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.
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.
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.
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.
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.