As John said, this is a little like religion. I’ve owned a few dozen HF radios over the years. One of my hobbies is restoring them. Each have advantages, receiver performance, ease of use, filters, band coverage, operator interface, frequency stability, and optional features. None of the marine radios that I’ve owned or seen can compete with a good HAM radio, but HAM radios are not type-approved for use on the marine bands. There are some marine radios that are type-approved for amateur use, but this is not the same thing. I keep two HF rigs on the boat, and ICOM-706 and an SGC-2000. The 706 is a decent radio, but is not outstanding. You can buy a good used one for about $400. The SGC works OK on the marine bands, but is really not a very good radio. The matching tuner is nice however. Some folks use their amateur radio on the marine bands. This is technically illegal, though some amateur radios have stability specs that are as good as the marine radios.
So what’s the best radio? It all depends on what you want to do with your HF radio and how much you are willing to spend. If you just want to get on the marine bands when offshore, a contemporary marine SSB would work fine. If you want to keep in touch with your cruising buddies over long distances, you would probably find a HAM radio to be of more value (along with the license to go with it).
So what’s a band? Frequency allocation is done by the FCC in what are called bands. The FCC will grant use of a contiguous set of frequencies to a radio service. This is called a band. In the case of both the marine and amateur services, there are band allocations scattered in the HF spectrum. Because of the odd behavior of radio waves over long distances and the influence of sun light and sunspot activity, different bands can be used for communication over different distances at different times of the day.
So what’s the difference between marine bands and amateur bands? Marine bands are channelized much like a marine VHF radio. You dial in a channel number. While you are probably aware of the band you are working on, the actual frequency is of little consequence. Marine radios are designed for appliance operators. These are folks who just want to make a contact with another station and don’t want to be bothered with making adjustments to the radio to make the received signal sound better.
Traffic on the marine bands is usually specific to marine operations, though you may hear private conversations at times. Amateur band traffic is usually of three types, contest operations, net traffic, and private conversations (aka rag-chewing). Transmissions are done on random frequencies within assigned bands. Contests are what they sound like. You enter a contest and get points for making contacts with other stations. Points are awarded based on rules like where the other station is. Net operations are done at pre-arranged frequencies and times for a specific purpose. The marine mobile net is a good example. Here cruising folks can check in to see if anyone has left a message for them.
So what makes one radio better than another? Receiver sensitivity, selectivity, and noise suppression (filtering) are probably most important. The difference between two radios connected to the same antenna can be quite dramatic. My SGC is deaf in comparison with the ICOM-706 next to it. I can receive and copy stations on the 706 that I can’t even hear on the SGC. The 706 is deaf when compared with an Elecraft K2 I have at home.
Wefax is usually transmitted on a band that is neither in the marine bands nor the amateur bands. The transmission is in a government allocated band. The US has discontinued wefax transmissions because it cost a few hundred grand each year to keep the stations on the air. You can still receive wefax broadcasts from Canada and overseas under the right conditions. You can also receive precise time of day. Most but not all marine and amateur radios can be tuned outside their approved bands to receive wefax and time. You can copy wefax, navtex, and other digital mode broadcasts using either free software or purchased software. Although you can probably connect your laptop microphone jack directly to your radio speaker output, I would recommend buying an interface box to isolate the two pieces (approx $150).
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Rich Carter – BlackSheep #47
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