Electronics

(Instruments, NMEA, WxFax, Skype, TV antenna)

from the

Tayana-list

Perhaps someone out there can help me with a problem I am having with linking various instruments that are all supposed to be NMEA. Perhaps I am missing something, and someone out there can help clarify this. I am trying to couple:

1) Standard Horizon Wind Instrument (Wind direction, speed, angle, and when hooked to their Speed/log, True and Apparent wind) WS150

2) Standard Horizon Speed SL150

3) Standard Horizon Depth DS150

4) Garmin 130 GPS

5) Standard Horizon VHF 1260 with DSC and display of Lat/Long

6) Navico YP500 Autopilot

7) Occasionally Laptop Computer, running MarineMap 3.2

In order to merge the various inputs from the Wind, Speed, Depth, and GPS, they run to a NoLand Multiplexer N183-41. It can support 4 inputs, but Input #2 is unreliable if running in RS422 due to a timing conflict. The N183-41 can be configured to output either to their RS232 or to their RS422 ports. However, in order to use the RS422 output, the TX and RX lines on the RS232 have to be jumpered. The RS232 can support a MAXIMUM of 2 devices. The RS422 port can support a maximum of 4 devices.

a) When I send the GPS directly to the VHF, it correctly displays the Lat/Long on the VHF

b) When the AWI is sent directly to the Autopilot, it operates briefly, then drops the signal.

c) When GPS is sent directly to the Autopilot, I believe that it also operates correctly in Steer to Waypoint mode

d) The Garmin cannot accept and retransmit the AWI, SL and DS inputs. (Most unfortunate, as it would eliminate the need for the $180 for the Multiplexer).

e) All the instruments (GPS, WS, DS & SL) appear to be transmitting correctly, based on LED monitoring of their outputs. However, lacking an oscilloscope on the boat, I could only measure voltages with a digital voltmeter in Store and Hold Max Value mode. The VHF output was about 3+ volts. The Wind Indicator fluctuated between 0.7 and 1.45 volts. The DS and SL were consistently below 1 Volt. A phone call to Standard Horizon indicated that the output of the WS, DS and SL are of 50 microsecs duration and unlikely to be accurately measured with a digital voltmeter. (Is this part of the NMEA standard?)

When inputs are all fed to the NoLand Multiplexer, LED indicates activity on the RS232 port. When output is fed from RS232 to only VHF, it correctly displays the Lat/Long. When output is fed from RS232 to only Autopilot, it correctly operates with either wind or GPS inputs.

HOWEVER - if RS232 is connected to BOTH Autopilot and VHF, then the VHF no longer receives a stable Lat/Long reading. It shows briefly, then drops the Lat/Long. But the Autopilot works correctly in all modes. In order to show Lat/Long on the VHF, and still allow the Autopilot to work correctly, I had to hook the VHF directly to the GPS output, and the Autopilot to the RS232. Am I correct in assuming that the required input voltages/current requirements of the VHF and Autopilot overloaded the output ability of the NoLand RS232?

I then tried an alternate strategy. I jumpered the TX-RX ports on the Multiplexer, as suggested by NoLand, in order to activate the RS422 output. The GPS could now report to the VHF, but the Autopilot failed to indicate that it was getting either the Wind or GPS inputs. The NoLand manual and their Website Instructions are in conflict regarding which of the TLK ports are A and which are B (for Hi/Lo?). I tested it both ways, and still couldn't get the Autopilot to hear the inputs over the RS422 output.

So? Different questions about each instrument, and my inability to get a clear solution to the problems.

1) Can the Autopilot YP500 read RS422?

2) Why can't the VHF read the RS232 when the Autopilot is simultaneously able to read it?

3) Given all these complexities, is there any way that I can get all these instruments to talk to each other, and still be able to control them with my computer? (I want to be able to use my Navigation Software to control the Autopilot on occasion.)

4) How do I now wire in the data output line from the computer to the Garmin? (Garmin makes things more difficult, as they have their own unpublished data protocol for Up / Downloads, separate of their open standard NMEA outputs.)

