Sailboat Electronics

A Moveable Feast

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Say “link” to a cruising sailor today and anchor chain is probably not what comes to mind. Reliable Internet access has become a Holy Grail for most cruisers. We are so anxious to be connected that Wi-Fi hotspots now trump most other harbor attractions.

Virtually all new laptop computers have wireless capability, but their range is limited by their antennas and the power of the internal transmitter. You can carry your computer to an Internet caf ashore, but to connect to a distant access point from the boat, you nearly always need a more powerful transmitter and a better antenna. That means a wireless adapter of some kind, connected to a Wi-Fi antenna and to your computer.

There are plenty of pre-packaged Wi-Fi antenna systems on the market, and if you are uncomfortable muddling through computer installations that are not fairly simple, then a turn-key system with customer support and a solid warranty is probably your best choice. However, if cost is also an issue, read on.

The first question concerns how your antenna system connects to your computer. A USB (Universal Serial Bus) connection is the most familiar and perhaps the easiest, because it is essentially plug-and-play—the USB connection provides both connectivity and the power needed to run a remote Wi-Fi adapter. There is software to load and configure, but the biggest drawback is that the maximum cable length is only 5 meters. This works fine for a rail-mounted antenna or a portable one that you plop on the cabintop as needed. You can lengthen the connection for a more remote fixed-mount adapter with an active USB extension, but this typically results in a vulnerable, exposed USB connection. Active extensions can also introduce transmission gremlins.

On A High

I wanted a permanent Wi-Fi antenna at the top of my mizzen mast. I figured the higher position would avert the problem of being blocked by the bulk of other boats in an anchorage; I also believe the radio is better off positioned well above the reach of salt spray. Such a location essentially dictates a PoE (Power over Ethernet) connection, which is made via the socket on a laptop that looks like an oversize telephone jack (which is exactly what it is). With Cat5e cable, the wireless adapter can then be positioned as far as 300ft from the computer. This is the only sensible solution for a masthead installation or even a pole or arch-mounted adapter.

On reviewing the various PoE antenna options currently available, I concluded that many use the same central component, a Ubiquity Bullet2HP outdoor radio device. This powerful unit screws directly to any Wi-Fi antenna with an N-female connector. Add the right length of cable and a little gizmo known as an “injector” that supplies 12-volt power, and you have a complete system.

The choice of antenna raised some issues that will be familiar to anyone who has installed a VHF radio. Essentially, the higher the gain of the antenna, the longer the theoretical transmission distance, but increasing the gain also focuses the transmission in the vertical plane. With a 6dB antenna, you can heel or roll through maybe 20 degrees either side of vertical and probably maintain a connection. A 9dB antenna is essentially twice as powerful, but has half the transmission width, so heeling or rolling through 10 degrees will likely interrupt a connection. Anything beyond 9dB is practical only in a perfectly flat anchorage.

Putting it together

The injector feeds power to two pairs of wires in the Ethernet cable. If supplying 12 volts from a 12-volt source, it is possible to simply tie into the appropriate wires in the Ethernet cable or connector, but this is a delicate operation and is probably not the best way to save the $5 cost of a DC-to-DC injector.

To put everything together, you need the radio, the antenna, the injector and two Cat5e cables, one to run from the radio to the injector, and another to go from the injector to the computer or to a router if you want to connect multiple computers at the same time. A router can also accommodate a Wi-Fi-enabled smartphone. You also need the mount for the antenna, a length of two-conductor wire to supply the injector, and an SPST switch if you want to be able to turn off the power to the radio.

Here is exactly what I settled on: I bought a Bullet2HP radio device for $68.95, after vacillating between the 6dB HGV-2406U antenna ($42.99) and the 8dB HGV-2409U antenna ($49.99), both from L-com. My reasoning was that we avoid rolly anchorages like the plague, and when the boat is rolling, we’re not likely to be staring at a computer screen. For an injector I bought the Air802 Direct Insertion PoE Adapter (Model # PDCPOEVAVADR) for $19.95. I chose this over cheaper models because it has wire terminals rather than a jack for a small coax plug, and I assumed a solid connection would be more trouble-free. I bought a 50ft and a 5ft Cat5e cable through Amazon.com for $5.49 and $2.99 respectively. I opted not to buy the considerably more expensive outdoor cable, because my entire cable run, but for short lengths at the top and bottom of my deck-stepped mast, was either inside the mast or belowdecks. The short exposed sections I simply wrapped with electrical tape for protection. I found the hook-up wire and a suitable toggle switch in my onboard electrical supplies. My entire investment was $147.37, plus a few dollars in shipping charges and the cost of a Cable Clam through-deck fitting to get the wire below.

With all these parts in hand, the installation was dead simple. L-com thoughtfully provided a sturdy U-bolt bracket for pole mounting an antenna. I bolted this bracket to my mizzen mast by drilling and tapping four fastener holes. I also needed to cut a bit out of the bracket to provide clearance around an existing bracket at the top of my mast. Once the new bracket was in place, I bolted the antenna to it with the provided washer and nut. The Bullet2HP radio simply hangs below the antenna, secured with the N-type connector. The cable that leads down to the deck is plugged into a socket in the bottom of the radio and is protected by a screw-on cover.

Because the cables had molded plugs, the two holes in the mast had to be large enough to accommodate them. They turned out to be a “generous” 1/2in each—i.e., a 1/2in hole hogged out slightly with the drill bit. I dropped a weighted messenger line through the hole near the top of the mast and fished it out the hole near the bottom, then used that to run the Cat5e cable. To keep the cable from clanging inside the mast, I added three-legged cable-tie “spiders” at 8ft intervals to hold it away from the mast wall. I also protected the wire at the holes by working split rubber grommets into place. At the top, I wrapped all of the exposed cable with electrical tape, then fixed the cable in place with a drip loop by capturing it with a single nylon cable clamp. I also wrapped the exposed portion at the bottom of the mast, then fed it belowdeck through a Cable Clam deck gland.

In the saloon, I mounted the injector on a bookshelf bulkhead with some webbing and a plastic buckle that I had at hand. A nearby terminal block provided a connection point for the two power wires to the injector, with the positive one routed through a toggle switch. Snaking the cable from the mast through the boat to the PoE socket on the injector completed the installation, but for connecting my computer to the other socket with the short Cat5e cable.

Now what? Fortunately, I had previously downloaded and studied the “Beginner’s Setup Guide” posted at www.ubnt.com/downloads/Nano_Quick_Set-up.pdf. There is no software that comes with the Bullet radio, just the embedded operating system, which you access through your computer’s browser once you have made the necessary local area connection. Everything needed to do that and to get online is included in the 6-page setup guide. My setup took less than five minutes, and when I was done, my computer immediately identified 20 Wi-Fi access points, eight of them unsecured. By comparison, my old antenna only listed six access points, just one of which was unsecured.

I have now had several weeks of use and can report that this setup has been nothing short of terrific. Of course, your mileage may vary, but at anchor with my preferred hotspot about half a mile away, I have had a 100 percent reliable connection fast enough for streaming video. Even more to the point, when a medical emergency required hours on Skype, the connection did not fail or falter.

There are other adapters and other options on the market. This is just the one I settled on. Significantly, it cost me less than the price of a waterproof case for my computer, and it is infinitely more convenient. If you want to follow my example, I doubt you’ll be disappointed.

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