Features July 15, 2005 Issue

Best Fixed-Mount VHF: Icom M302

With better basic audio and transceiver performance, the Icom M302 surpasses more full-featured competitors in our test of units under $160. Standard Horizon's Quest is a close runner-up, and Raymarine's Ray 48 comes up short.

The Icom 502, shown here, is the larger sibling of the M302, which prevailed in our tests.

VHF marine radios remain the most common and useful communication devices found aboard recreational boats. And for good reasons: They are inexpensive, have no monthly user fees, and can be used for routine voice traffic as well as emergency calls. Plus, with the advent of Digital Selective Calling (DSC) several years ago (see sidebar), limited digital information can now be sent via VHF. Other methods of communicating by voice, via cellular phone, for example, have become popular and do have a place on a boat—just not as the primary communication tool.

A cellular phone offers one-on-one communication through a connection that's often poor, while a "Mayday" on Channel 16 goes out to everyone within line of sight. Smart cruisers always have a working VHF aboard their vessel.

The electronic circuits in today's marine VHF radio transmitters and receivers have remained virtually the same for years. But the implementation of DSC—a required function in any VHF radio designed since 1999—has altered the landscape recently in the VHF marketplace. Today, even the least expensive VHF radios can have an extensive list of DSC capabilities.

As we'll see in this review of radios less than $160, the quality of the transmitters and receivers varies, as does the level of DSC commitment. Some makers continue to market older designs that lack any DSC capability, while others sell recently designed radios with extensive DSC capabilities.

What We Tested
We rounded up six fixed-mount marine VHF radios that fit our under-$160 price category. All but one was within $10 of the price limitation. Icom supplied us with its M302, Raymarine sent the Ray48, and Standard Horizon loaned us the Quest GX1255S. Uniden builds the three others. It markets two under the names Solara (the least expensive tested at $120) and Oceanus. And West Marine's 500 VHF is also a Uniden-built radio.

How We Tested
Each radio was run through a series of bench tests using a Ramsey COM3010 communications service monitor. This highly sophisticated piece of equipment verifies transmitter power output, frequency accuracy and stability, and receiver sensitivity.

Marine VHF transmitter power output is limited by FCC regulation to a maximum of 25 watts. A low-power setting for harbor use, typically 1 watt, is also required. These numbers can be translated into the amount of radio frequency (RF) energy coming out of the back of the radio. Numerous other factors might further limit the actual power output at the antenna. All of our measurements were taken directly off the radio antenna port of each unit.

Frequency accuracy is the ability of the transmitter to send signals out on the correct frequency. Frequency stability measures the transmitter's ability to maintain frequency accuracy over its entire temperature operating range. Regulations mandate an accuracy of 10 parts per million while industry groups typically call for half that error. This equates to being about 1550 Hz off frequency on marine-band radios.

Each transmitter test was done on channel 16 at room temperature (74° F), as well as temperature extremes near the maximum ranges of each radio.

To reach the cold extreme, each radio was put in our freezer (at 15° F) for four hours prior to testing. We used a fish smoker as an environmental chamber to get the radios to high-temperature extremes. Each was left to cook for two hours at 122° F and then immediately run through another transmitter power and frequency test.

We also tested at two input voltages. First, we used a CSI Speco 50-amp power supply to produce 13.8 volts DC to simulate operations in a boat with the engine running and the alternator powering the boat's electrical system. Next, we stepped down the voltage to 11 volts DC to simulate trying to transmit with a nearly dead battery. Amperage-draw measurements were recorded using a Fluke 336 clamp-on ammeter when transmitting at both 13.8 and 11.0 volts DC. We also checked each unit's low-power setting, measuring both power input and output. Power output for each test is shown in the accompanying chart. Frequency stability was rated over the entire range of transmitter testing; the closer a unit held to the appropriate frequency, the higher it was rated.

Receiver sensitivity is the ability of the receiver to hear a weak signal. This measurement is taken in microvolts. Typically, marine VHF receiver sensitivity specs run from .22 to .35 microvolts, with industry groups recommending a minimum of 0.50 microvolts. Each radio receiver was tested for sensitivity, the minimum signal it could receive at a specific industry standard ratio between background noise and generated signal. All the radios rated Good or better, meaning they are sensitive and more than capable of picking up very weak incoming signals.

Another receiver standard is selectivity; it is the ability of the receiver to reproduce only the signals you want to hear and not others, even though they may be strong and nearby. Our equipment did not allow us to test each radio for this characteristic. Information listed in the table under selectivity is provided by the manufacturer. A higher number is better.