Sorry for the lengthy communiqué, but I am confused and need help.

regards, Harvey May 2002

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Wow, Harvey! What a setup! I tried a NoLand Multiplexer once but then found out that my Simrad IS-15 instrument setup would multiplex them all. I run dual GPS input/ outputs with a separate DGPS receiver, LORAN, autopilot input, and dual computer output/input at any of two stations, plus data output/input from my five IS-15 instruments. I had to build an NMEA distribution box to help with the manual routing of signals (which of the two GPS or computer outputs controls the autopilot, GPS download/upload signal routing, and which GPS provides data for the instrument Nav display).

The folks at NoLand are probably the best to help with your compatibility problem. As far as GPS input for the radio, it might be easiest to buy someone's second-hand GPS and dedicate it to the radio.

The autopilot needs NMEA sentences BWC, APA, & APB to follow your GPS or computer output and to generate X-Track error and provide most of the standard navigation displays.

I don't know about MarineMap's NMEA input/output/logging capabilities since I use the CAP'N. My software will log Time, Date, Lat/Long, COG, SOG, Compass heading, Depth, True and relative wind direction and speed, Water temp, and speed thru water. The computer-to-GPS hookup just takes 3 wires although 4 are sometimes used MarineMap and Garmin should have that info.

Getting all NMEA 0183 devices to talk to each other is a daunting challenge - especially when different brands are involved. In fact, it may be doggone near impossible. Now, NMEA has established a new standard – NMEA 2000. Only problem is that it's not out yet nor used by electronic manufacturers. And it is two years late already!

Good luck, Harvey! You have your hands full!

Wayne Strausbaugh V-42 C/C RESTLESS May 2002

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Wayne,

Many thanks for your comments (and sympathy!). I went back down again today, and actually managed to run the autopilot under all three alternate modes while out in the ocean: Steer to Compass, Steer to Waypoint (via GPS) and Steer to Wind. The VHF dutifully displayed our Lat/Long, so if we drown while sending out a distress call on our new DSC supporting VHF, (properly registered with our MMSI Id#) the Coast Guard will be able to notify our last-of-kin - assuming that they finally are given enough funds by Congress to allow them to purchase last years outdated VHF at West Marine with discount prices.

Until now, we had only used the Steer to Compass mode, so this was a great day for those of us illiterate in the ways of TTL, NMEA, RS-232, RS 422, etc. Still not certain about how I will link the computer to all this, but at the end of the day, I found a DB9 serial wire, dissected out the wires leading to each pin, tracked down the Rx, Tx and ground lines, and wired them into the boat control circuit. I then hooked it to the laptop computer, ran Hyperterminal.exe, and Shazam!!! There was all the data, streaming

across my computer screen, faster than I could read it. Thank heavens I remembered the old commands from my early generation LINC-8, PDP-11, and even early DOS. A quick flash of the fingers with a Ctrl+S, and the screen stopped scrolling, and I could actually make sense of some of the data displayed (such as the GPS coordinates). Perhaps tomorrow I can even manage to get Marine Map to hear the deep throated rustlings of the musical sounds of NMEA and convert that to confirming that I am at rest in my slip in San Diego - although that may be expecting far too much!.

As we were heading home from the ocean under complete control of our wind instruments, GPS and autopilot, I felt this overwhelming nostalgia for just sailing - yep, I mean with all that crap turned off, and my own meaty hands on the steering wheel. So I actually turned off the autopilot, ignored the GPS, stared at the Windex rather than the AWI, and sailed to the breeze on my neck. Ya know what? It actually felt good. I think I'll reserve all that automatic stuff for when we have to cover distance, and sailing in lousy weather, and revert to hands on sailing when I want to remember why I'm out there.

regards, Harvey May 2002

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I am currently looking at purchasing new instruments for my boat. The Nexus instrument system looks good for the money as well as the Standard Horizon stuff. Has anyone these instruments installed how are they in terms of performance, customer service and interfacing with other electronics. I am starting from pretty much scratch and any suggestion to starting up with the right gear would be appreciated. Money is a
concern I can't afford the best in all but am looking more toward decent instruments that give me a good bang for my buck. I was also looking at the Standard Horizon chartplotters. Any thoughts on the ideal "budget system" would be appreciated.

Phill T-37 #101" gone with the Wind" May 2002

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Phill,
After one month of having this all installed, we are happy with it. Raymarine was easy to deal with and their gear is on a lot of boats. The people that I have met with ST60 gear seem to be happy. Those with the older ST50 stuff not so.

