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Old 29-11-2011, 18:12   #31
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Re: Let the Hams in ?

If the issue here is about licensed hams operating ham radios on marine bands in an emergency I don't see what all the fuss is about. Yes, it does take more skill to operate a ham radio then it does to operate a marine SSB radio. But, if this is about unlicensed persons operating ham radios on the marine SSB bands then yes that would be a problem. There are just to many ways an unskilled operator can cause havoc with a ham radio.

From an equipment POV the biggest problems in using ham radios on marine SSB bands are frequency selection and drift. All of the commercial ham radios I have ever used allowed the frequency to be manually calibrated against WWV. It isn't all that hard but one does need to know what one is doing. The drift issue wasn't really a problem for the old Kenwood radios with their built-in TCXO, nor for the old ICOM radios that had the optional TCXO installed.

An example of how one might use a modified ham radio in an emergency occurred some years ago off the coast of Mexico. While monitoring the 40m Baja ham net a vessel called in believing that they were being attacked by pirates. The net control operator was a substitute and unprepared to handled this situation. As he continued to run the net I used my modified ICOM 751A to contact the USCG on 16 MHZ and alert them of this developing situation. The coasties brought a nearby USN ship up on frequency to establish contact with me. However, I was unable to hear the navy ship. I suggested we all move down to the 20m ham band. Their was a lot of interference on 20m so I moved everyone up to a clear frequency just above the 20m. Once the navy ship and I had good comm, I moved him down to the 40m Baja net frequency but using USB. This allowed me to talk to the navy ship on USB without interfering with the Baja net operating LSB on the same frequency. Thus, with the flip of a switch, I could work the Baja net on LSB and to pass traffic to the navy ship on USB. This whole process took less then 15 minutes to complete. BTW, it turned out that it wasn't pirates, but local fishermen trying to keep a yacht out of their nets.

I operated a modified ham radio on a frequency allocated for USCG maritime operations, I used that same radio to communicate with the USCG and USN on a frequency that was not allocated for use by any of us, and I used independent sideband modulation (ISB) which is not permitted by my license. All of this for what was not even a real emergency. The consequences for me where -- nothing, absolutely nothing!

However, I would be willing to bet that if a bunch of Yahoo's started interfering with communications on the marine SSB bands the FCC would come down hard on them.

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Old 29-11-2011, 19:37   #32
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Re: Let the Hams in ?

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Originally Posted by btrayfors View Post
Jim,

Happens all the time. That's why you often hear the various marine nets advising those who want to move off frequency to have a chat with another boat to use another band, e.g., move from 8mHz to 6mHz or 4mHz rather than just to another channel in the same band.

And, there are some irascible types who, in addition to using ham radios on the marine bands, insist on intentionally tuning off frequency "to make their voices sound deeper". This is not only flaunting the regulations but is grating on the nerves of experienced radio operators. You can't do this with a marine radio.

As Erik said, there may be some ham radios which could pass the more rigid marine type-acceptance standards, but not many. And, the 706 certainly isn't one of them....until the latest version it was a very dirty radio (you can't just cite one published spurious emission figure and see the whole picture).

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G'DAy Bill,

What you are describing here seems more an operator issue than a radio issue. And, the "moving to another band" is likely to avoid simple overload issues in a crowded anchorage rather than spurious emissions... an issue with both ham and marine radios. And your example of the irascible fellow is equally an operator issue (there are jerks everywhere!). Further, someone who is that anti-social would be likely to deliberately use the ham features of an 802 to do the same thing.

I agree that the marine radios make it somewhat more difficult for an inexperienced operator to stuff things up. And with the flood of newbie cruisers out here, the incidence of inexperienced folks is on the rise. Some take the trouble to learn good procedures and practices but many do not... it's pretty easy to tell them apart on the air!

But, I'm still looking for a documented case of a properly operated ham radio causing interference on the marine frequencies solely due to its design characteristics.

Oh, and finally, the lack of DSCC and such on private cruising yachts isn't a real issue to me, for some of us don't particularly want this and its related features. I won't argue about the desirability of these alleged safety features -- that's a personal decision -- but don't feel that the lack of them should rule out the use of ham radios. YMMV.

Anyhow, it's an interesting discussion.

Cheers and 73 de Jim N9GFT/VK4GFT
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Old 30-11-2011, 08:03   #33
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Re: Let the Hams in ?

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The drift issue wasn't really a problem for the old Kenwood radios with their built-in TCXO, nor for the old ICOM radios that had the optional TCXO installed.
Yet another big difference between marine and ham HF radio's. Marine radio's use OCXO's which are much more stable than a TCXO. There are many TCXO's available with some closely approaching the stability of an OCXO but I doubt there are many, if any, ham radio's that could really meet the frequency stability requirements of part 80 certification. The Icom 706 is certainly not one of them. The certification test requires that the output transmit frequency remain within ±10 cycles while the ambient temperature surrounding the unit is varied from -30°C to +60°C and the supply voltage is varied 85% to 115% of the normal supply.

