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#61
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#62
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Not at all,
Unless the US has secured world domination, the US governement has no legal right to inspect any vessel other than their own outside US waters. A boarding of say, a Danish sailing boat in the mid Atlantic is legaly an occupation of foreign territory. Nor would a VHF-FM radio be any good 3000 km from the nearest shore unless there were another VHF enabled vessel within about 15 - 20 nm. Boarding vessels from rouge governements in the name of terror protection is a questionable defence, in particular when no conterfeit goods are found. But it's probably hard to argue this looking straight into the wrong end of a gun. ottar Sorry fot the typo's, right hand is in a splint. A VHF-FM license is no longer required for boats inside US waters, unless they are commercial. They are still required when outside US waters. |
#63
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On Fri, 04 Mar 2005 17:57:50 +0100, Ottar
wrote: Not at all, Unless the US has secured world domination, the US governement has no legal right to inspect any vessel other than their own outside US waters. A boarding of say, a Danish sailing boat in the mid Atlantic is legaly an occupation of foreign territory. ================================= Not really. Senior coast guard officials have explained to me that the US government has treaties with almost all countries that allow international boarding and search of any vessel suspected of possible criminal activity. Some of these treaties require explicit prior approval but supposedly it is routinely granted. Vessels of unknown flag are also boarded on the high seas if they are suspect. |
#64
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In article iAUVd.43935$xt.17799@fed1read07,
"William Andersen" wrote: No matter what you get, if you're going to work from a boat I think you're required to also have a VHF-FM radio. Seems to me I read it in Chapman's. thuss" wrote in message oups.com... I would go to your local HAM store and talk to them about gear. There are a lot of choices out there from tiny mobile QRP type rigs to larger base stations that will all work in your boat or RV. I would start out by getting a rig setup that's capable of doing packet and then adding a pactor or similar into the mix later. -Todd Well not exactly......... Any uninspected US Flagged vessel is NOT required to have any radio aboard, unless: 1. It is longer than 20 Meters 2. It is towing 3. It is required by The Fishing Vessel Safety Act..... 4. It is a Small Passenger Vessel with more than six passengers aboard. (I guess that would make it Inspected) If a Marine MF/HF radio is fitted then a Marine VHF Radio MUST be fitted as well, but if a Ham Radio is fitted there is no requirement for a Marine VHF Radio to be fitted. Bruce in alaska -- add a 2 before @ |
#65
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In article .com,
"Leonard" wrote: Sorry fot the typo's, right hand is in a splint. A VHF-FM license is no longer required for boats inside US waters, unless they are commercial. They are still required when outside US waters. Actually not quite accurate. Licensing is only required if you communicate with a Coast Station of another country. If you just sail out past the 20 mile Limit, but don't enter another countries waters, or communicate with another countries Coast Stations, you are still covered by the Blanket US License if your vessel is US flagged. This is, however, a very minor distinction. Bruce in alaska -- add a 2 before @ |
#66
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Hey Larry,
A small clarification. There are two types of AMTOR: ARQ and FEC. The ARQ mode does involve error correction, but the FEC (which is Forward Error Correction, not Full Error Correction) does NOT. AMTOR B, which is FEC AMTOR, simply sends each character twice. If that doesn't do it, the character is lost or received erroneously. 73, Chuck Larry W4CSC wrote: "thuss" wrote in oups.com: Larry, I was under the impression that pactor II or III were far more reliable and allowed faster transmission rates thank PSK31, is that incorrect? Thanks, Todd Packet, Pactor, AMTOR (or its commercial cousing SITOR) are all acknowledged modes. You send X characters to me....I add up the values and send you an ack or nack to either resend more characters of the next group or resend the old group again until I get it right. It's full error correction. That's what the transmitter and receiver are doing all that switching back and forth for. This is just great for binary file transfers or something that just HAS to be perfect. But, for text send/receive, it's not really necessary. However, for email the header must be perfect or it isn't going to happen. So, yes, Pactor, the chosen mode of the emailers, is necessary. Now, if we were to set the same radios on 10 watts in Pactor and PSK31, you'd first notice that PSK31 just keeps plodding along as fast as you can type. No acknowledgement packets are sent or desirable. The transmitter stays on the air until your fingers tire or you run out of things to type about. Then, it's the other guy's turn and you keep receiving him.... IN a packet switched type system, no matter what the name of the scheme, when things go wrong, they go VERY wrong, resending the same "packet" or "group" of characters over and over and over until the proper response is received from the other end. In good conditions, it may be faster than PSK31 IF you are a fast typist or are sending a text file. In bad conditions, it amounts to ZERO as the conditions are too bad for perfect copy on the other end. Some of the schemes reduced the number of characters per packet to just a few letters before the ack attempt. This, of course, reduces the transmit times and makes for poor throughput. Sitor/Amtor does this and is painfully slow. Unlike Pactor or the others, PSK31 is NOT an error-correcting digital mode designed to transfer documents and binaries perfectly. But, as it costs you NOTHING to play with, only the price of a cable from your headphone jack on the radio to the line input of your soundcard and the download time of a free software, you have nothing to lose in trying it. The softwares have an audio spectrum display so you can pick which of the little narrow PSK tracks for the software to decode and display. I invite you to pick the faintest, tiniest, weakest track on the display to test PSK31's capabilities. Pick one that fades in and out so you can see at what point the errors start in the