Home |
Search |
Today's Posts |
#11
posted to rec.boats.electronics,rec.boats.cruising
|
|||
|
|||
AIS hardware and software
On Sep 16, 2:57 pm, Dick Locke wrote:
I'm trying to figure out the best way to install an AIS system in our cruising sailboat. It's largely used coastally off Mexico with occasional longer passages of a few hundred miles. Night passages are common. Hardware questions: There seem to be two price points..single channel, serial only for about $190 from Milltech or dual channel USB capable from Safe Passage for around $800. I'm thinking single channel is adequate but I my sole serial port is occupied by the GPS and I've had problems in the past with the serial/usb adapters. Anyone know of a single channel USB output receiver? I have an unused "emergency" VHF antenna on a pole about 12 feet above the water. I could use that for the AIS or I could use a splitter on the masthead antenna. I'm not inclined to do anything to reduce VHF reception. Can someone tell me the formula for VHF "line of sight" distance? Software questions I'm currently using MAptech Offshore Navigator which doesn't have AIS support. I'd have to upgrade to their newer system or else buy another. Fugawi seems attractive. I have a whole bunch of Maptech formatted charts but Fugawi seems to be able to handle these OK. In either case, I would lose my "tracks" of past passages. Those are especially handy off the Mexican coast because the charts are hand drawn in 1888 or so and the shore is a few miles further east than the charts show...except when it isn't. Finding a way into an anchorage or around a rock once during daylight gives me a track I can follow next time. Maptech suggests converting tracks to routes, but I haven't looked into that yet. Does anyone know how to get the track files out of Maptech's program? If they have lat longs I might be able to bring them into the new program. I also think I could keep the old Maptech program and switch it on when following a past track is essential. I wonder if I could run both simultaneously and bring the old program on screen.when I need it. Any comments or advice? I'm not at the boat now so can't experiment very much. Thanks Dick Locke S/V Tanoshii Full disclosu I have an ax to grind. I am with SeaCAS. We sell dual- band receivers. Our receivers used to cost about $800 but are now on sale for $499 and we include a USB power/data cable which makes connection to a PC or Mac very easy. Also our connectors are watertight and we offer optional "Direct-Connect" cable for FURUNO and Raymarine. To circumvent Raymarine's limitation of a single NMEA port on their C and E series we offer a very capable Multiplexer for $330 (see http://www.seacas.com/oscomm/product...roducts_id=47). I maintain that single band receivers are too slow to be used for collision avoidance. AIS information is transmitted alternating between VHF Channel 87B and 88B. Single band recievers receive only half of the information. Their update rate is twice what it should be. In a close quarters crossing situation you want the best available information to help you decide how to get out of a big ship's way. You may have to wait as long as 12 minutes to find out a ships name so you can hail it on VHF to make assing arrangements because the name (along with other statis and voyage information) is sent our every 6 minutes and it too alternates between 87B and 88B. Fred Pot SeaCAS, LLC |
#12
posted to rec.boats.electronics,rec.boats.cruising
|
|||
|
|||
AIS hardware and software
He didn't say "USB hub". He said "serial/usb adapters". I've had problems with them -- the
first one I got didn't support Break (which is not a character, but rather pulling the computer's Data In line low (or was it high) for an extended period of time (and of course the first thing the box I bought it to use with needed was ..... a break, to wake it up. Some of them don't support some of the other obscure corners of the serial port protocol. "Larry" wrote in message ... Meindert Sprang wrote: "Dick Locke" wrote in message ... There seem to be two price points..single channel, serial only for about $190 from Milltech or dual channel USB capable from Safe Passage for around $800. I'm thinking single channel is adequate but I my sole serial port is occupied by the GPS and I've had problems in the past with the serial/usb adapters. Anyone know of a single channel USB output receiver? You could use a MiniPlex-Lite, a small NMEA multiplexer with a USB interface and one high speed input for your AIS receiver next to two normal NMEA inputs (GPS, etc). And it comes without the typical problems found with serial/usb adapters. This box simply works. Meindert www.shipmodul.com Meindert, No flame intended, really! What are the typical problems with USB hubs? Thanks! -- Larry rapp at lmr dot com |
#13
posted to rec.boats.electronics,rec.boats.cruising
|
|||
|
|||
AIS hardware and software
Fred Pot wrote in
