What is a “BDU?”

Steering wheel of an old yacht. White ship and captain's cabin view of the ocean, sea. Stock photo for tourist design

Satellite internet for marine is the latest trend. Satellite TV is great, and it’s been very successful for the last 15 years. But just as traditional television isn’t always enough at home, you probably want to be connected on your boat as well. That’s why thousands of boat owners will add satellite-delivered internet (VSAT) to their boats this year. Will you be one of them?

Attack of the acronyms

As with all technology, satellite internet has its own acronyms, indeed its own language. If you delve deep into it, you’ll be surrounded by terms that you never knew existed. Take for example, “VSAT,” which I casually rolled off in the last paragraph. I go into great detail here, but VSAT stands for “very small aperture terminal” and essentially means satellite-delivered internet.

Another term you’ll hear is “BDU.” It essentially means the modem that connects your marine satellite dish to a router or Wi-Fi system. Think of a BDU as the equivalent of the cable modem in your house. It takes a coaxial cable and translates that into usable Ethernet networking so you can build the network you need in your boat.

The BDU controls the dish — also called an ADU — making sure it’s tracking the right satellite, checking to make sure the signal quality is good enough to use, and applying any configuration changes that need to happen. Unlike the ACU (antenna control unit) used for marine satellite television, BDUs are not generally made by the same company as the satellite dishes themselves. However, they are more flexible and can be configured to work with a variety of different hardware.

BDU? ADU? What?

Here’s the part where you get a little chuckle. BDU stands for “Below Decks Unit.” In other words, the part of the system that’s inside the cabin. That makes it much easier to explain “ADU,” meaning the part of the system that’s out in the elements. By now you’ve guessed it… it stands for “Above Decks Unit.” You have to figure that the engineers who named these things either had no sense of humor, or the best sense of humor ever.

The BDU also acts as a receiver, much like a satellite receiver, controlling access to the internet. If it’s properly activated, you connect to the internet service provider and everything works. The BDU helps you work within your internet plan and makes it possible for you to get internet service from your provider. In this sense it acts like the optical network terminal at home. It communicates with the service provider.  Then it makes sure that you’re authorized to keep surfing the web.

No matter what they call it, you need a device like this. Marine satellite antennas are full of all sorts of logic and can work independently, but they need to know where to point and how to connect.

You don’t have to be an expert at this stuff…

…when you have top-quality customer service. Signal Connect, the marine, commercial, and activation arm of Solid Signal, is full of professionals who can help you get on the internet whether you’re at home, at the office, on the road, or on the water. You’ll get white-glove service when you call the experts at Signal Connect. You’ll get someone on the other end of the phone who understands the special needs that marine users have. We won’t send you to a call queue… once you start a relationship with your representative they’ll always be available to you.

It starts with a call to 888-233-5834. Our staff will help you get on the path to great internet service! If it’s after business hours, fill out the form below and we’ll get right back to you!

About the Author

Stuart Sweet
Stuart Sweet is the editor-in-chief of The Solid Signal Blog and a "master plumber" at Signal Group, LLC. He is the author of over 8,000 articles and longform tutorials including many posted here. Reach him by clicking on "Contact the Editor" at the bottom of this page.