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  #31  
Old 07-29-2010
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Some very interesting and well informed responses and I stand corrected.
This is something quite new to me-long range HF tranceivers.
Short range VHF I am very familiar with.
What really interests me however is what appears to be a misguided believe by many land based ham amateurs that modifying or at least using a modified radio to transmit on Marine Chanels is illegal not only when on land but even when at sea..This issue is often discussed on Ham sites both sides of the Atlantic.
There also appears to be here in the UK an impression created that using radios with such mods is illegal and certainly not acceptable.
Take a look at this UK based site
YachtCom - Marine Radio | Marine SSB MF HF VHF | Radio Licence | Marine Weather Bulletins | SSB email | Coastguards frequencies
I however do suspect that this site is sponsored by Icom.
Moding radios can be quite easy-many of the Yaesu tranceivers for example.
The early FT 757 has a wired in slide switch with later models having jumper leads;FT840s require no more than accessing part of the chanel programming.
However it appears to me that Icom make it difficult? because they would prefer you to use their more expensive dedicated marine tranceivers?
Having said all of this I cannot really imagine the US licencing authority or in my case the UK licencing authority Offcom dropping a member of their inspection team onto a yacht mid atlantic to see if you have the proper documentation!
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  #32  
Old 07-29-2010
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Various national authorities have varying regulations about requiring modifications to be difficult, or at least, inconvenient, in some radio service types. So the prudent manufacturer these days does not provide any obvious means of modifying a radio. The mods may be as simple as cutting a wire, removing a diode, or entering a "secret" program code, but they will be unapparent to the casual user, in order to meet regulations.

Since most radio equipment is sold to a global market these days and the same basic equipment must meet "all" regulations, changes in configuration are usually provided for, at some level. But not at an obvious one.

With regard to inspection teams, most governments do not waste time and money inspecting radios in any detail, unless complaints have been filed. Using a radio out of band may cause problems and get complaints filed, it has to be done with eyes open. And then there are countries like China, where simply entering the country with a radio transmitter that has not been licensed by the Chinese government, will get you arrested for espionage.

Knowing the rules can be important.
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  #33  
Old 07-30-2010
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Quote:
Originally Posted by ffiill
What really interests me however is what appears to be a misguided believe by many land based ham amateurs that modifying or at least using a modified radio to transmit on Marine Chanels is illegal not only when on land but even when at sea.
This may be "misguided" in the UK, but I can assure you that it is not for U.S. based hams. Anyone who is operating under the jurisdiction of the U.S. FCC is prohibited from using a non-type-certified radio (which would include modified ham radios) on marine channels except in an emergency.

Of course, there are American hams who make statements about this without qualifying them, and thereby implying that U.S. laws apply to everyone. Obviously that is not the case. One of the things about the internet, and forums like this, is that there are no borders, and you need to be conscious of who is telling you something and what their perspective is.

Bottom line, for hams operating under U.S. rules, it is illegal to use a modified ham radio on marine channels except in case of an emergency.
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  #34  
Old 08-19-2010
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So you are on a vessel licenced by your home country and with a marine call sign and you have a full ham licence and or a marine long range operators certificate.If you are using a modern radio with theoretical capability of generating a signal on any frequency unlike older xtal crystal controled radios what is the difference between using a ham radio or marine dedicated hf radio on marine frequencies? True you can tweak the frequency but equally you can store /programme in totally exact frequencies as on a marine preprogrammed hf radio.
As an aside for those who wonder what use the aeronautical HF has in this day and age of satellite communications I was recently talking to a long haul British Airways jumbo jet pilot who told me that particularly over Africa;Siberia ;the poles;transpacific etc that this remains their main means of communication with air traffic control etc which they have to tweak the same way as any of us amateurs!
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  #35  
Old 08-19-2010
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"what is the difference between using a ham radio or marine dedicated hf radio on marine frequencies?"
It isn't just frequencies. Marine HF radios typically are required to have lower levels of spurious emissions than ham radios, and they are "channelized" as opposed to the continuous tuning in ham radios. The differences are technical are just because the radios can use the same frequencies, does not mean they use them in the same way or with the same signal characteristics. Don't expect the bandwidths that are used, or allowed, to be the same either.

Yes, there are some ham radios that can meet or beat the marine specifications. There are many radios in this world and the regulations are there to ensure the one you use, won't interfere with other services or users. If you know enough about engineering to appreciate all the differences, you can probably break the rules without worrying. If you have to ask what the differences are--what "bandwidth" or "spurious emissions" means--you'd better stick to legally approved radios.

Last edited by hellosailor; 08-19-2010 at 04:13 PM.
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  #36  
Old 08-19-2010
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I have an ICOM 802 and it is great. I have used it on marine channels, ham channels and for email with a pactor.

When I was shopping around for radios I was told that the main reason ssb's have to be "type accepted" (i.e. each radio model has to be tested and approved for marine use by the FCC) is that there is far less signal splatter outside of the channels than on many ham radios. Yes, some ham radios can do as well or even better but they arent "type accepted" because it would cost the manufacturer too much to jump through the hoops for what is really a quite small market. So, the marine ssb market is dominated by the few manufacturers and the few models within each that have targeted the marine market. You can either spring for a new one of these or you can look for used ones which are far cheaper and can be found fairly easily.
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  #37  
Old 08-19-2010
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In addition to "type acceptance", there are real differences between ham radios and marine radios. The differences are not just in type acceptance, spectral purity (reduced "splatter"), and cost. Anyone who tells you different is either trying to make the case for spending less money, or they simply don't know what they're talking about.