I have heard good things about the Nexus and Standard Horizon instruments. I would steer clear of Signet. We had the depth and knot on our last boat and they sucked - sorry.

Good luck, Richard Brown M R Destiny May 2002
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Phill,
I definitely second Richard’s statement about Signet. It is lousy stuff, very expensive to repair, and their transducers for speed are flimsy. ST60 is great stuff, but I think it is much more expensive than Standard Horizon. Other people we know who have the ST60 in conjunction with RayMarine Radar are absolutely wild about it.

regards, Harvey May 2002
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Phill

Thanks all for the feedback. I am really tempted to go with the Nexus stuff although I have no aversion to the other brands. I am a little concerned about the length of the transducers +-3.5".

Did any of you install the transducers, eg, cut holes etc? I want to be sure the transducers will fit as the only other option from Nexus is a long multi-transducer that pushes the price up considerably. I may as well then go on to the ST60 stuff from Raymarine. So does anyone know what the hull thickness is approx at the sheer were the instruments would be mounted. Hey, thanks for the detailed feedback.

Phill May 2002

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The hull was only about 1/2 to 3/4 inches thick immediately adjacent to the keel about where the mast is, plus another 5/8" for the backing wood thing (proper name eludes me). I can't imagine that you would need a longer transducer.

Richard Brown May 2002
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Phill,
I just finished installing the Standard Horizon Wind, Depth and Speed instruments. I understand the Nexus instruments are very good. I chose the series Standard Horizon /Vertex 150 instruments based on recommendations of performance as well as price. I was able to use the older Depth Sounder transducer with the new Standard Horizon DS150 without any problem, and it seems accurate. I installed a new speedo transducer. The new transducers come with a flap valve that reduces the amount of water than enters the bilge when you remove the speed transducer to clean it.

Don't buy older models on clearance, as they may not be fully compliant with NMEA 0183. NMEA 2000 is still vaporware.

Assembly was straightforward, as was calibration. The Speed log feeds into the Wind instrument, and provides both Apparent Wind and True Wind. I mounted the three displays in a NavPod case. The case was then mounted on the coach roof on the starboard side just aft of the traveler arch (and inside the Dodger). The display is large enough that I can easily read it from the Helm. We chose to put it there so that is can be seen from all locations in the cockpit, including when it is raining and we may be hiding under the dodger. I don't like the idea of mounting instruments on the steering pedestal, since only the helmsman then can see it. I find that the more eyes watching the depth sounder when we are in shoal waters, the safer we are likely to be.

The instruments seem to be of reasonable quality. I occasionally get slight hum from them, and can't trace it down. The Standard Horizon service people are very nice and responsive (though you may have to wait on the phone for quite a while). They were puzzled by the humming noise, as they insist that there is nothing in the instruments that should cause a humming. Hmmm? The units are very compact and only require a 1.5 inch hole in the NavPod panel. We chose to go with a separate box, rather than cut all those holes in the cockpit bulkhead. In addition, if someone is resting against the bulkhead, and dozing off, you have to wake them to read the instruments. You do have to exercise caution when cutting a hole in the coach for all the wires.

The output of the instruments can be reviewed with your computer, using hypertrm.exe (on a PC Windows 2000 box). This will output a stream of NMEA data. However, in order to merge the outputs of the various instruments, you will need a Multiplexer, such as the Noland Engineering NMEA183-41 (another $180!). I understand that some of the newer units have multiplexers built into them (such as the Simrad IS-15?), and save the cost and aggravation of wiring it up.

The multiplexer is also essential if you want to merge the output of your GPS with that of the Wind, Depth and Speed. You will want to be able to do this if you wish to use these instruments to drive your autopilot. Our autopilot can accept the GPS Waypoints as well as Wind direction, and then can steer to Waypoint or to Wind or to Compass.

I feed the GPS output (directly, before the multiplexer) into our VHF (Also a Standard Horizon 1260) for GMDSS/MMSI. We are generally very pleased with the VHF. The Remote Control for the VHF is excellent. If we find that we have to send a distress signal, the VHF will automatically include our Lat/Long readings from the GPS.

The Wind transducer is mounted on the top of the mast, and since we have a wooden mast, running the wires did pose a bit of a problem. We finally managed it with advice from members of the bulletin board, and I can fill you in on details if needed.

