|
|
:: customer & installer login
|
|
|
|
|
Find the answerers you need
Managing your computer's serial ports
Many people run out of available serial ports when they try to connect a GPS, autopilot, radar, and such to their computers. Many of these devices speak a common language, known by its standard designator NMEA-0183. This language was created by the National Marine Electronics Association in order to allow different types of on-board electronic devices to be able to communicate with each other. A NMEA multiplexor combines the signals from many different devices onto one cable which can then be connected to your computer. In this way, you can typically connect up to 4 different NMEA-compatible devices using only one serial port on your computer.
Contact us for more information on managing your computer's serial ports.
Connecting your GPS to your computer
Most models of GPS receivers have an optional "data" or "PC" cable that you can buy (or make) to connect your receiver to your computer. This will allow your navigation software to plot your position on a display chart, and your weather software to accurately capture and map satellite data. One end of the cable will fit into the back/bottom of your GPS receiver and the other end will probably have a connector with room for 9 pins (5 in the top row and 4 in the bottom row). This end should have a matching connector on the back of your computer. This will sometimes be labeled "serial", "COM", or "10101". Once you've made the connection, you're halfway there.
Now you've got to tell your GPS to start sending information out over this cable. The method for this will depend on the make and model of receiver you have. Most GPS receivers come from the factory with this option disabled. To enable it you can usually select "NMEA output" or something similar from a menu on the receiver -- check your manual for details. You'll have to tell your computer (actually the software on your computer) where to start looking for the incoming data. There should be a choice of COM1, COM2, COM3 or COM4. Try COM1 or COM2 first - one of these will usually work. If not, then try COM3 or COM4. You can't do any harm by picking the wrong one. Check your software's instructions for details.
To be safe, you should install an opto-isolator between your GPS (and any other NMEA device) and your computer. This opto-isolator allows normal signals to go through, but blocks any high voltage signals due to lightning, short circuits, and ground faults. These signals can cause massive damage to parts of your computer, usually requiring replacement of components which would be at the least inconvenient and possibly impossible at sea. Opto-isolators are a relatively inexpensive way to protect your relatively expensive investment in a computer.
Contact us for more information on connecting your GPS to your computer.
Powering your on-board computer
The best way to supply power to an on-board computer is a topic of frequent debate with no "correct" answer. For most people, the simplest way to provide a clean source of power is through an inverter that runs off of the ship's battery bank. This allows you to plug your computer directly into a normal outlet and run with the power supply that was originally provided with the computer. The disadvantage of this setup is that you are converting the battery's DC power supply into an AC source, and then back to DC to power the computer. This is a certain lack of efficiency in this method, though it's typically small (e.g., <0.2 amps). The advantages are that the inverter and power supply clean the power that's supplied. That is, they smooth out any peaks and sags in voltage as well as remove a considerable amount of electrical noise that's typically found on the battery's direct supply. If you choose to connect your computer directly to your vessel's battery bank (bypassing the computer's 110 volt power supply), be sure to include spike protection and noise suppression to the circuit.
Of course maintaining appropriate battery charge is of utmost importance. As your battery discharges, it's voltage will drop slowly. Most electronic devices have a threshold voltage, below which they won't work. This is true both for your computer as well as your inverter. If you reach this threshold voltage while you're operating your computer, you may cause some damage. Keep in mind, that other large drains on the battery (e.g., a starter motor) will cause the battery voltage to drop below the normal level. If you intend to run your computer while starting the engine, make sure the computer is connected to a separate (e.g., house bank) battery then your engine's battery.
Contact us for more information on powering your on-board computer.
Which inverter is right for me?
There are several different flavors of inverters available. Two key technologies that you'll see mentioned often are "true sine wave" inverters and "modified sine wave" inverters. The modified sine wave inverters are generally less expensive than the true sine wave inverters and produce an alternating current that's not quite as clean as what you'd get from the power company, while the true sine wave inverters sometimes give out a signal that's cleaner than shore power! In addition to the added cost of a true sine wave inverter, you'll find them to be less efficient at converting DC power into AC. They also tend to have a higher standby power drain. That is, if you don't have anything plugged into the inverter, but merely have it turned on and connected to your boat's batteries, the power drain will be more significant on a true sine wave inverter than on a modified sine wave inverter.
For most resistive loads (heat generating appliances - coffee makers, hair dryers, light bulbs), the type of sine wave really doesn't matter. However, some electronic devices prefer the true sine wave. In the end there's no clear and easy choice.
Contact us for more information on choosing an inverter.
Browsing the web without wires
The most frequently encountered way of connecting to a network while underway is to use a cellular phone with a special cable to hook it up to your modem. An alternative is to use a cellular modem card. This is essentially a cellular phone on a PCMCIA card. This means you don't need to bring your mobile phone along -- you just attach a small antenna to your computer and log on.
In either case, if you connect to the Internet and browse the World-Wide Web, you'll find yourself quickly dissatisfied with the amount of time it takes to display a web page. A simple solution is to show only the text on the page, and ignore the pictures. Pictures are notoriously large files - leading to long download times. Even a very, very small picture often takes as long to download as two thousand characters of text! Most browsers have a setting that will disable the display of pictures. Even when disabled, you can usually display individual images here and there when the need arises.
Contact us for more information on wireless connectivity.
Email and safety from the high seas
One of our most frequently answered questions is, "How can I send and receive email from the high seas?" There is a small, no-nonsense, reliable system that not only allows you to send and receive email, but also gives you free offshore weather and safety information, and comes with a built-in GPS-enabled distress beacon.
The system is based on Inmarsat-C technology and even though it's in use aboard many large commercial ships, the components are affordable and small enough for the average yacht. The omni-directional antenna is slightly larger than a grapefruit and can be mounted almost anywhere. The transceiver is about the size of a large book and can be tucked safely below decks with minimal power draw for receiving transmissions. The Inmarsat-C satellites are always in sight - no waiting for one to pass overhead!
Contact us for more information on wireless communications.