Some of these differences include:

1. ability to operate effectively at lower input voltages (as often is the case on a sailboat with partially depleted batteries), without either severe FM-ing (distortion) or simply cutting out (as some ham radios do);

2. ease of operation....fewer controls, channelized operation, etc. This makes it far easier for a non-radio person to operate the radio in an emergency; and

3. marine radios tend to have superb audio quality, both on receive and on transmit. Typically, they easily surpass many/most ham rigs in this department.

Coupled with their spectral purity and frequency stability, this package of "features" makes most marine radios come in a cut above most ham radios for SSB operation on the marine bands.

However, they are typically less well suited for ham operation, because they :

1. have less frequency agility (yes, even the Icom M-802 isn't as easy to use on the ham bands);

2. lack many of the controls and features hams like to have (RF gain, CW keyers built-in, dual VFOs, notch filters, etc., etc.).

I sell and install both marine and ham radios on boats and have some 25 HF radios in stock at the moment...ham radios, marine radios, military radios, land mobile radios, aircraft radios. Many of these are connected and are operational during the workday...listening on ham, marine, aircraft HF frequencies. By the way, HF/SSB radio is not just the principal means of communication between ground controllers and long-distance aircraft in Africa as was mentioned above, but WORLDWIDE. Still.

I have two favorite radios which I operate daily on various ham and marine nets: a Kenwood TKM-707 marine SSB and a Yaesu FT-920 ham radio. The TKM-707 is a very, very simple radio....or so it would appear from the very few controls. But, it is a very sophisticated radio, with excellent performance. Alongside it is the FT-920 -- a very complicated radio. There are almost 80 knobs and buttons on the front panel, compared to 14 on the TKM-707, plus a keypad behind a little door.

They're both great radios. Both are technically capable of operating on the ham bands and the marine bands. Only one can be legally operated on the marine bands (the marine type-accepted TKM-707), provided you have the necessary marine station and operator licenses.

Both can be legally operated on the ham bands, provided you have a ham license.

As the previous post indicated, there's often not much difference in cost between ham and marine radios, particularly used ones. I have used ham and marine radios beginning at under $500. In any event, the difference in cost between marine and ham radios is a very small portion of the total cost of installation, counting the antenna tuner, the antenna system, the ground system, and the materials and labor for a proper installation aboard ship.

One strategy, which I use on my boat, is to install BOTH a ham rig and a marine rig. That way, you can have the best of all possible worlds, and be perfectly legal. And, if you choose quality used radios, you can do it for the cost of a single new marine SSB.

Here's a pic of my boat, with a Yaesu FT-900CAT ham radio on the left and a Yaesu System 600 marine radio on the right (the one with very few knobs). And, further to the right is a PTC-IIe SCS Pactor modem which will work with either radio. NavStn_0140

Bill

Last edited by btrayfors; 08-19-2010 at 09:52 PM.
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  #38  
Old 01-15-2011
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Some points not well covered so far:

The important difference between Marine and Ham radios?

All radios have banks of output filters to remove distortion products: A Ham radio has filters for the ham bands and marine radios have filters for the marine bands. If you use a ham radio on the marine bands, it is likely to cause interference due to the essential band-filters being missing.

Do the radios have audible differences?
Most definitely. Marine radios are designed for high audio quality: They have relative wide IF filters and low audio compression. Ham radios are designed for working DX. They usually have narrower filters and fairly aggressive audio processing.

The big difference however is that Marine radios do not have fine tune on their Transmit frequencies. The station which come up slightly off-frequency, then corrects their tuning on the next over is a dead giveaway. Even more so is one which needs to be re-tuned each over. These (and other) differences are obvious to a professional operator.

BTW, while it is legal to use any radio in an emergency, this does not excuse you for owning an unlicensed radio. If you say "I'd only use it in an emergency" you have just admitted to an offence. This particularly covers having unlicensed channels fitted.

Last edited by SparkyToo; 01-16-2011 at 01:09 AM.
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  #39  
Old 01-16-2011
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Sparky Too,

Good points on the filtering, audio quality, and fixed transmit frequencies in marine radios vs. ham radios. Yes, there really IS a difference.

Quote:
Originally Posted by SparkyToo View Post
......

BTW, while it is legal to use any radio in an emergency, this does not excuse you for owning an unlicensed radio. If you say "I'd only use it in an emergency" you have just admitted to an offence. This particularly covers having unlicensed channels fitted.
I don't get your point here, and suspect you may be in the UK or Australia or somewhere it's necessary to license a radio. This is NOT true in the U.S. Anyone can own a radio....no license required....just as anyone can own an airplane or a car. But to transmit on that radio (or fly that airplane or drive that car) without the proper license(s) is what will get you into trouble.

Bill
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  #40  
Old 01-16-2011
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Mostly it's not illegal to own an unlicensed radio, but to have it installed and ready to go is a whole different story. It's the "intent to use" which matters. But as you said Bill, it depends on the country.

Another point is the environmental standards. Part of the Acceptance Testing is a battery of environmental tests: Everything from extremes of Temperature, Vibration, Dust, Humidity, Corrosion, Water jets, Over-Voltage, Under-Voltage, High SWR, Lightning Strikes, ESD, Physical impact, etc. None of these apply to ham gear.

While a Marine radio should survive a decade or so at sea in a wet boat, the typical ham set will be a mass of corrosion internally after a year or so.

The higher price of marine gear is largely due to the higher standard of physical and electrical construction.

Last edited by SparkyToo; 01-16-2011 at 01:51 AM.
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