Can You Hear Me Now?
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 www.antennaguy.com.)
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.
This article originally appeared in the May 2004 issue of Power & Motoryacht magazine.