range for vhf icom m88

can anyone estimate a range for subject vhf marine handheld radio?


– Last Updated: Aug-17-07 11:43 PM EST –

The higher your antenna the more range. The higher the receiver antenna the more range. You will hear about great distances but I wouldn't rely on more than 3 or 4 miles.

Remember it's line of site. I once was trying to contact a boat, turned out it was 200 yds away but on the other side of a building and we couldn't hear each other. A third boat that was in both our line of site called us and told us what was happening.

The height and quality of the antenna on the station you’re talking to makes a huge difference. Kayak-to-kayak will have a much shorter range than talking to a large commercial vessel or a shore station.

It also depends on the power setting
You should be operating at 1 watt most of the time, but the radio is capable of 5 or 6 watts, I forget which. Don’t use the higher power unless you actually need it, as it’s the equivalent of yelling through your radio.

the Coast Guard on Maui advised us to use our cell phone rather than the VHF.

Line of sight
But remember, the Coast Guard has BIG antennas. I was suprised at some of my paddling spots that they could hear me. I could surely hear them and other vessels 10-20 miles away. The range will not differ much from one model to the next in the same conditions and wattage.

Here’s a great marine radio buying guide
… from Cabela’s:


Quote: “Under average conditions, with a 25 watt radio and an 8-foot antenna, you should be able to communicate within a 12 to 15 mile radius.”

Add to this the roughly 3-6 feet of actual boat height, and the antenna on a typical power boat might be 10-15 above the water.

Kayakers, by contrast, have 8-INCH antennas, no more than 5-6 watts of transmitting power, and often sit at or BELOW the wave height! I agree that 3 to 4 miles is a more realistic assumption. On a good day …

From Cabela’s:

"VHF Radio Buyer’s Guide

Marine band VHF (Very High Frequency) radios are one of those items that aren’t really appreciated unless there is a crisis. Most guys don’t even want to be contacted when they are on the water fishing or otherwise just enjoying the day. In fact, it’s one of those marine items that many people have a hard time convincing themselves that they really need to spend money on.

Author: Frank Ross

All of that goes out the window once water starts rising over your ankles. There’s something about taking on water, or having a battery go dead as a storm begins to build into a whitecap encrusted crescendo that makes one realize that the ability to key a mike and get help is a good thing, a very good thing.

For most anglers and pleasure boaters contemplating the purchase of a marine radio, the question is what model, features and power do I really need? Unfortunately, that answer can only determined after a crisis has presented itself.

The nature of the beast

VHF radios are very effective under certain conditions, and challenged under others, but the most predominate limiter is something that is insurmountable - the curvature of the earth. VHF is basically a line-of-sight signal situation. Lower frequency signals have an inherent ability to bend with the curvature of the earth, but not VHF. Once you get over the horizon, your ability to transmit and receive becomes diminished. The further you travel away from the receiving radio, the more your signal is deprecated until you reach a point where all you can hear is static. Regardless of the amount of power you have in a box, once you exceed the point where your antenna will not top the curve your only option is to reach another craft and ask for a relay.

The all important antenna

Because of this factor, one of the most important radio decisions you’ll make is the height of the antenna you select. This is one area where people with sailboats have a definite advantage. Most enthusiasts of the canvas kicker put their antenna on the top of their main mast, which gives them a dramatic increase in their electronic reach. Within reason, you’ll want to get the tallest antenna your craft and budget will support.

Once on the water, it really doesn’t matter how much power you have in the radio, if your antenna is lowered down and tethered to the deck. During most fishing situations, an antenna is just an inconvenience, and it’s fine to leave it down until you need to use the radio. At that time, you want to take the old west approach and “reach for the sky partner.”

Under average conditions, with a 25 watt radio and an 8-foot antenna, you should be able to communicate within a 12 to 15 mile radius. Weather, like violent electric storms, will always play a role in limiting that distance.

Digital Selective Calling Radios (DSC)

The latest and most dramatic change in marine radio technology is the requirement of DSC capability, mandated by the FCC. DSC is the system that was implemented to provide instant distress notification with an accompanying GPS location. While the mandate was first required of maritime ships, today all marine radios are required to have this feature. Offshore anglers are mainly concerned with this technology, but anyone who has ever been on one of the Great Lakes, or a large western reservoir will appreciate having the security that DSC provides.

Since 1996, recreational boaters are no longer required to have a ship’s station license issued by the FCC to operate a VHF radio; however, in order to gain the full advantage of the DSC capability you need to register your radio. Like cell phones, radios are encoded with a nine digit FCC identification number known as a Maritime Mobile Service Identity or MMSI number that allows you to take advantage of the ship-to-ship calling feature.