Regarding the Standard Horizon GPS Plotters, they seem about equal to the Garmin, but I have the impression that the Garmin software is a bit more user friendly. My experience, however, is most recently related to my use of the Navman 40 handheld unit as a backup to our permanently installed unit. I was disappointed in several aspects of that instrument, particularly the software, and decided to go back to a Garmin. I returned
the NavMan 40 and I plan to order the Garmin 76 as a handheld unit. The Standard Horizon model 150 looks good, and it is fast. But the internal vector map is lousy. You really need to add the Chip, which greatly increases the cost. I have the impression that the Standard Horizon 150 gives you more value than a comparably priced Garmin, but after my experience with the NavMan 40, I would check out the software in detail.

There is a coming price-break on color Transreflective TFT screens on chartplotters. NavMan is now marketing a large unit under their own brand, as well as providing units to Standard Horizon. Worth checking them out at http://www.navman.com (I think that NavMan are also the people who manufacture the Wind, Depth and Speedo for Std. Horizon. They are down in New Zealand.)

regards, Harvey May 2002

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Your source of information about transducers is correct. Most of the companies use speed and depth transducers made by Airmar. The Airmar units are pretty sturdy, with a strong paddle wheel on the speedometer unit. Airmar provides the through hull with the flap valve to reduce water intrusion.

The Signet unit is much more flimsy, and is made and sold only by them. The repair cost on the Signet is almost twice the cost of a new Airmar. The repair kit for the Airmar is relatively cheap.

The "backing wood thing..." is formally known as a "backing wood plate" - but "backing wood thing" seems like a reasonable name.

regards, Harvey May 2002

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Phill,
You can also track down a fair amount of information about NMEA 0183 at http://vancouver-webpages.com/peter/ . That will take you to a number of other pages of interest.

regards, Harvey May 2002

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ummmmmmm
Raymarine may produce great equipment, etc. but I can personally attest that much of the older equipment acquired by Raytheon during their acquisitions (Autohelm, etc.) are not supported - no parts, no wiring diagrams, no advice (other than buy new), ... nothing! With regards to ANYTHING that Raymarine sells, I think I would wait a good looooooong while until I can validate that they will actually service the stuff .... LONG TERM. This is NOT cheap PC stuff that becomes obsolete when you open the box, why do they treat it so?

Anyone want several thousands of $$$ of useless instrumentation, tiller pilots, AutoHelm equipment - no longer serviceable, etc. because the manufacturer changed or upgraded to a newer model, and no longer supports the older stuff ???????????????

Rich Hampel May 2002

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I know that this is an issue with the Autohelm stuff. We have heard this from several people. Raymarine seems to be attempting to answer questions about the ST50 and other older stuff on their website, but their stance does appear to be buy new which would be more palatable if there was some sort of upgrade incentive. The ST50 instruments are not regarded very highly.

We have had good luck with Raymarine sales and service. We bought a remanufactured Tridata which was missing the knot transducer. We found this out while we were in the yard, hauled out, and ready to install. I called Raymarine and they had one overnighted from Airmark with no hassles.

We had a Navico Wheel Pilot that went belly up. We tried to get Simrad, the acquirer of Navico, to service the unit but their approach was to have as purchase new as they discontinued that model. It is unfortunate that acquiring companies sometimes choose this route.

Richard Brown May 2002

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Harvey,
This sounds a little too simple. Brooks & Gatehouse says that it's NMEA output will provide all of the data including the GPS data that was derived from the Magellan input. There are two terminals on the main controller that I am to attach the input leads from the radar. And of course it will work first time, right?

Alan Jett Louisville, June 2002

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Alan,
I'm not familiar with the Simrad radar. Call their office in either Florida or Lynnwood, Washington. They own Navico, and I have found them very helpful.