While you may be able to use a ham radio on a marine channel without causing any problems or interference at all, your never going to be able to do it legally. The ham radio would not likely pass certification requirements and part 97 and part 80 are two entirely different services operating under different rules.

Eric
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Old 30-11-2011, 08:45   #34
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Re: Let the Hams in ?

Purely in regard to matters involving distress, I believe it is the law in just about any country you could name, that if you are in distress, you may use ANY MEANS to call for assistance. This would include tuning your ham HF radio, which you have of course lawfully used on ham bands only all this time, on a Marine HF frequency to call for assistance using MAYDAY.

This doesn't affect (insert your country's communications authority name here) rules on what type of radio gear is required for use by non technically qualified people such as yachties, in a genuine, life threatening emergency, you may use any means at your disposal to contact rescue, without fear of prosecution.

I suppose it's possible there might be some countries where this is not the case, but I don't know of one offhand. This does not cover day to day, routine or even somewhat urgent messages, so it won't help you there, but in a MAYDAY or PAN situation, I believe it's permitted, or more correctly, not forbidden.

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Old 30-11-2011, 08:52   #35
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Re: Let the Hams in ?

I have to agree with you. A good example is the Vertex 1700. It was designed as a multi chanel radio and marine use outside the US. It even had seperate buttons for 2182. The US version is advertized as land use and the dedicated 2182 button changed to channel up or down. The advertizing even shows it being used on off shore oil rigs where the 2182 button woulsd be an asset since the are technicly a vessel with the Coast Guard.
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Old 30-11-2011, 09:45   #36
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Re: Let the Hams in ?

The OP is off base. The specs cited are for in-band performance. The performance of a ham radio out-of-band (ham radio on marine frequencies) won't meet those specs.

The discussion on the getting certification is appropriate.

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I'm curious -- has anyone a documented case of use of a modern ham rig (the sort of thing that appears on our cruising yachts, where I've never seen a home-brew rig installed.
What do you expect in the way of documentation? I have personally experienced interference from ham radios used on marine frequencies for Sailmail in anchorages. Tracking down the source of interference isn't hard. Most of the cruisers where helpful and ultimately embarrassed to see the impact of their operation. What documentation would you like?
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Old 30-11-2011, 09:46   #37
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Re: Let the Hams in ?

Interesting. Nice looking rig, Iv'e always liked Yaesu products. So, the tight restrictions on frequency stability and spurious emissions of marine radio's is only a U.S. thing. The VX1700E has a ±1 ppm (after 60 min. @25° C) TCXO, thus the "marine" version is not available/legal in the US.

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Old 30-11-2011, 10:30   #38
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Re: Let the Hams in ?

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Yet another big difference between marine and ham HF radio's. Marine radio's use OCXO's which are much more stable than a TCXO. There are many TCXO's available with some closely approaching the stability of an OCXO but I doubt there are many, if any, ham radio's that could really meet the frequency stability requirements of part 80 certification. The Icom 706 is certainly not one of them. The certification test requires that the output transmit frequency remain within ±10 cycles while the ambient temperature surrounding the unit is varied from -30°C to +60°C and the supply voltage is varied 85% to 115% of the normal supply.

While you may be able to use a ham radio on a marine channel without causing any problems or interference at all, your never going to be able to do it legally. The ham radio would not likely pass certification requirements and part 97 and part 80 are two entirely different services operating under different rules.


Eric
Lets talk about WHY those frequency stability requirements exist--its a perfect example of a bureaucracy run amok, creating unnecessary costs which get passed on to us.

I'm not an expert, but in my experience the marine SSB's function (you could understand each other) if two radios are within 100 cycles of each other, so a more reasonable limit might be +/-50 cycles. If you use the built-in clarifier function you can probably get away with a 100 cycle drift on each radio. The Pactor mode already has an automatic frequency compensation scheme.

So WHY do you have to pay double the price for a marine radio to satisfy some bureaucrat??
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Old 30-11-2011, 12:20   #39
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Re: Let the Hams in ?

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.....
So WHY do you have to pay double the price for a marine radio to satisfy some bureaucrat??
You don't. And, in point of fact, the differential cost between a modern ham radio and a new marine radio isn't that great.

The IC-7000, successor to the most popular ham rig ever -- the IC-706MKIIG -- costs within a couple hundred dollars the same as, e.g., an Icom M700Pro. An Icom M710 costs a few hundred more. The 802 costs about $400-500 more.

