequencies have shorter distances of travel and increased resistance.
In this case, the frequency may play a role in determining optimal antenna height for your specific needs so you should do some research on different VHF frequency bands if you need to communicate over a long distance.
One thing remains true: larger antennas typically allow for stronger transmissions that relate directly to better audio quality from your speaker or headset output. Larger antennas typically also have a broad range of frequencies that they can cover which means you will get better reception on both strong and weak signals.
In addition to all of this, there are other components in your VHF radio setup that directly affect the audio quality such as noise filtering and microphone gain. They play important roles in ensuring reliable long-range communication so it is best to consult with a knowledgeable communications expert or VHF radio review before making your purchase.