With this number registered with the FCC, DSC can send an automatic “mayday” that identifies the vessel and also, when connected to a LORAN or GPS, your exact coordinates are included. This one-button, goof-proof emergency signal transmission will continue even if the vessel operator is incapacitated.

Commercial ships over 300 tons are now required to monitor the DSC radio reserved channel 70, for distress calls. The US Coast Guard is still monitoring channel 16, but are scheduled to upgrade their equipment to be fully complaint for monitoring channel 70 by 2006. Until that time, the Coast Guard will not be monitoring these signals and you’ll be dependent upon other DSC compliant craft in the broadcast area to receive and relay your distress call.

Existing bargains

The government doesn’t require recreational vessels to have DSC capability. The onus is on the manufacturers to build it into new radios, and gradually the nation’s pleasure craft will come into the arena as old radios are replaced.

Radios manufactured prior to the DSC requirement are a real bargain right now, as they are slowly sold out of inventory. They are still legal to use, and the only disadvantage would be the lack of DSC technology. If you are an inland angler whose main use of a marine radio is listening to the NOAA weather broadcasts, these units are an excellent value while they’re still available.

Handheld units

Handheld radios have less power, but not necessarily fewer features. Some of the higher end models now incorporate GPS WAAS capability with the ability to send a user’s exact location to another unit of similar capabilities. Additional features like large data displays with chart-plotting maps, compatible with Magellan Blue Nav charting software and MapSend Street and Destination CD functionality are also available.

Power and reach have always been an issue for handheld units. Models vary from 1/2- to 5-watts of power, they are mainly utilized in an inland water environment, but when you balance the convenience and portability of these units in an inland or short distance situation offshore, they’re ideal alternatives for marine communications. Certainly, handheld radios have always been a perfect option for boaters who don’t have room or a place to put a larger bracket-mounted unit.

Today’s models have two levels of weather and accidental dipping protection. The most basic unit is JIS4 waterproof compliant, which means splash resistant. More sophisticated units fall into the submersible category or J1S-7 compliant. In order to qualify, radios with this designation must be able to withstand being lowered into a tank of water three feet deep for 30 minutes.

Maximum power

The advantages of the larger console or under dash models are numerous, but the most notable is power. These fixed location radios have a selector switch which alternates between 1- to 25-watts of power, which is an obvious advantage over the lower power of handheld units. With the advantage of larger bodies, additional features are easily added without the concern of weight or size.

From entry-level units to top of the line models, you’ll find similar features at each price point, with the one exception of Uniden. To address the difficulty of being tethered to your radio by a mike cord, consider the innovative remote microphone or WHAM. With the Wireless Handheld Access Microphone, you can utilize your Uniden® VHF radios from anywhere in the boat. You can be in the back of your craft, working trolling rods and respond to a radio call without running for the mike. The WHAM fits in a pocket, or clips to your clothing for easy access.

Another feature that is worth considering is their Triple Watch Plus™ channel monitor. Having to change from the channel you monitor for your fishing or boating partner to check the weather channel has always been a pain. With Triple Watch Plus™ you can monitor emergency channel 16 and 9, along with memory scan, weather scan and weather alert. During a NOAA weather or emergency alert, a code for your specific location will warn you about severe conditions in your immediate area.

One advantageous feature of individual models is the on-mike 16/9 button that gives you the ability to key the mike and send a distress message instantly, without having to fumble with the channel knob. In a crisis, when panic tends to take over, this is a definite safety advantage. Another mike feature, for the more advanced units, is the ability to control the radio from the mike, and some brands feature a mike/speaker which puts the sound closer to your ear in bad weather or high wind.

Other features, like a public address option and jack for an external speaker may have some interest to you, for hailing a passing craft or communicating with those waiting on the dock, but it also improves the sound quality over the standard small internal radio speaker.

Features like backlit buttons and LCD screens with multiple levels of brightness are nice options, but don’t have a lot to do with the basic reason for having a radio. If you do a lot of fishing or cruising at night, then the brightness of your LCD and having backlit buttons that are easier to find are an important feature. Look for options that meet your specific needs and don’t buy something you don’t need or won’t use.

Bottom line - if you think your boat is headed for the bottom, you want help and in a hurry. VHF radios have always been one of the best ways to get that help, and with the new DSC system your chances of getting it quickly makes the addition of a marine radio a wise investment.