I know that our older Furuno (older = 2 years old) Model 1621 Radar, will display various Nav data. I haven't gotten around to wiring that into it. Not sure I will even bother, as I already can get all the info I need, with all the other instruments nearby. The newer units will even overlay the radar data on a Vector chart (on a chip) of the area, display weather report maps for the region, etc. (Also makes soup, and keeps an eye on your stock market investments). I also hesitated to add additional data to the radar display, as that reduces the area used to display the radar information.

regards, Harvey June 2002

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Alan,
In order for information from different instruments to flow smoothly, they have to stand in line, as kids in a school cafeteria. Otherwise it is chaos, with everyone speaking at once. This is the problem with simple NMEA. There are several well established ways to make everyone behave. One is to have a moderator, called multiplexer. The multiplexer asks each instrument to write down a note indicating the name of the speaker, and then the content that they want to communicate. The multiplexer puts each speakers note into a bin as it arrives. It then opens the note in sequence, Speaker 1, Speaker 2, etc. It then reads each of the notes, one at a time, to the devices that listen to the multiplexer. Your B&G instrument sounds as if it has a multiplexer built right into it. You are very fortunate, as it just saved you $180.

Your next job is to figure out which lead is the correct one to feed into the radar. It should be the Tx lead. There is also a Common.

Now read the manual on the radar. Find out which input on the radar should receive the Tx and which should receive the Common. The saving grace, if you make a mistake, is that if you cross the leads, it USUALLY (not guaranteed) doesn't cause any damage. But it's best if you carefully read all the pages, make believe that you did it and it didn't work, so you now will read the instructions once again.

Trust me, I'm not kidding. If anything can go wrong, it will.

Now read the manual a third time. Grit your teeth and start hooking up the wires. Now - wait. Check to make sure you hooked them up the way you intended to wire them. It "Should" work.

regards, Harvey June 2002

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Subject: Weather Fax

There are worldwide services (governments) that broadcast WeFAX. Yes, you can purchase a standalone WeFAX. What's also required is an SSB (or quality digital HF/shortwave receiver - Grundig Yachtboy, etc. and a dipole antenna, etc.) and either the standalone WeFAX or a PC & a demodulator to do the translation plus software. A printer is REAL nice so you can scribble your own personal forecasts derived from the downloaded data and overlayed onto the hard copy WeFAX.

I use a Macintosh (Macs don’t need demodulators, soundcards, etc.), a very inexpensive shareware program ("Multimode" - available from

http://www.blackcatsystems.com/software/multimode.html @ $39.00) and an old HF(shortwave) receiver. On the east coast of the US, I can get 1. WeFAX (From USA, Canada,& UK), 2. can decode telemetry (TTY)high seas forecasts, 3. receive NAVTEX (another telemetry forecast but broadcast to a small zone/area) via SITOR-B translation, ... PLUS 4. can direct download weather satellite images with a special (homebuilt helix) antenna (don’t have to wait for NOAA to view, translate and rebroadcast, etc. and then receive the same thing many hours AFTER the fact from NOAA WeFAX.) PCs onboard do suffer from corrosion, condensation, etc. ... probably better to buy used equipment and simply trash it when "cranky". Macs are renown for their reliability, etc.; I open mine up from time to time and spray in some "Boeshield" a moisture barrier, etc. developed by Boeing Aircraft for airplane instrumentation, etc.

IF I would have this equipment on-board (and not at home) on my recent sojourn into force 8 & 9 conditions for several hours, I would have been able to actually see what was going on ... in REAL TIME .... from the sat. photos, etc. (..... all the while NOAA was broadcasting 20 kts!!!!!!!) If I could have seen what was happening in REAL TIME, I could have retreated, or could have at least known which way to go. Obviously ALL the stuff goes on board from here on.

Just having WeFAX onboard doesn’t get you much as you have to interpret the data and do your own forecasting from the received data. There are several good texts available for onboard prediction as WeFAX data/charts need LOTS of personal onboard interpretation. I favor Steve & Linda Dashew's "Mariner's Weather Handbook", Beowulf,1998, ISBN09658028-2-5 .... especially for forecasting using the 500mb charts.

Some WeFAX website links:

http://www.hffax.de/ ***BEST*** website for WeFAX ... worldwide schedules, etc.--- over 16,000,000 website 'hits' per year!

http://www.blackcatsystems.com/software/multimodelinks.html
http://www.wunclub.com/
http://www.nws.noaa.gov/om/marine/radiofax.htm
Other ---- I'm in the process of integrating all onboard 'electonics' through my Mac. If I could find a small, fairly inexpensive, waterproof, sunlight-readable LCD to remote mount in the cockpit, I'd trash ALL my other 'instrumentation' readouts in favor of ONE small LCD. Would appreciate any advice on a source. Ditto for waterproof trackball or touchpad.

