![Why Is The Height Of A VHF Radio Antenna Important](https://techmediaarc.com/wp-content/uploads/2022/08/Why-Is-The-Height-Of-A-VHF-Radio-Antenna-Important.webp)
In the installation process of the VHF radio, the most important factor is to identify the location to mount its antenna.
Definitely, it should be mounted as high as you can. But placing it too high can also cause breakage in strong winds.
So, where do you exactly mount it and why is the height of a VHF radio antenna Important?
In general, the height of the VHF radio antenna is Important to Increase the signal strength and make communication easier between two radios.
But definitely, it’s not the only thing because of which the height of the antenna is Important.
So, let’s find out other major reasons in this post.
What is a VHF radio?
Before going behind the importance of antenna height, we must know about VHF radio and the Importance to have one.
VHF is an acronym for “Very High Frequency” and indicates the wavelength of signals emitted by VHF Radios.
As VHF signals have a longer wavelength and can travel far than UHF (ultra-high frequency) signals. That’s why VHF radios are an essential part of a boat’s security kit.
This same characteristic of VHF radios also makes them the most commonly used radios for other outdoor communications.
Such as for the communication between Grounds keeping crews, patrolling security guards, golf courses, boating, and camping groups.
Reason To Have VHF Radio:
The most common reason to must have a VHF radio is to get help when you face an emergency at sea.
Although VHF radios are not on the list of required tools, provided by federal boating regulations. But, still, boat insurance companies strongly recommend boaters carry a VHF radio and understand its functionality.
Another reason to keep VHF radio is to stay in touch with other boaters. So, that you can notify them about harmful conditions or can inquire about nearby communities onshore.
Also, you can find out where the nearest marina is located if you have a connection with captain fellows via VHF radio.
Why is the Height of a VHF Radio Antenna Important
As the two-way communication of a VHF radio is based on high-frequency signals propagated by the ionosphere.
And also VHF can’t follow the curve of Earth and cannot pass beyond the horizon. Hence, the large structures and hills can restrict the range of signals.
But the good thing is that ionosphere behaves like a mirror and uses an antenna for the reflection of signals. It’s also known as “line of sight” technology.
So the appropriate height of the VHF radio antenna is Important because the vertical angle of a signal defines the antenna’s communication distance.
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Another necessary thing is to have a low radiation angle for long-distance communication. And if an antenna will be set high it will follow both rules of signals propagation.
To understand it in a more easy way you take the example of light. As we all know that light travels in a straight line.
Any obstacle like Wall, Door in between two rooms can block the light to pass from one room to another.
VHF frequency range also follows this same principle. Hence ground mounted VHF radio antenna will not be able to pass or receive signals. So, Positioning the antenna higher will reduce barriers.
Also, when I say you should position the antenna high it doesn’t mean it should be too high. You can’t neglect different weather conditions and strong winds.
So, to determine the ideal position let’s
Calculating VHF Antenna Height For Better Range?
As we know that antenna height directly impacts the communication range of VHF radio because of line-of-sight communication.
So, it’s quite easy to calculate the expected signals range of VHF radio through the antenna’s height and the curves of the earth.
You can use this given below formula to find the range of VHF radio
d = 1.22 h
In this equation, “d” represents the expected range in statute miles, and “h” represents the height of antenna in feet.
This equation can be simplified to
d = h
Because in the sea we use nautical miles rather than normal miles. And one nautical mile is equivalent to 1.15 statute miles.
But, now in this equation “d” belongs to nautical miles, and “h” is antenna height in feet.
However, In this formula you only get the range for only one antenna. As, an example you can Imagine you are holding a handheld radio at sea level. Its height will be approximately 3 feet.
If you’ll calculate with above formula you’ll get a range of approximately 1.7M.
To know about exact range you also need to consider the height of receiver antenna. Keep it simple by adding two same ranges together.
Hence both antennas of 3 feet height will mutually allow you the 3.4M communication range.
For the communication range of the antenna of large ship we have another formula which is
d = 3 + 100
d 12 M
So, if a boat’s handheld antenna is 3ft (1m) above then we can assume the ship’s antenna will be 100ft (30m) high above the water.
And definitely, it will provide more communication range than a boat.
VHF Antenna Height: What Is The Ideal Value?
A VHF antenna should be mounted as high as possible to get the ideal range. The most common locations are the top of the mast and the roof of the cabin.
As per the result of the equation we’ve already seen that the antenna’s height directly affects the range of signals.
