VHF Radios Go Digital

September 21, 2007

Imagine picking up the microphone of your VHF radio from wherever youhappen to be fishing and effortlessly placing a telephone callto any number in the world. Imagine further that this phone callis digital, private, and available 24 hours a day, even far fromsight of land, beyond the reach of other technologies like cellulartelephone service, and all at a surprisingly affordable cost.Sound far-fetched? Not hardly. It’s actually right around thecorner.

Unless you live in somesort of self-imposed media isolation, you’ve no doubt read aboutthe future of information retrieval and dissemination. Those whoenvision such things for us say that soon we will get all of ourcommunications services, including news, internet connection,shopping services, telephone service, banking, etc., from oneprovider, probably through our television sets. We will all beconnected to one another through one giant information web, andour old methods of gathering information will go the way of thedinosaur. It’s the digital revolution.

What’s this got to dowith your VHF? Well, just as technology has transformed televisionand computing from basic tools into essential communications devices,so will it transform your VHF. Yes, the VHF is about to go digitaland become a truly high-tech piece of communications equipment.


The DSC Option

We’ve written a lot aboutDigital Selective Calling (DSC), which is the internationallymandated protocol for transmitting a variety of message formatsbetween SOLAS convention (International Convention for Safetyof Life at Sea) ships and shore stations. For the recreationalfisherman, DSC translates into dedicated channels that are reservedfor emergency purposes. A distress call sent out on the appropriateDSC channel, from a DSC-equipped VHF, will automatically summonhelp.

But on the horizon arenew advantages that DSC will bring. A couple of years ago, wewrote about MariTel, the company that was buying up all of thelocal marine operator systems around the country to form a new,consolidated network. That operation is ongoing, but MariTel hassubsequently jumped into the DSC business with both feet, andplans to offer an incredible range of services to boaters in thenext couple of years.

The MariTel Network

MariTel is building acommunications system that will allow you to make the types ofphone connections described earlier by building a series of talltowers (nominally 330 feet tall) and base stations that will connectfuture-generation VHF radios to America’s phone system _automatically!_Using technology much like that found in cell phones, youwill be able to place digital phone calls, or send emails andfaxes if your boat is equipped to do so, on specific DSC channelsprogrammed into your VHF.


How It Works

Here’s how it will work:MariTel has formed a team to build a system called MariNet. Membersof the team include the American Tower Corporation, which willbuild 286 towers around the coastal United States and the inlandnavigable waters of the U.S. for seamless, contiguous coverage.MariNet also includes the Harris Corporation, which is designingthe base stations, including equipment and software that willprovide overall system integration. Harris will also design, test,and certify procedures for VHF manufacturers.

Williams Communicationsis in charge of designing an Asynchronous Transfer Mode (ATM)backbone that will connect the MariNet coast stations, controlcenters, and other related facilities. This backbone will providecompletely independent and redundant fiber optic pathways, andthe whole thing will be tied into the Public Switched TelephoneNetwork (PSTN) at multiple locations by MCI-Worldcom.

The MariNet system willconsist of intelligent nodes located along the coastline whichwill be able to communicate with properly equipped vessels byvoice or data over VHF at 14.4 kb, and then at network speedsfrom node to node over the ATM. All MariNet base stations willbe digital and capable of simplex or duplex operation. The mainthrust of this system is towards commercial vessels and the transferof data. Fleet operators will be able to send huge amounts ofdata over MariNet efficiently and quickly, and can even establishfleet monitoring and tracking systems.


For those of us who simplywant to stay in touch, phone service will be available at thetouch of a button. Jim Tindall, MariTel’s Vice President of Salesand Marketing, uses a land-based analogy to explain his company’svision. “What we’re doing is essentially the same thing Nexteldid with the land mobile SMR (special mobile radio) system inthe 1980s. Nextel starting buying up all of the small, independentmobile radio systems in the 800 MHz range and consolidated theminto a seamless network that is now the Nextel system we all know.We are trying to accomplish the same thing in the 156 to 162 MHzmarine VHF market. It’s really a reinvention of the marine VHFradio. We’re taking a tired 1970s technology and breathing newlife into it.”

New Radios to Come

The radios that will supportthis new service are decidedly not your father’s VHF. They willobviously have to be equipped with circuitry to handle the newDSC channels, and will no doubt be more expensive than entry-levelradios. And the number of manufacturers willing to invest in thisnew technology may depend upon the amount of demand for thesetypes of services. Some VHF manufacturers are already workingon sophisticated radios which will offer true duplex, digitalDSC service. This will make talking on DSC channels like talkingon an ordinary telephone. And the FCC’s move to allow 12.5 kHzchannel spacing (current radios have 25 kHz spacing) will makeeven more DSC channels available to handle all of the traffic.

Even if you don’t wantto invest in the new-generation VHFs that are coming, it’s importantto note that MariNet’s system emulates today’s analog, half-duplex,and simplex radios. And the company still maintains its staffof marine operators so you can access the system with non-DSCradios, which will be available indefinitely. The operators probablywon’t be there forever, though, as automation makes service fasterand more efficient 50 NM Range.


An obvious question thatarises is why you wouldn’t simply use a cell phone to make thesecalls. After all, most of us own at least one already. The answeris range. MariTel says that its towers will provide seamless,overlapping coverage out to 50 nautical miles from shore, a featthat cellular phones can’t touch. Cellular coverage remains spottyin many coastal areas, and reception is hardly reliable offshore.MariTel says that MariNet’s Public Coast Station towers will eachhave a Radio Direction Finder (RDF) antenna on top that will obtaina line-of-bearing on a one-second voice transmission from a marinechannel 16 transmitter with one-watt effective radiated powerand an antenna height of two meters, at a range of 20 nauticalmiles or more. Translation: they can lock in on a handheld VHFsignal, on low power, six feet above the water’s surface, 20 milesaway. That’s impressive reception.

Like cellular providers,MariTel will offer different airtime plans, but long distanceis included in the pricing, and the rates will be extremely competitive.It all adds up to more communication options for those of us whofish offshore, and the convenience factor alone will be phenomenal.These developments will let us stay in touch as never before.Of course, many of us fish to get away from phones, but that’sthe beauty of a VHF: it’s there when you need it, but you canalways turn the darn thing off!

For moreinformation on the MariTel system, contact: MariTel, 16 East 41stSt., New York, NY 10017; (888) MARITEL.


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