Marine Electronics

Special Report: How to Prevent AIS and VHF Antenna Malfunction

Safety of Life at Sea (SOLAS) ships-including tankers, passenger vessels and cargo ships over 300 gross tonnage-must be equipped with Automatic Identification Systems (AIS). In the U.S., carriage requirements also includes vessels over 65-feet. AIS can allow you to see a distant ship, but is not a substitute for radar.

Register Your VHF Radio

The U.S. Coast Guard continues be concerned about the misuse (or lack of use) of VHF radios for distress calling. Many boaters, it seems, don't understand the importance of registering their radio equipment, and how to properly use Digital Selective Calling (DSC) feature. Here we offer a brief overview of the most frequently asked questions regarding DSC. More information can be found at the Coast Guards Navigation Center website, www.navcen.uscg.gov.

Testing VHF Coaxial

The loss in RF coaxial cable increases substantially and quickly, when there is water intrusion. Coax that uses foam dielectric, like RG8X and LMR type coax, is particularly prone to this problem because the water can quickly propagate along the foam dielectric used in these type coaxes.

Antenna Gain and VHF Transmission Range

Recreational marine VHF antennas are usually broken down into three categories: 3- and 4-foot sailboat antennas (3dB gain), 8-foot powerboat antennas (6 dB gain) and 16-plus-foot, long-stick antennas (9+ dB gain) that are popular on larger, long-range craft. Antenna gain is a ratio related to an antennas effective radiated power (ERP) instead of a fixed quantitative value.

Heat-Seal Connectors

A typical cruising boat has thousands of electrical connections. The consequence of failure range from a light that doesn't work to a fire that can cost lives.

Mailport: Low Budget Navigation

Regarding the article on recycling gear for cruising in the September 2018 issue, I found that an old Windows laptop, with an external GPS puck and running OziExplorer, makes a fabulous chartplotter. The software is just a hair over $100 and is capable of using NOAA charts, USGS topo maps, aerial photographs, and any other map that can be put in registration, using only latitude and longitude of a couple of points on the map.

Internet of Things Goes to Sea

Version 1.0.0 of Signal K, the Open Marine Data Standard has now been released, giving developers a stable platform to test and develop new open-source hardware and software for sailors.

Testing the B&G Zeus3 Nav System

Multifunction display manufacturers have pushed their products through a dramatic evolution in the last five years as they try to keep pace with technology that we take for granted in our other electronics. Better interfaces, screen resolution, and the ability to download useful software apps (beyond navigation) are just some of the improvements. Most of the major vendors are on their third generation of touchscreen interfaces, higher resolution displays, downloadable software, remote music control, and other functions far afield of what MFDs performed five years ago.

Mailport: EPIRB Battery Shocker

We have an ACR Global Fix EPIRB and an ACR Aqualink PLB. We had the EPIRB battery replaced 5 years ago in the USA, and it is time again to do so. We are currently in New Zealand and have been given a quote of close to $350 to replace the EPIRB battery and $120 for the PLB.

Blue Seas New Smart Charger

Keeping batteries fully charged is a science that cruisers have to master sooner or later. If todays high-capacity AGM batteries arent managed properly, valuable amp hours in can permanently trickle away through sulfation, as we saw in our test of AGM batteries (See Fighting Sulfation in AGMs, PS May 2015). Good battery management means complete re-charging that matches the charging profile of your battery, and this means an accurate sensing of battery voltage. As we saw in our recent report on battery monitors (see Best Battery Monitor Test Update, PS October 2017) a good monitor will also keep track of temperature, as this can be a limiting factor in charge acceptance rate.