Rich Hampel October 2002

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Rich,

Many thanks for an excellent summary on WeFAX.

I have also been trying to find a reasonably priced monitor that provides good visibility in the cockpit. I have yet to test it on the boat, but I bought Elizabeth a Samsung 15" TFT monitor, with built-in video tuner/cable ready. It runs on 12 Volt DC output from the transformer/rectifier, so I thought it should also be useful on the boat in the event that my inverter gets fried. It has a reasonably sensitive TV tuner, and can also accept S-Video and Analog inputs from a DVD player and VHS tape player. I think it can even handle both PAL/SECAM and NTSC. The color and contrast is good, and it is easy to read the screen in even bright light, and even with dappled sunlight falling on the screen. But I have yet to haul it to the boat, as it was supposed to be a present for Elizabeth to use with her computer at home (with recollections of offers to buy her a new pair of skis - in my size - for her birthday, many years ago!). I think it has a contrast ratio of about 350:1. Don't know the NIT rating. It is not as crisp and bright in direct sun as the new Transflective TFT monitors, but is much cheaper, and available in larger sizes. The price at Fry's was about $550 or $600 about 8 months ago. Might be cheaper today. I saw an ad for the NEC TFT monitor with an even higher contrast rating for only $300, but without the video tuner.

Power consumption on these 15" units are generally about 50 watts or less. They are surely not waterproof! The 17" to 18" units require about 16-18 Volts DC, so you would be forced to rely solely on the inverter, but the larger screen is great for both computer and for watching DVD movies. They have about the same contrast ratios, and higher power consumption.

In comparison, Argonaut Computers is offering a fairly pricey 14" Transflective TFT for a couple of thousand bucks. Looks gorgeous. NIT rating is about 4 times that of the above mentioned units, and is definitely suitable for viewing in a brightly lighted cockpit. None of the current generation of mainstream laptop machines provide Transflective TFT, except for the small Panasonic Toughbook. But that is limited to about a 12" screen, and costs about $4,000. It has a fairly slow Intel processor due to the limited heat dissipation ability of a sealed and truly waterproof unit.

The last item on my list of things to test is a small portable DVD player designed for use in autos, as a means of keeping the kids quiet and avoiding the boredom of staring at glaciers and grizzlies as they drive through Alaska. These have lousy definition, poor viewing off angle, but are relatively cheap and come with a DVD player. Not sure if they can also double as a computer monitor.

Maybe some others have had a chance to evaluate other units.

regards, Harvey October 2002

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Rich,
I truly don't understand half your treatise on weather fax info but obviously you've done your homework. As for placing a readable laptop in the cockpit, I managed to sew a detachable self standing hood that fits over the laptop that in turn is mounted on the helm rail at seated eye height. It's made with the same Sunbrella material as the top. This idea served me very well this summer on these small creeks up and down the Chesapeake. My laptop is velcroed to a small aluminum plate screwed to a West Marine mounted aluminum swing arm. This unit remains mounted at the nav area until I reach unfamiliar waters when I bring it up and, using a rail mount contraption, suspend it there and plug it in. I also sewed a pocket into the cover and in it I place the small GPS, making the whole thing rather compact and manageable.

Bob O Kennon October 2002

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Subject: Weather Fax

I too only absorbed a part of what Rick said, but understand the broad strokes. What I still can't see is how these pictures beat the spoken word. For example, if the NOAA weather robot says there is a cold front stretching from Halifax to Toronto, what more good does a picture of it do me? Also since neither Phyllis or I know squat about weather prediction, we'd have to learn a heck of a lot from the book Rick suggests (and others?) before we could even use the thing.

There are places that specialize in weather proofed (and other proofed) computers. This outfit is one. This link will take you directly to a page discussing this company's daylight viewable LCD panel.

http://www.amrel.com/asi_productother.html
I had a flurry of activity in my business selling to auto repair places which needed armored keyboards to prevent metallic debris from falling in. This outfit seems more gov't vendor, but there are others too. There are waterproof computers too.

I have an HF from Radio Shack which is about the same as a Grundig YB. What is it that Mac's have that my laptop PC doesn't which acts as a demodulator? That is, how do I get the signals from the HF to the PC? What freq's are these signals?

