Features March 2007 Issue

Marine VHF Antenna Test

Reach out and touch someone: Testers get the scoop on deck-mounted 6-dB and 9-dB marine VHF antennas. They’re big. They have great range, and they’re great as a backup to your mast-mounted VHF antenna.

For this test of 8-foot and 16-foot fiberglass pole antennas, Practical Sailor contacted the three most popular manufacturers of marine recreational VHF antennas—Comrod, Digital Antenna, and Shakespeare—and requested their participation in our at-sea evaluation. While the distance test produced some interesting numbers (like 23 miles of range for a deck-mounted VHF antenna), a hacksaw revealed some of the most telling details. Digital and Comrod score high for durability, while Shakespeare’s antennas offer good performance at a good price.

 

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As we pointed out in last month’s review of 3-dB VHF antennas ("
VHF Antenna Face-off," February 2007), a mast-mounted 3-dB antenna’s more oval radiation pattern offers sailors the best compromise between range and output when the boat is heeled. However, when the boat is at anchor or under power, you can achieve acceptable performance (though probably not better) with a high-quality,

VHF Antennas
Testers installed the seven 8-foot test antennas on the T-top of our test boat, a 26-foot Scout. The three 16-foot test antennas were mounted to a platform 5 feet above the waterline.
deck-mounted 8-foot or 16-foot fiberglass whip. In fact, many cruising boats carry a standard 8-foot whip to be used in an emergency such as a dismasting.

For this test of 8-foot and 16-foot antennas, Practical Sailor contacted the three most popular manufacturers of marine recreational antennas Comrod, Digital Antenna, and Shakespeare and requested their participation in our "at-sea" evaluation. They responded by sending a total of 10 different antenna models.

Shakespeare sent us five 8-footers, ranging from $36 to $100. We also tested 8-foot models from Digital (529-VW) and Comrod (AV 60 BI8). Each of the 8-footers have a 6-dB output, which theoretically offers greater range than a 3-dB antenna of the same height. However, the narrower radiation pattern means that the 6-dB signal may be directed into the water when the boat is heeled.

The field of 16-footers was much smaller, with one antenna from each of the three manufacturers: the Shakespeare 5018 (171/2 feet), the Comrod AV90312 (16 feet), and the Digital 532-VW (16 feet). The Comrod and Shakespeare are 9-dB antennas, while the Digital model is rated at 10 dB. Although these antennas have a greater potential signal strength than either a 3-dB or 6-dB unit, the relatively narrow radiation pattern is even more prone to being directed downward into the water on a boat that is heeled.

These antennas make, easy-to-service backups that would function well on a multihull or on a monohull that is under power or at anchor. They have the advantage of a shorter coaxial cable, where a surprising amount of signal strength is lost in a mast-mounted antenna. However, their directed radiation pattern makes them unacceptable as a primary antenna on a monohull, and mounting limitations make them generally inferior to a mast-mounted 3-dB antenna.

Comrod

The Comrod company designs and manufactures a complete and very high-end line of yacht and commercial marine antennas at its headquarters in Tau, Norway. Launched as a fishing pole maker in 1948, Comrod began targeting U.S. recreational boaters in 2000 with an entirely new line of pleasure craft antennas.

The Comrod antennas Practical Sailor tested all came without attached coaxial antenna cable, which is optional. When we looked into the situation, we discovered an installation exclusive that Comrod enjoys over its competition: On the bottom of each Comrod antenna, inside the base of the mounting ferrule, is a male BNC antenna fitting where the antenna’s coaxial cable would connect via a female BNC connector. The female connectors swivel 360 degrees, which means one could thread a Comrod antenna down onto a mounting base without the coaxial cable twisting up. Comrod provides a little plastic "cable tool" with each antenna that slips over the antenna coax and helps land the female BNC connector inside the antenna’s ferrule. This "no-twist" cable feature and the ability to thread and un-thread a Comrod antenna off its mount without worrying about the attached antenna coax is especially important on VHF antenna installations where the coaxial cable needs to be longer than the standard 20 feet. Coax runs requiring more than 20 feet on a Shakespeare or Digital antenna would necessitate a cable splice, which causes signal loss.

Comrod does offer RG-58 coaxial cable kits in 5-, 7-, and 12-meter lengths for more standard installations. However, low-loss RG-8X, which is readily available at most marine stores, would be a better choice of antenna cable, in our opinion.

In our performance tests, both the 8- and 16-foot Comrod antennas finished behind the Shakespeare and Digital antennas.

Back at our shop, when we sawed each antenna lengthwise, the Comrods gave us quite a workout they’re filled with a dense polyurethane foam, a Comrod exclusive. Filling the antenna with foam is said to lock out any condensation that would form inside the antenna due to temperature changes, subsequently corroding the antenna’s copper and brass radiating elements. We think that the use of foam is a good idea and will probably keep the conductors inside of these antennas corrosion-free for life. Each Comrod 16-foot antenna also comes with a locking set screw and a tube of Loctite to insure that the antenna’s two sections do not disconnect.

Bottom Line: Although the Comrod antennas came up a little short in the range test and are expensive, their tubes are definitely overbuilt and should last a long time.