![Why Is The Height If A VHF Radio Antenna Important - Getting The Idea Value of Height](https://techmediaarc.com/wp-content/uploads/2022/08/Why-Is-The-Height-If-A-VHF-Radio-Antenna-Important-Getting-The-Idea-Value-of-Height.webp)
So, if you have a 20ft boat along with an 18ft mast you can expect communication over 5 miles.
Only if you mount the antenna on the top of the mast. You can’t expect the same range if you mount it on the cabin top.
Extending The VHF Antenna Range
You can minimize the interruptions to make signals clear and maximize the effectiveness of your VHF antenna by following the tips given below.
Raise the antenna
One of the most important factors for signal clarity is the antenna’s height. The antenna should be high enough so that no obstructions occur during the transmission of energy from the transmitter.
Radio Selection
Along with the quality of the antenna, it is equally important to have a good radio. So, make sure to select a radio that can produce great output. As wattage increases, the signals get more clarity.
Battery Selection
Make sure to use the recommended battery by the radio manufacturer. A standard 12 volts battery can generate more powerful signals. Less competent batteries can cause weak signals.
Set Up A Repeater
You can extend the range of the antenna using a repeater. As it takes in signals from the antenna and forwards them.
To get the most out of the repeater you must mount it at a high location. Otherwise, it won’t help.
Antenna Maintenance
A neat antenna is more effective in broadcasting radio waves. So, make sure to check it regularly and clean it when required to get maximum performance.
Select The Right Location
The location also directly affects the propagation. As I mentioned in previous points, place it high.
Also, the location should also be free of signal interference. Appliances, such as TV and Computer Impacts the transmission rate.
Keep Connections In Mind
The antenna connectors have a significant impact on signal transmission. That’s why ensure that the connecting points are insulated. Another benefit of doing this the antenna will also be more stable.
Install a strong base
Mounts have equal importance for the proper functioning of antennas as connectors do. It is essential to have a strong base for the environments where the wind is a factor. By doing so, you will be able to keep your antenna well-balanced even in the strong winds.
VHF Radio Antenna: Pro Tips For Buyers
Although antenna height is a significant consideration, this is not the only factor that clarifies the signals. You must also consider the quality of the antenna you select.
dB Rating
dB rating of any antenna represents the energy that it can produce. It’s not always better to have a higher rating.
Hence, a dB rating should be selected depending on the use.
![](https://techmediaarc.com/wp-content/uploads/2022/08/why-is-the-height-of-a-vhf-radio-antenna-important-Checking-the-dB.webp)
An example of a boat might help you to understand it better.
So, you can go for 3 dB for boats having a height of fewer than 24 feet. And 32 dB for the boats having a height of more than 32 feet.
Height
An antenna with a higher height is better. So, always go for the adjustable option while buying an antenna.
In this way, you can mount it as taller as possible and in return, you’ll be able to ignore all obstacles. Also, you can get a much longer range for your VHF radio.
Manufacturing
Build quality and material should be considered. As it directly Impacts the performance. Nylon ferrules are used in the production of cheap antennas, which is not a recommended option.
Antennas built with materials like fiberglass or stainless steel are much better. But, definitely, the durability also depends upon the brands.
VHF Range: Is Height More Important Than Power?
You may think that antenna height is the most crucial factor for the VHF communication range.
If you go behind the logic you might think that power is important for the transmission. The reason for going behind the logic is the “high power” and “low power” switch on your radio.
And this behavior is quite normal. But, in actuality, height is more important than power for range determination.
This is because even though the power of VHF is low but still it can travel long distances.
VHF Communications Are Line-Of-Sight Only. Why Is That?
In the electromagnetic spectrum, VHF radio Communication occurs at a frequency of 150 MHz.
As this range of frequency is very high, that’s why VHF signals don’t get any kind of refraction. Hence, they have to follow a straight line for traveling from one point to another.
Conclusion
So, now we know that the height of a VHF radio antenna is important for clarity and a better range of communication. The good height also reduces the obstacles that occur in its line-of-sight transmission.
Hope you’ve found this blog post very beneficial for you. If you like it do add your review in the comment section.
![Muhammad Talha](https://techmediaarc.com/wp-content/uploads/2022/08/Talha.jpg)
Being a radio enthusiast I know that it’s very difficult to get the information available on the internet for radio lovers. Also, sometimes it’s not satisfactory. That’s why I set up a website to share my helpful knowledge and best products with the amazing community of radio lovers.
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