But wait: the cost of the radio itself is only part of the true cost. Both types of radios need a good automatic tuner. The best one out there for the past 20+ years is the SG-230. It still costs $499.95 new. The lesser capable but still very good automatic tuners by Icom (the AT140 and AT130) cost about the same, and about $100 more if you include the mandatory control cable (the SG-230 doesn't require a control cable, and can be used with ANY HF radio).

Then, there's the cost of the antenna and ground system, of parts and supplies needed for a good installation, and the cost for an installer if one is required/desired.

All told, the price differential between ham and marine SSBs complete systems is on the order of 10% or less.

With used equipment, prices are even closer. You can buy a rock solid M710 used from the Icom repair center in SC for about $600. Any good ham radio appropriate for use on a boat is going to cost in that neighborhood, too.

By the way, the standards are not set up to appease bureaucrats. They are part of an international schema of telecommunications specifications and regulations which are codified in international law, and which are the subject of international treaties. Individual countries which are signatories to those agreements (like the U.S.) have only limited scope to depart from the standards, and can do so only as it pertains to their own territorial waters.

I really don't understand all the falderall. The regulations are in place for good reason, and the various services occupying the HF radio spectrum all work pretty well: marine, aircraft, amateur, military, transportation/land mobile, point-to-point, etc., etc.

Why rock the boat? Surely there are other things of greater interest and threat to the cruising world.....like, maybe, anchoring rights?

Bill
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Old 30-11-2011, 12:35   #40
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Re: Let the Hams in ?

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By the way, the standards are not set up to appease bureaucrats. They are part of an international schema of telecommunications specifications and regulations which are codified in international law, and which are the subject of international treaties.
I'm not convinced of that (the international standards part). How is it that the VX1700 (marine version) cannot be certified for use in the US yet can be in Europe? Apparently, FCC technical requirements are different than those of European nations.

Eric
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Old 30-11-2011, 13:41   #41
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Re: Let the Hams in ?

I can understand people using a ham radio on marine channels while cruising, but I can also see the problem of hf radios overpowering marine radios and not hearing critical calls. I know marine radios can be doctored to transmit at 100 watts, but aren't they legally supposed to be limited to 25 watts? If you dial back the output of an hf radio to 25 watts for other than emergency, and you stay in frequency, I'd agree with allowing it. (I'm also a ham)
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Old 30-11-2011, 14:30   #42
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Re: Let the Hams in ?

I'm with Paul on this. I think some frequencies should be designated for boaters only and perhaps let the HAM's in on some of the other marine frequencies. Seems this would be a nice compromise.
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Old 30-11-2011, 14:49   #43
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Re: Let the Hams in ?

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I know marine radios can be doctored to transmit at 100 watts, but aren't they legally supposed to be limited to 25 watts? If you dial back the output of an hf radio to 25 watts for other than emergency, and you stay in frequency, I'd agree with allowing it. (I'm also a ham)
You must be confusing marine VHF-FM radio's with marine HF. Marine VHF ship radio's are limited to 25 watts and cannot be "doctored" to transmit at 100 watts. They are far removed in frequency from HF frequencies. Marine HF's are typically 150 watts PEP on SSB while ham HF SSB radio's are typically 100 watts PEP.

It's a nice debate, but ham radio's will never be certified for use on marine channels.

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Old 30-11-2011, 15:12   #44
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Re: Let the Hams in ?

I know...err...somone...... who did it a lot with no issues. no one can really tell. just be sure to program the correct duplex frequencies.
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Old 30-11-2011, 18:12   #45
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Re: Let the Hams in ?

Thanks to everyone for your comments and thoughts. This is turning into a great winter project.

It all seems to boil down to two issues– what is the real frequency stability of a ham radio and what could reasonably be expected of the FCC in terms of practical implementation. I suspect the latter is nil.

For the techies in the crowd there is no shortage of documentation on the frequency stability issue. Results are all over the board (some very scary) and largely dependent on how much effort the individual ham put into the issue (and modifying their radio). ARRL (mothership of hams) has some really interesting test results here:

ARRL Frequency Measurement Test Results

These are real world tests in that they are measured over the airways. These are laboratory results in that the operators took extreme measure to improve stability – software control, etc. High praise to the HAM community that they are concerned enough with the subject to host monthly contests. It should be noted, the best in the group achieved PPM readings of less than 1 HZ – 10 times the performance of the 802 minimum spec. Most participants equaled the 802’s spec. There are of course no comparable results for marine HF radios in this test.

I will be spending the next few months learning to test my own rig(s) and will publish those results when available. It will be interesting to see what could be reasonably be expected of a cruising sailor. I suspect quite good results but we’ll see where the numbers fall.
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