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Can You Hear Me Now?

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Lying handsets, wireless wireless, and other marine cellular shenanigans.

Most of us enjoy the benefits of boating with a cellphone. We can stay in touch with home and work, if desired, or dial ahead for a slip or a restaurant table. That is, until that annoying moment when we cruise beyond the range of the cell towers or our service fails for more mysterious reasons. My challenge this month is to explain how the mess of gadgets and wires pictured above is actually one sensible system for getting the most out of marine cellular.


For more than a year now, I’ve been testing the Digital Antenna PowerMax cellular amplifier and four-foot, 9-dB boat antenna shown in the left portion of the photo above. One of the first things I learned was just how badly cellphones lie! I hunted down the code that unlocks the “field test” menu on my Nokia 5165, a hidden feature on most cells. After doing this I was able to see the same detailed signal-strength readings that technicians use to diagnose problems, as opposed to the “optimistic” graphic meter shown to us civilians. In the photo at right, the -75 figure is true signal strength measured in dBm (milliwatt decibels). The dBm readings work similarly to school grading in reverse; -55 calls are about as good as cell gets, while -100 calls flat out flunk. Though I found that -75 conversations were in the choppy, “Can you hear me now?” style, you can see that my phone awards itself a four-bar “A” for such signal strength.

My Nokia’s regular signal meter doesn’t just exaggerate; it’s also slow to respond to rapid fluctuations in signal quality, a condition I see frequently on the field-test screen and hear as noise and busted words. Are you reminded of your own cell’s temperamental nature? Joanne Johnson, head of marketing at Digital Antenna, says that my phone’s deceptiveness is typical and a source of much frustration. Cell users have a hard time knowing what their phone is really up to, let alone how much an added amp or antenna is actually helping. (By the way, if you want to get geeky, the codes to unlock field testing are available from some cell dealers and on Web sites like

I can tell you that Digital’s gear really works. I often saw 5- to 10-dBm improvements just by attaching my phone to the antenna, another 10 to 15 by adding the amplifier, which also seemed to flatten signal fluctuations. I was the strange guy repeatedly calling my own office answering machine from the boat (and pickup truck, as I also had a 3-dB car antenna) last season. I’d find a marginal reception area and then place separate calls with the cell alone and with the bidirectional booster attached. I could hear the difference both ways, first in my machine’s outgoing message and then when I got home on the messages I left.

Cell signal boosting helps mostly with range. I can’t report solid numbers because of Maine’s irregular coastline and islands, but I’ve read reports of better than 50-mile cell calls off Florida’s well-defined network using Digital equipment, and I believe them. Mind you that cell-saturated South Florida is subject to the phenomenon of decreasing range as it’s populated with more, but smaller-area, cell antennas (see “Saltwater Cellular,” September 2001). My equipment also helped when the signal was partially blocked by a high island or hill. While I still found some dead spots produced by such obstacles, a couple of times I saw my phone go from “no service” (worse than -100) to a reasonable signal, a pleasure that Digital Antenna doesn’t even advertise as possible.

Digital’s gear is also quite flexible. I use the older version of AT&T cellular—which includes 800/1900 MHz TDMA and analog—but the $416 DA4000 amplifier is FCC-approved for all wireless services except Nextel, for which there’s an alternate model. The 561 antenna costs $205 and works with everything, and there are other models in different lengths and/or combined with VHF or AM/FM. Shakespeare Marine has been talking for some time about offering an amplifier similar to Digital’s and recently distributed specs for the $459 CA-819. Reportedly, it will, like the DA4000, wring the maximum allowed power out of any cellphone (again, except Nextel’s) when paired with the right antenna—3 watts in the low band, 2 in the high. In fact, I’ve been testing the Digital gear this long because I was hoping to compare it to Shakespeare’s; a shipping delay due to needed modifications led me to put that project off for now.

While you really can improve cell performance on your boat, one unfortunate side effect is that your wireless phone gets wired.

Shakespeare’s difficulties highlight the fact that cell amplifiers are tricky because, done right, they must modulate their power so as not to overwhelm a nearby tower. There’s actually a lot of controversy about cell amplification. In my research I came across an internal memo from one service provider banning the sale of certain car amps by its own dealers and installers because “testing has shown that the use of these boosters has caused dropped calls and overall poor performance to other customers on our network.” I also found users complaining that towers cut off their calls when they took their amplified phone too close. None of these problems involved Digital Antenna’s highly engineered equipment, but—beware—the offending models are FCC-approved. Digital is trying to further confirm its technology by securing individual endorsements from each cell service and has succeeded with Verizon so far. Shakespeare has the same plan.

While you really can improve cell performance on your boat, one unfortunate side effect is that your wireless phone gets wired. In fact, to minimize line loss, the typical patch cable from amp to phone is only three feet, less than the curly wire on most fixed phones. If you’ve come to enjoy the wireless freedom to pace around while you chat, you’re going to feel tied down. That’s how my experiment led to more gizmos.

One is CellSocket, now being distributed to the marine world by Charles Industries. My Nokia snaps into this secure cradle, which I can leave wired to the amp; it also keeps the phone charged and provides it with a dial tone interface to any conventional phone system. When the cell rings, any connected handset rings, and I can dial out in the reverse direction. The $130 CellSocket will reportedly work with a large yacht’s PBX, such as Charles’s own C-Phone system, or even Raymarine’s 230 black box VHF system, though it’s only available for certain Nokia and Motorola models so far.

I used the CellSocket with Uniden’s nifty new WXI377 submersible cordless phone. It costs just $50, it floats, and I still get to wander around my boat, the handset wirelessly connected to the wired but amped up longer-range wireless. Get it? I call the whole system wireless wireless, and it works quite well (and can be installed in a much more tidy fashion than shown in my lab).

I’ll close with the good news that Digital Antenna has just introduced a simpler, more elegant, form of wireless wireless. The PowerMax DA4000SBR repeater/amplifier promises the same power as the company’s wired amp, only rebroadcast into your boat—no wires. The $559 kit comes complete with a marine antenna (which must be mounted at least 15 feet above the internal antenna) and will boost the phone of anyone onboard, even several simultaneously. A boater thus equipped might find a lot of new friends hanging around in a remote anchorage!

Digital Antenna Phone: (954) 747-7022.

Shakespeare Marine Phone: (800) 845-7750.

Charles Industries Phone: (847) 806-6300.

Uniden Phone: (800) 297-1023.

This article originally appeared in the May 2004 issue of Power & Motoryacht magazine.