Here is some advise I hope some of you guys will find useful. I have a lot of experience with HF and very low power
levels, down to 100mW (yes, milliwats!). Not marine
, but Ham Radio, but HF is HF, no matter what radio you use.
Some knowledge of propagation is required to use HF efficiently. There is no better way than getting into Ham radio for that. Basically, lower frequencies work better at night, and higher ones during the day. It's more complicated than that, but that is the jest of it. The problem with lower frequencies is that antenna length requirements become a real problem. To find the ideal antenna length (half wave), divide 468 by the frequency. Ex: 4mHz, 468/4=117ft. I don't think I've ever seen a mast
that long! Ideally you would have one antenna per band. Of course people don't do that so they use a compromise antenna with a tuner. The problem with tuners is that in order to match the impedance of the antenna at the given frequency, a lot of the power you put out is just lost
in producing heat. Often, people think they put out 100W when only 10W gets radiated, sometimes even 1W! Not to mention stray RF in the electrical system
if the installation isn't perfect. Antennas are ideal for only one frequency and can work for a few more. For example, an antenna for 7mHz might work for 21mHz (3x7), but the radiation pattern might not be ideal. Bottom line is, you should choose an antenna depending on the bands you are going to use the most, and that can be tricky.
Then you need to consider the modes of communication, data, SSB, CW... Yes, CW, good old Morse code. I'll come back to that later.
You can either spend thousands on a Marine email
system or use a much cheaper Ham radio and the Winlink system. Shopping
wisely, you could probably get a whole system, including the computer for $700.
(General) is very easy to get, usually sets you back $15 and is valid for ten years. You will have to plan any use in foreign waters carefully though. Reciprocal licenses are obtainable, sometimes not necessary.
Marine systems are probably more "turn-key," but they will cost you.
Another consideration is current
draw. My SSB Ham radio draws 150mA on receive, not the 3A of an Icom
802. If you lose your ability to recharge batteries, you won't be receiving for very long, not to mention transmitting!
The truth is that little power is necessary for global range, assuming you radiate most of the power your radio produces. For SSB, 20W will get you anywhere. Maybe not where you want, but somewhere, most of the time. When the propagation isn't there, it doesn't matter if you have 20 or 1000W, it won't work. Hence the need to know which frequency to use at what time of the day, season, and depending on solar
Data on HF is slow, very slow. It requires the radio to operate at 100% duty cycle and uses much current
. You also need a computer of course, and some kind of interface or modem
. It won't work all the time. Not that satellite
will work all the time either... Actually, it might not work when you need it the most, in bad weather. Ever tried to watch satellite
TV in a heavy storm? At least with HF, Marine or Ham, you most likely will be heard somewhere. I would never be at sea without an HF radio
So, about emergencies... After all, the radio is foremost a safety
device, not one to check your email
or sign into Facebook! Personally, I would use Morse code to call for help, even if I had an EPIRB
. I know, it's not for everyone, and certainly not easy to learn. At least it wasn't easy for me. The reason is that Morse code (CW) is like using a laser instead of a flashlight. A 5W Morse code radio is like a 100W SSB radio. Even better I suspect because it is a tone, much easier to hear than voice. I routinely have conversations in Morse code at power levels that would be impossible using voice and most data modes. My favorite radio uses 35mA on receive and 700mA on transmit. It is the size of a pack of cigarettes! Yet I've had great results up to 6000 miles. With a set of eight AA cells, which I can recharge with a small 7W foldable solar
panel, I could be transmitting for months! You also practically always find someone on the air. I used a phone
app called "Ham Morse" to learn the code, along with the lcwo.net web site. It took me more than a year to become proficient. Best avise: Don't learn it below 17wpm (words-per-minute). Try to copy in your head
and not visualize dits and dahs...
A radio is not something you can just pick up and use. You might get away with ignorance on VHF
a bit, but not on HF. Sure, use a lot of power and a tuner, you might get through more often than not, but there is a cost associated with that. Learning
about radios, antennas and propagation will make you much safer at sea.
Becoming a Ham radio operator is a great way to learn how to use any radio more efficiently. Kids
nine years old have passed their General license
... Having fun with Ham radio will teach you a lot...
The guys on 14300kHz are a great bunch, and that alone is a reason to get a ham radio.
I'd be glad to give advise to anyone who is interested...