decoded display. On the HF bands, PSK operators all hang out in about 1 SSB bandwidth, most notably 14.070 Mhz carrier frequency USB. That's where you'll find the most stations to test out your system. I'd like to make another note while spewing my nonsense. DO NOT BUY THE VARIOUS INTERFACE BOXES SOLD SO YOUR COMPUTER CAN KEY UP YOUR TRANSMITTER! I've never had one! I'm using plain-vanilla, but nice ham radio equipment that ALREADY has a VOX (voice operated transmit) circuit built into its microphone electronics. PSK31 has no need of rapid on-off switching, like pactor/packet/amtor/etc. If you simply switch the transmitter on manually then click the XMIT button on the software to start the tone generation, that works fine. VOX automates it as the transmitter will key up when it hears the tone. Set the VOX delay to zero as you want the transmitter to drop back to receive when the tone stops. Nothing could be easier. Hook a simple 1K ohm volume control into the cable between the computer's audio output (line out if you have it) and the transceiver's microphone input wherever you can hook to it, even by unplugging the mic. COMPUTER AUDIO OUTPUT---------|CW end / \ (wiper - center pin) /--------------------MIC INPUT of radio 1K Pot \ / GROUND CCW end There's your total electronic circuit to use PSK31.....cheap! Any old volume control pot between 500 ohms and 50K ohms works. This only reduces the volume of the tones as mic inputs are low level, also reducing hum by turning up the output of the computer and turning down this pot towards ground to compensate. Just barely off ground is where most dynamic mic circuits like it....just enough to get audio to key the VOX and modulate the mic input. Audio to the computer is much less critical. That and a copy of your choice in PSK31 software is all you need....and total fun on very low power (10-20 watts max!), which makes the PSK bands so many people can use it without interfering with each other. Great fun, even if it won't email home. Home needs to get off their asses and get their HAM LICENSES we've made SO easy to get, now! Another note to ANY DIGITAL MODE......DO NOT FORGET TO UNPLUG THE MICROPHONE! FCC TAKES A REALLY DIM VIEW WHEN IT HEARS AUDIO IN THE BACKGROUND OF ANY DIGITAL MODE because whenever the transmitter is on, it's transmitting that TV behind you on SSB while your digital tones are also on the air! Some radios with "data inputs" for the tones DON'T disconnect the microphone audio just because you plugged something into it. Test yours carefully.... |
#67
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If you plan to dock in a foreign port (e.g., Canada or the Bahamas) or if you communicate with foreign coast or ship stations, you must have a RESTRICTED RADIOTELEPHONE OPERATOR PERMIT (sometimes referred to by boaters as an "individual license") in addition to your ship radio station license. Section IV outlines the procedure for obtaining a permit. However, if (1) you merely plan to sail in domestic or international waters without docking in any foreign ports and without communicating with foreign coast stations, and (2) your radio operates only on VHF frequencies, you do not need an operator permit. NOTE: A ship radio station license authorizes radio equipment aboard a ship, while the restricted radiotelephone operator permit authorizes a specific person to communicate with foreign stations or use certain radio equipment (e.g., MF/HF single sideband radio or satellite radio). Above copied from FCC website. Bruce in Alaska wrote: In article .com, "Leonard" wrote: Sorry fot the typo's, right hand is in a splint. A VHF-FM license is no longer required for boats inside US waters, unless they are commercial. They are still required when outside US waters. Actually not quite accurate. Licensing is only required if you communicate with a Coast Station of another country. If you just sail out past the 20 mile Limit, but don't enter another countries waters, or communicate with another countries Coast Stations, you are still covered by the Blanket US License if your vessel is US flagged. This is, however, a very minor distinction. Bruce in alaska |
#68
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Wayne.B wrote:
On Fri, 04 Mar 2005 17:57:50 +0100, Ottar wrote: Not at all, Unless the US has secured world domination, the US governement has no legal right to inspect any vessel other than their own outside US waters. A boarding of say, a Danish sailing boat in the mid Atlantic is legaly an occupation of foreign territory. ================================= Not really. Senior coast guard officials have explained to me that the US government has treaties with almost all countries that allow international boarding and search of any vessel suspected of possible criminal activity. Some of these treaties require explicit prior approval but supposedly it is routinely granted. Vessels of unknown flag are also boarded on the high seas if they are suspect. Closer, I'm sure the US has bilateral agreements with other nations facilitating such boardings. If your coast guard or navy wish to board such a vessel, they are probably checking the list if there are other requirements before doing so. Vessels of unknown flag, that is none recognized by UN or IMO are not protected by any authorative governement. They are the underdogs of the seas and treated at will by any navy in the area. Such ships could just as well fly the jolly rogers. ottar |
#69
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chuck wrote in :
Hey Larry, A small clarification. There are two types of AMTOR: ARQ and FEC. The ARQ mode does involve error correction, but the FEC (which is Forward Error Correction, not Full Error Correction) does NOT. AMTOR B, which is FEC AMTOR, simply sends each character twice. If that doesn't do it, the character is lost or received erroneously. 73, Chuck Yeah, they wouldn't use FEC with email as the header would be trashed..... |
#70
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On Sun, 06 Mar 2005 22:31:29 -0500, Larry W4CSC
wrote: chuck wrote in : Hey Larry, A small clarification. There are two types of AMTOR: ARQ and FEC. The ARQ mode does involve error correction, but the FEC (which is Forward Error Correction, not Full Error Correction) does NOT. AMTOR B, which is FEC AMTOR, simply sends each character twice. If that doesn't do it, the character is lost or received erroneously. 73, Chuck Yeah, they wouldn't use FEC with email as the header would be trashed..... =========================== Larry, are there any PSK31 stations that function as packet gateways? |
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