The display on each radio was rated by our tester based on the size of the channel number display, the amount of other information shown, the size of the screen, and the quality of the backlighting.

One important part of the radio often overlooked is the audio amplifier and speaker. If you can't hear the output, it doesn’t matter how well the transmitter or receiver work. To rate the audio system of each radio, we measured the sound pressure at maximum volume while generating a 1-KHz tone with our COM3010 and inputting the tone into the radio. Measurements were taken at a distance of 1 meter using a Radio Shack decibel meter. Our tester also rated each audio system with a voice input by monitoring a weather channel and rating the quality of sound reproduction.

All the VHF radios we tested here have a basic set of features that includes display and use of all International and U.S. voice channels, the 10 designated weather channels, and the ability to scan all channels. All control audio volume and squelch with knobs, channel changing with up/down pushbuttons, and all carry a 3-year warranty. Anything beyond these basics is considered a "value-added feature" and was given a rating. Units with more sophisticated DSC capabilities, superior channel comments (channel usage descriptions on the radio display), and other features, like time and position display, received higher ratings.

Icom M302
Exceptional performance has been the hallmark of Icom radios for years, and the M302 holds up that standard. It had superior results in our performance testing. Transmitter output power and frequency varied little over the full sequence of tests. A quick look at the input power measurements indicates the Icom has the most efficient transmitter tested. In addition to an Excellent rating for receive sensitivity, the Icom ranks with the best in selectivity. And audio output ranked this radio at the top, too.

Additional features found on the M302 include the full list of DSC capabilities discussed in the accompanying sidebar ("Digital Selective Calling Update"), channel comments (which tell the user what the channel is used for) displayed in a five-character rolling display, and the ability to utilize all Canadian channels. Selecting channel 16 or 9 is accomplished with a pushbutton on the radio face; this button can also be reprogrammed to quick call another channel in place of channel 9. Channel comments can be reprogrammed to user comments as well.

The M302 can listen for signals on channel 16 while monitoring other channels via Dualwatch and Tri-watch. Scanning several channels at once is accomplished via normal or priority scanning. Normal looks at each channel in order, while priority checks channel 16 between other channels. To further enhance scanning, channels can be "tagged." Channels not tagged will be omitted from the scan.

We rated the display on the Icom Excellent even though it's a bit smaller than the Standard Horizon and lacks the large number of character symbols found on the Uniden Oceanus. It does have the best backlighting, with 3 levels of adjustment, the ability to display Alpha channels when selected, and both transmit and receive icons.

Additionally, Icom claims that this unit is submersible to 1 meter for 30 seconds. We didn't test the waterproof claims on any of these units, but we did note whether or not the manufacturer claimed the unit was waterproof.

Bottom Line: Excellent transmitter, receiver, and audio performance coupled with full DSC capabilities, and a significant list of features makes the Icom M302 our top pick.

Ray48
Transmitter power output varied widely during testing at temperature and voltage extremes. It produced the lowest wattage output of any radio (15.7 watts) in the low-voltage test. On the upside, frequency stability was rated Good over the entire range of transmitter tests. The receiver was rated Good for sensitivity but lacks a bit of selectivity. It ranked at the low end of the radios tested with a specification of greater than 65 dB. Audio output was rated Good with the highest recorded sound pressure levels in this group.

Quick selecting channel 16 can be done with a pushbutton on the radio face or a button located on the microphone. Scanning can be either all-channel or channels recorded in memory. To memorize a channel, first select it, and then hold the scan button for two seconds. A momentary press of the Scan pushbutton turns scanning on or off.

The list of features in the Ray48 is short and we gave it a Poor rating for value- added features in the table. It has no DSC capabilities, lacks a Canadian channel designation, and has only rudimentary scanning capabilities.

The Raymarine display screen was rated Fair. It has large block numbers to display the channel selected, but backlighting is not adjustable and it shows no channel comments.

Raymarine markets the Ray 48 as "fully submersible."

Bottom Line: This radio ranked only mediocre in performance and lacks many of the features found on other similarly priced sets.

Standard Horizon Quest
The Standard Horizon Quest ranked second only to the Icom in overall transceiver and audio performance. Transmitter output was above average in power and stable over the full range of temperatures and voltages tested. Frequency stability was rated Good, missing a higher rating by a few Hertz. Receive sensitivity was rated Excellent while selectivity specifications are comparable to the Icom at 70 dB. In audio testing the Quest managed a sound level of 90 dB and was rated Excellent in audio quality.

It has a long list of features, including the ability to input GPS data, display lat/lon information, and current time with an offset adjustment option. Channel comments are displayed with seven character symbols, and user changes are possible. Information shown in character symbols longer than seven characters will automatically scroll. A 16/9 pushbutton on both the radio face and the microphone selects these channels with a momentary push.