If I understand this thing now, I can, if I want, somehow rig my HF to a demodulator to the PC and run short wave on the PC that will display a weather map. All I need is the demodulator, the short wave radio and the freq's for the broadcasts.

Have I got this right?

Paul Cassel October 2002

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If you have an HF with an external speaker output, and a laptop with a built-in "sound card" like most have you can...

1) Wire the speaker output to the line audio input of the laptop. If you don't have a line audio input, you can connect to the microphone level input, but it helps to have a pair of resistors in the circuit to cut the audio level down a fair bit or you end up turning the radio down very low so you don't swamp the computer (at least that's what happened with my Micron laptop and my Icom 710RT HF radio.)

2) Download a program called JvComm32 from http://www.jvcomm.de/. It's shareware. Try it out and then send them the 60 Euros after you see how good it is.

3) Or, you can buy a "dedicated" Furuno WeFAX for about $1500 which doesn't need a laptop nor an HF.

Why weatherfax?

a) I'm just a "visual" kind of guy, not an "auditory" kind of guy. I can listen to Caribbean Weather Service all day long and about 10% of it sticks. With me, a picture is worth a thousand words.

b) I just set it and forget it. With audio weather I have to be paying attention at the exact moment they are talking about what I want to hear. Somehow my attention span isn't that long and I am always daydreaming during the important parts.

I just downloaded the latest update (haven't installed it yet) and I see they have NAVTEX decode, too... way cool. A good web site on the subject:

http://www.geocities.com/bill_dietrich/Radio.html#Weatherfax
Charlie s/v Kamaloha T37 #542 October 2002

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Subject: FM/TV antennas

take a look at:

http://groups.google.com/groups?q=%226-66+antenna%22&hl=en&lr=&ie=UTF-8&selm=6fcf8c%24sbj%40bgtnsc02.worldnet.att.net&rnum=1 for a fairly effective omni directional VHF/UHF 'homemade' antenna. The above discussion is for use with a coax lead-in line. I use twin lead (stores easier) and simple transformer at the set. I also used 1/4" instead of 3/8".

I surmise that you're going far South and East. TV systems throughout the world use different standards. The USA and many of the Caribbean islands use system M; but, Guadeloupe, Martinique, Fr. Guiana and other French possessions, etc. use system K. Argentina, Bolivia, Uruguay, Paraguay use system N. Of course, all these different systems are incompatible vs. receivers from 'outside'. For HDTV, it looks like it will all be one standard.

Rich Hampel November 2002

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A splitter separates frequency. It divides the VHF frequencies and the FM frequencies so you can do VHF and FM off of one antenna. It is different from a booster and certainly does not increase gain. It splits at the weather channels so that they go with the VHF radio. I called Shakespeare to find out what was going on when I installed mine to figure out what was going on with the frequencies. I could live without weather on the AM/FM/CD player so I left it in place. The reception is good on both VHF and FM, I have a new antenna and large coax cable which probably helps more than anything.

Joe Sprouse Sojourn October 2004

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A friend of mine is down in Mexico and calls us from Internet cafes using Skype (www.skype.com). The connection is not quite as good as a land line, but all you are paying for is the Internet café time. When not on land, they use Sailmail with their marine SSB.

When I am up in Canada, I use a cell phone through Verizon. Their base plan works anywhere in Canada, the US, or Mexico with no roaming (assuming that you can get service). However, I never could get the data service to work in Canada. I have a cell phone on the mast and can usually hit a cell way before I can pick it up on the boat. Another cool, but pricey, alternative is this amplifier

(http://www.digitlantenna.com/cellamprep_DA4000MR.html.
It doesn't require any cables.

