How Far Will a Handheld Marine Radio Transmit?

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You’ve taken your first step towards becoming a boater. Whether it is buying, borrowing, or renting a boat, it has opened a new world of excitement for you. Now before you take on unchartered waters, you need to purchase a marine radio.

You have completed your first marine radio test, and now you are wondering just how far this handheld device can transmit. It is the most googled question regarding marine radios, so if you were wondering about this, you’re not the only one.

What is a VHF Marine Radio?

A VHF marine radio is a radio that runs on a very high frequency of 156.000 MHz to 162.025 MHz. This is called the VHF Maritime Mobile Band by the International Telecommunications Union, also known as the ITU. All marine radios are built to run on a pair of frequencies between this mobile band.

Frequency pairs that match are then stored in the radios as channels. This process saves the operator the duty of searching for frequencies as the channels allow for quick and accurate tuning of the frequencies.

Due to their popular demand, VHF radios have developed a great deal over the past few years. A VHF radio two decades ago will appear a lot different from one made today, as great features such as DSC have been added. VHF radios of today can also interface with several other electronic systems such as GPS and AIS. There are rumors of data transmission coming our way in VHF marine radios in the future. What an exciting time for boating!

Related: Best VHF Marine Radio for the Money

How Far Can My Handheld Marine Radio Transmit?

As mentioned above, this is a question that has been asked often and continuously. It is, however, a question without a definite answer. Many factors come into play while using your handheld marine radio that could easily influence the transition range of your handheld device.

The one thing that we can be sure of, though, is that a handheld marine radio offers a relatively short range. The exact shortness of the range depends on many factors. By far, the element that is the most limiting is the fact that these handheld radios only operate on a line-of-site premise.

This means that both the receiving and transmitting antennae must view each other to send and receive transmissions properly. Another three factors also have an impact on the range offered by a handheld VHF marine radio.

deck officer using radio on the board of a tanker

1. Antenna Height

When you start to look into marine radio communication, antenna height is the most critical factor to keep in mind. The reason for this is that the higher your antenna is placed, the further you will be able to communicate. When you are in open waters, and you have an urgent need to communicate, every little bit helps, and being able to communicate further is of great importance.

If offered a choice between antennae, choose one that will give you a higher reach. Another thing that needs to be kept in mind when selecting the correct antenna for your handheld device is that your antenna will need to be placed perfectly vertical. This is called vertical polarization, meaning that your antenna will perform at its best if it is mounted perfectly vertical. Antennae placed at angles will not be able to offer the best range.

2. Obstructing Geographical Elements

Unfortunately, a handheld VHF marine radio won’t transmit or receive a message if there are typographical features in its way. As mentioned above, these devices only operate on a line-of-sight function. If something is blocking the view of the other antennae, the message won’t be received or transmitted. Simply put, any intervening obstructions that come between the two communicating devices’ antennae will result in failed transmission.

3. The Power of the Transmitter

Handheld marine radios offer a transmission power of 25 watts at most. Short-range communications can be completed with a power range of as little as 1 watt by a particular operator switch. Newer models can automatically switch the transition power to 1 watt when you are communicating at a short range. Although it isn’t an obligation to switch to 1 watt when communicating on a short range, it is seen as a common courtesy.

Why should you switch to a lower transmission power when communicating at a short range? Well, think about it this way. Let’s say your handheld device has a range of 15 nautical miles (27km). That is a large radius around you that can now not be used by any other frequencies. The best rule of thumb is low range, low transmission power.

However, for long-range communications, the principle is that the more power you can transmit combined with the height of your antenna, the further your transmission will reach. A lower antenna combined with low transmission power will result in a very short range.

It Seems Like The Question Still Remains

We are still left wondering just how far our handheld devices can transmit. Although it is evident due to the reasons given above that many factors can influence our range, we must be able to have a broad idea. On average, experienced boaters who use handheld VHF marine radios have a transmission range of about 10 nautical miles (18km).

Boaters have shared experiences of communicating with other boaters at a distance of 18 nautical miles (33km). That being said, the conditions on the day were perfect. The most important thing to remember is, the higher you can place your antenna, the more extensive your range will be.

Final Thoughts

As with life, boating has many factors we can’t control. But how far will a handheld marine radio transmit? Well, some areas remain uncertain, including the fact that we can’t state the exact number of how far your handheld VHF marine radio can transmit.

What we do know, though, is that these devices offer a valuable and necessary service to us while we are in the water. Our marine technology keeps developing and improving, and that is because of the loyal boaters who dedicate their lives to improving our love of open waters.

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