DSC capabilities include the ability to send and receive distress, individual, and all-ships calls with priority messaging. Geographical, distress relay, and position request calls can be received. The radio's directory will store up to 20 individual MMSI numbers with a 12-character name attached. This is where you'd store all your friend's numbers for discrete calling via DSC.

Channel scanning can be done via Dual watch, Triple watch, memory scan, or priority scan. Any channel can be designated as a memory channel.

We rated the Standard's display screen Excellent; it is one of the largest, has easy-to-see, block-style channel numbers, adjustable backlighting and contrast, displays Alpha channel information, and has both transmit and receive icons.

This radio is described as "submersible," by the manufacturer.

Bottom Line: Good transceiver and audio performance in conjunction with a long list of features makes the Standard Horizon Quest our runner-up.

Uniden Solara
The Solara was less expensive than the rest of the field. Although transmitter power output was fairly stable throughout the range of tests, frequency accuracy was off at certain voltage and temperature extremes, causing us to rate the transmitter frequency stability Fair. Receiver performance was a bit better, and the Solara garnered an Excellent sensitivity rating. The selectivity specification was only 67 dB. Audio performance was mediocre.

We are impressed with the fact that even though the Solara is the cheapest radio we tested, it still has rudimentary DSC capabilities. It can make a DSC distress call (including sending position information if connected to a GPS), an individual call, and an all-ships call using priority messaging. Scanning on the Solara is limited to all-channel scanning. We rated this unit Fair for value-added features.

The display window in the Solara is the smallest in our field. Channel numbers are shown on the right side of the screen and no channel comments are displayed. Backlighting is factory set to one level.

The Uniden Solara is described by the company as having a "weather resistant housing, microphone, and microphone connection," and retailers claim it will function after being immersed in 1 meter of water for 30 minutes.

Bottom Line: The least expensive radio we tested, this unit was only an average performer and has a limited list of features.

Uniden Oceanus and West Marine 500
These radios are nearly identical, with only slight cosmetic differences readily apparent. Overall performance was very similar between the two as well, and just a step below the best radios in our test. Transmitter results were comparable and generally good. The Oceanus fell a bit short in power output during the low-voltage test, while the West Marine slipped off frequency just enough to get a Good rating for stability.

Both receivers managed an Excellent rating for sensitivity, but rank below the best radios in selectivity specifications. The Oceanus is rated 65 dB while the West carries a 67 dB rating. Audio output hit just 88 dBA on both, while audio quality was rated Excellent.

Recently designed and new to the marketplace, these radios have features not seen before on radios in this price range. Both the Oceanus and West 500 boast a public address system, time display (needs GPS input) with an alarm clock, local time adjustment, and daylight savings time adjustment. Other new features include the ability to use and input NWS FIPS codes (they allow geographical weather alert selection), and the ability to use a wireless handheld access microphone. In addition to all the DSC capabilities, these radios have the ability to store DSC group MMSI numbers that allow for outgoing group calls in a separate directory. Each radio's individual MMSI directory can store numbers for 20 other vessels.

Triple watch scanning of channel 16, 9, and any other voice or weather channel can be accomplished by pressing and holding for more than 2 seconds the 16/9/Tri key. Momentary hits of this key select channel 16 or 9. Memory scan is also available.

Displays on both radios were rated Excellent. They have 12-character symbols to display channel comments, a transmit and weather alert mode icon, and 3 levels of backlighting and numerous contrast levels. One thing missing is Alpha channel display.

The Uniden Oceanus carries a 3-year waterproof protection warranty; the West Marine 500 is listed as "waterproof."

Bottom Line: Impressive new designs with a myriad of features, but basic transceiver and audio are a step behind the best models that PS tested.

Conclusions
We think DSC provides significant added value to a VHF radio today and will prove even more valuable in the future. However, the primary function of a marine VHF radio is to communicate by voice with other VHF-equipped vessels. Therefore, our primary emphasis when selecting a radio remains here. The best overall performer in our review was the Icom M302. It beat all others in basic transmitter, receiver, and audio operations. Our second choice is the Standard Horizon Quest.

 

Also With This Article
"Value Guide: VHF Radios Under $160"
"Digital Selective Calling Update"

Contacts
• Standard Horizon, 714/827-7600, www.standardhorizon.com
• Icom, 425/454-7619, www.icomamerica.com
• Uniden, 800/297-1023, www.uniden.com
• West Marine, 800/262-8464, www.westmarine.com
• Raymarine, 800/539-5539, www.raymarine.com

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