Digital Antenna

Digital Antenna Inc., based in Sunrise, Fla., is the only manufacturer in this test that makes its antennas in the U.S.

The fit and finish of both the 8- and 16-foot antennas is impeccable, and Digital uses a custom RG-8X coaxial cable with an added layer of foil shielding beneath the tin shield. Cables provided with the Shakespeare and Comrod sticks do not have this additional shield. With the extra layer of foil, Digital’s coax exhibits the lowest loss of signal per foot, according to the company.

Another nice touch: Digital uses a factory-installed, gold-plated mini-UHF connector on the end of the antenna coax. The connector is roughly the same diameter as the coax cable, which means that you don’t have to cut this connector off or core out any large holes to run the cable through your boat. Connecting the coax to the back of the radio is a snap. Digital provides a slick mini-UHF to UHF male (commonly referred to as a PL-259) adapter, which is also gold-plated and screws onto the mini connector.

In our performance tests, the Digital antennas finished third to a pair of Shakespeare antennas in the 8-foot category and second to a Shakespeare in the 16-foot group.

The 16-foot Digital has one huge brass-and-copper element that fills the entire antenna void. Not only was the Digital full of expensive materials, but its design was impressive.

When we cut open the Digital 8-footer, we observed a very well constructed, custom-looking radiating element that was similar in scale and stature to the 8-foot Comrod and the Shakespeare XT /XP products.

Bottom Line: Even though they are expensive and their range fell short of the Shakespeare test models, the Digital antennas, in our opinion, offer great value because they are built with high-grade materials. If you want an antenna that will last for the long haul, the Digital antennas are excellent choices.

Shakespeare

Founded in 1897, the Shakespeare company is credited with manufacturing the first fiberglass marine antenna (a double-sideband AM antenna) in 1954.

Our test group included three antennas from Shakespeare’s Galaxy lineup, the 8-foot 5225 XT and 5225 XP, and the 16-foot 5018. These antennas are coated with a high-gloss, UV-resistant polyurethane that protects the antenna’s fiberglass strands from yellowing, deteriorating, and becoming fiberglass shards (as was the case with some of Shakespeare’s earlier antenna models).

The Galaxy antennas have a precision-cut radiating element that is said to have an ultra-low angle of signal radiation, yielding maximum range and minimum fading when compared to most other antenna designs. Last year, Shakespeare engineers added silver-plating to the radiating element of its flagship 8-foot, 6-dB XT Galaxy antenna, creating the new "XP" model.

During the installation and dockside check of the 8-foot Shakespeare Galaxy antennas, we noticed that the more expensive XP rattled excessively when screwed onto its four-way mounts. The backup XP antenna also rattled when we gave it a shake. Shakespeare’s Don Henry said the rattling occurs when the cable inside the element slaps against the side of the brass elements, but that this in no way impacts performance or durability of the antenna.

Shakespeare provides 20 feet of low-loss RG-8X with its Galaxy antennas. This is quality coax, but not as high-quality as Digital’s double-shielded coax with the factory-installed mini connectors.

Other than being silver-plated, the radiating element inside the XP antenna was far less substantial than that of the Digital 529-VW. And the elements inside the big Galaxy were anorexic, in our opinion, joined together by RG59/75 Ohm cable and supported at the antenna tip via a small shock cord and a brass barrel swivel. "Looks can be deceiving," said Henry. "While the materials may not look that impressive, they are very well designed."

On the water, the 8-foot Shakespeare 5225XP Galaxy and the 17-foot, 6-inch Galaxy 5018 decisively outdistanced the others.

We also tested Shakespeare’s 8-foot 5202 Pro, the Centennial 5102, and the Economy 5206-C. Shakespeare’s 5202 is a well-respected antenna that has a proven track record, but lacks the high-gloss finish of the Galaxy product. The Centennial is good for near-shore boating where maximum range is not a priority. The Economy 5206-C ranked dead last in our range test, with 50 percent less range than the Galaxy XT. All that is inside of the 5206-C antenna is a stripped back piece of inexpensive coax cable.

Bottom Line: Shakespeare’s Galaxy antennas performed the best in our test. They are priced right, and readily available at most retailers. For someone closely watching their expenses, the 5335 XT or 5335 XP are good choices. The 5018 is our Budget Buy for the tall sticks.

Conclusion

In the 8-foot, 6-dB category, Shakespeare’s 5225 XT and XP held a slight range advantage over the Digital 529-VW. These two Shakespeare antennas are not as rugged as the Digital, but they cost significantly less. At $82, the 5225 XT earns Budget Buy honors. We were impressed with the price and performance of the 5225 XP, too, but we think Shakespeare’s top-of-the-line antenna should not rattle at all.

With its exceptional range and top-quality construction, the Digital 529-VW is a good choice. The Comrod is built to last, and we recommend it.

Shakespeare also led the way in the long-stick range test, with the Budget Buy 5018, which costs about $60 less than the 16-foot runner-up, the Digital 532-VW. Shakespeare 5018’s had the longest range, but it wasn’t as rugged. The Digital and Comrod, based on our examinations of their innards, should withstand years of rough use. The Digital is $100 less than the Comrod, so it would be our top choice.

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