WiFi Boosting with the Bowltenna

If you've tried to use WiFi from your boat, you've probably found that from down below decks you have spotty coverage at best. You may have invested in a USB WiFi “thumb” device with an extension cord ($20 and $10, respectively), and still found that you can't pull in the signal that you need all the time. Before you think about investing in some permanently mounted, probably illegal and certainly costly ($400 to $1000) antenna rig, let me tell you how to even more dramatically increase both the quality and strength of your signal with stuff you already have aboard (and at home, and can get from room service).

First let me elaborate on the legal aspect I mentioned above. In the US, it is illegal to modify a WiFi radio, and it is illegal to use a home-made antenna, and it is illegal to amplify your signal. In fact, it is a (dark) gray area whether you can use any aftermarket antenna at all. We've contacted the FCC for clarification on this and on our design, and they have thus far declined to comment, but it is clear that the “cantenna” and other devices are specifically illegal, and many mast-top units may be just as likely to earn a hefty fine. Whereas our design will very likely not.

The reason why the bowltenna doesn't fall into this gray area is that it's not an antenna, it's simply a reflector. As a reflector, it shields others from the transmission of your radio, and is thus something the FCC actively encourages. Whether we'll see official FCC approval is doubtful, but I'm trying.

Now, what you will need is a radio. The perfect solution is a cheap USB thumb wifi unit like I mentioned. $20 online, with a $10 extension cord, and you will have made your entire investment. You may find that by just repositioning the radio inside the boat, you'll have the reception you need. This is because inside the boat, the radio waves bounce all over the place, and sometimes there will be spots where they focus. This means you have a boat-tenna - your boat is acting as a reflector.

Even if this boat-tenna works fine, there will be times or places where you may want a bit more oomph. Now, you can certainly make this difficult if you like that sort of thing. There are all kinds of gadgets out there, and you can get out the blowtorch if you'd like, but what I use is just about as easy to make as mud. So, your choice.

Now, considering that you have a radio or antenna that you can move around, you're going to need to direct, or focus, the signal. The degree to which you can focus the signal is called gain, and measured in decibels (dB). You can build a bowltenna that can get up to 15dB gain, but you're likely to max out at around 6-9dB gain with the size and shape of most bowls. Since strength doubles with each 3dB, we're talking a 400-800% improvement, with a potential of 3200%, and we're going to use legal and unadulterated equipment to do achieve this.

Oh, and some cookware.

Ideally, we want our cookware to be a perfect parabola - the cross section a sine wave - like a microwave dish antenna. These exact shapes don't generally exist on board (unless you have DirectTV), so the closest thing is usually a wok - grab one if you've got it. No wok? A stainless mixing bowl may do the trick, the bigger the better. How about a metal colander, or a plastic bowl lined with foil? Ingenuity is the mother of invention, so get creative.

What happens is the signal will be reflected by the bowl, onto the antenna. For the first step, point the bowl at the source of the signal (marina, yacht club, cafe, neighbor) as if you were trying to catch the signal in the bowl, which you are. A clear line of site you can comfortably reach with your cord is usually best, but we have no trouble going right through our hull with a 12” bowltenna, so you don't have to do a lot of acrobatics. Use whatever you need to prop the bowl in the right direction, and now you're simply going to put your antenna in front of (not touching) the center of the bowl - set it on something plastic, wood or cardboard if you need to raise it up. See, told you it was easy as mud!

You'll need to move the antenna around a bit to find the best focal point, and it really pays to experiment with both placement and what you use for a reflector. Since you're basically only pointing at one radio, your bowltenna will have much less interference than with even hi-gain omnidirectional (stick) antennas. So, we almost always get far better signals than any of our mast-top-equipped neighbors, and man does that make them mad!

The simple and cheap solution almost always works best for us. Let us know how this one works for you, and any simple solutions to common problems you yourself have come up with while on board. Maybe next time we'll cover how to make a backup depth sounder with a rock and some string!