ups.com: On Sep 16, 2:57 pm, Dick Locke wrote: I'm trying to figure out the best way to install an AIS system in our cruising sailboat. It's largely used coastally off Mexico with occasional longer passages of a few hundred miles. Night passages are common. Hardware questions: There seem to be two price points..single channel, serial only for about $190 from Milltech or dual channel USB capable from Safe Passage for around $800. I'm thinking single channel is adequate but I my sole serial port is occupied by the GPS and I've had problems in the past with the serial/usb adapters. Anyone know of a single channel USB output receiver? I have an unused "emergency" VHF antenna on a pole about 12 feet above the water. I could use that for the AIS or I could use a splitter on the masthead antenna. I'm not inclined to do anything to reduce VHF reception. Can someone tell me the formula for VHF "line of sight" distance? Software questions I'm currently using MAptech Offshore Navigator which doesn't have AIS support. I'd have to upgrade to their newer system or else buy another. Fugawi seems attractive. I have a whole bunch of Maptech formatted charts but Fugawi seems to be able to handle these OK. In either case, I would lose my "tracks" of past passages. Those are especially handy off the Mexican coast because the charts are hand drawn in 1888 or so and the shore is a few miles further east than the charts show...except when it isn't. Finding a way into an anchorage or around a rock once during daylight gives me a track I can follow next time. Maptech suggests converting tracks to routes, but I haven't looked into that yet. Does anyone know how to get the track files out of Maptech's program? If they have lat longs I might be able to bring them into the new program. I also think I could keep the old Maptech program and switch it on when following a past track is essential. I wonder if I could run both simultaneously and bring the old program on screen.when I need it. Any comments or advice? I'm not at the boat now so can't experiment very much. Thanks Dick Locke S/V Tanoshii Full disclosu I have an ax to grind. I am with SeaCAS. We sell dual- band receivers. Our receivers used to cost about $800 but are now on sale for $499 and we include a USB power/data cable which makes connection to a PC or Mac very easy. Also our connectors are watertight and we offer optional "Direct-Connect" cable for FURUNO and Raymarine. To circumvent Raymarine's limitation of a single NMEA port on their C and E series we offer a very capable Multiplexer for $330 (see http://www.seacas.com/oscomm/product...3&products_id= 47). I maintain that single band receivers are too slow to be used for collision avoidance. AIS information is transmitted alternating between VHF Channel 87B and 88B. Single band recievers receive only half of the information. Their update rate is twice what it should be. In a close quarters crossing situation you want the best available information to help you decide how to get out of a big ship's way. You may have to wait as long as 12 minutes to find out a ships name so you can hail it on VHF to make assing arrangements because the name (along with other statis and voyage information) is sent our every 6 minutes and it too alternates between 87B and 88B. Fred Pot SeaCAS, LLC I have a single band Miltech receiver and agree that perhaps there's an issue with not receiving the name of the ship for 12 minutes instead of 6 minutes. But who cares? Course data is transmitted every few seconds. Until recently we only had radar and never knew the name of the ship. With AIS we have a much better chance of knowing lots of details and knowing them well before they get WAY too close. While I'd love to know the name of the vessel that I'm on a collision course with, I would much rather know in advance if and when we were going to collide. I get all of that with single band AIS. What I really want is a reasonably priced AIS transponder. No offense, but this is not rocket science. Basically all that you need to do is transmit position and course information and occasionally your ship info. I suspect that you'll see reasonably priced units on the market in a short period of time. -- Geoff www.GeoffSchultz.org |
#14
posted to rec.boats.electronics,rec.boats.cruising
|
|||
|
|||
AIS hardware and software
"Larry" wrote in message
... Meindert, No flame intended, really! What are the typical problems with USB hubs? Thanks! I suspect you mean serial/usb converters? Many of them don't have an internal serial number so the created com port changes when you plug it into a different USB port. All of them support the M$ Plug & Play support for serial ports which means Windows thinks your GPS is a mouse. Many of them don't work as supplied, wrong drivers and that sort of stuff. If you really meant USB hubs, then I don't know of any problems with them apart from being able to be powered from 12V or 24V. Meindert |
#15
posted to rec.boats.electronics,rec.boats.cruising
|
|||
|
|||
AIS hardware and software
On Tue, 18 Sep 2007 09:18:15 +0200, "Meindert Sprang"
wrote: "Larry" wrote in message ... Meindert, No flame intended, really! What are the typical problems with USB hubs? Thanks! I suspect you mean serial/usb converters? Many of them don't have an internal serial number so the created com port changes when you plug it into a different USB port. All of them support the M$ Plug & Play support for serial ports which means Windows thinks your GPS is a mouse. Many of them don't work as supplied, wrong drivers and that sort of stuff. If you really meant USB hubs, then I don't know of any problems with them apart from being able to be powered from 12V or 24V. Meindert Amen to all that. My computer also thinks my serial-ported GPS is a mouse if I boot the computer up with the GPS on. (I'm 99% sure it's serial ported, if I was anywhere near the boat I'd go double-check before sending this...) I'm running XP home, original basic edition with no updates because the boat computer isn't allowed to get on the Intenet. I guess it's time to buy an update disc. |
Reply |
|
Thread Tools | Search this Thread |
Display Modes | |
|
|