Regards, Andy Brown www.KalliopeSV.com March 2005

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I wonder what has been the experience of our group in regards to the accuracy of speedometer readings. We have a fairly new Airmar through hull transducer. It is mounted just forward of the mast, about 6" to the port side of the midline. I think that it is less than perfectly aligned to the lubber line of the boat, and may be rotated a few degrees clockwise (seen from above), but it is not substantially off axis. The output is sent to a Standard Horizon gauge in the cockpit. It is about 2 years old. I find major discrepancies when on a port vs. a starboard tack. This does not appear to be a result of major differences in boat speed. When on a starboard tack, the readings "more or less" agree with my GPS (accounting for current along the coast). When on a port tack, the speedo now will often report 1.5-2 knots higher. Part of this may have to do with relative balance, the fact that I am left handed, and favor a port tack, but I doubt it. The readings, in 9-12 knots of wind will sometimes rise to 8.4 knots when we are close hauled. The GPS will be reading about 5.8 SOG. I know that under these conditions a Tayana 37 just can't be doing 8.4 knots! (Gee whiz. That Harvey is one hell of sailor!) I have calibrated the speedo on a few occasions, and it is close to the mark.

If I then drop sails, and now am motoring level (in the same current), the knotmeter now generally agrees with the GPS SOG. Question:

1) Could it be a defective transducer? Asymmetrical friction or unstable axis pin?

2) Peculiarity of laminar flow of water such that when heeled to starboard, there is some sort acceleration of flow on the port (more superficial) side with the transducer riding between the surface and the aileron like surface of the keel? The Airmar transducer is the same unit used by virtually all manufacturers (except for Signet).

regards, Harvey May 2005

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The keel is a foil (lifting body) just like a wing or a sail ........ hydrodynamics / aerodynamics of incompressible fluid flow.

With the transducer/paddle wheel being off-center you will always have 'irregularities' in speed measured due to the 'slip' of the keel (keel is going sideways at a small angle - as well as forward). Even if you mounted directly ON the centerline, you'd still have to correct for sideways slip, turbulence, etc. What you are *seeing* is the 'recirculation' flow differences about the foil when its 'lifting' (towards windward side) .... and if the paddlewheel's position is off center it will make the 'anomaly' worse. Just like ANY gauge reading involving 'motion', there are 'sensible' components and 'latent' components .... and the layman just simply ignores all the latent (correction needed) readings. That's right! ***ANY*** gauge that is measuring a 'movement' has to be mathematically and continuously corrected for accuracy. Keep it simple and simply recognize that a speedo paddle wheel when sailing will ALWAYS give the WRONG reading ... and simply ignore those 'resolution' errors. Now you know why the paddle wheel shouldn’t be mounted 'anywhere near' a keel. ;-)

The only way to correct this is to construct a 'deviation card' and add the correction numbers to the 'as-read' numbers. When motoring or direct downwind sailing ... and the keel isn’t 'flying'/slipping can the numbers can be considered accurate (once calibrated). Anytime the keel is 'lifting' all the speedo numbers go out the window when it comes to accuracy ... deep high aspect ratio fin keels (and sails and wings) are worse in this respect.

Rich Hampel May 2005

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.... move the location of the paddlewheel back to about mid-cord of the keel and about 2 feet from the centerline / keel-root surface ... not 'perfect' but much better than near the 'nose' of the keel. At least in that position the paddlewheel will be more outside of the zone of variable flow over the keel leading edge. This position won’t be perfect but will give better readings.

Especially with that poorly designed (abysmal) keel leading edge shape (not Perry’s design, but a Tayana yard error) you will get very unstable flow anywhere near that keel leading edge. Perry designed a NACA-10 shape for the keel leading edge .... the Tayana yard 'blew-it' and Perry didn’t discover the error until long AFTER the molds were constructed. BTW - if you reshape the leading edge to a NACA-10 you will point much better and the boat will be much faster overall - I'm reshaping mine in 'parts' as I go. (I have NO idea what to do about that horrendous 'flat bulb shape' at the bottom 'knuckle' of the keel.)

Rich Hampel May 2005

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Hi Harvey,

Rich is right on about knotmeter placement. Years ago I noticed this and put a knotmeter on either side of my keel with a gravity changeover switch. I don't have that setup anymore but I recall the same discrepancies as you noted. Of course, I could activate the switch manually and get a direct comparison. But these were back in the days when I didn't write things down since I knew that I would remember the data forever. Ha! I do remember that the error did directly relate to angle of heel. The more heel, the more error. Note that the knotmeter is probably fairly accurate on both tacks downwind (not much lift on the keel.

Wayne V-42 C/C RESTLESS May 2005

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Does anyone have any experience with the new wireless instruments available such as those sold by a company called Tacktick?

http://www.tacktick.com/products/mn100_index.asp
I see that West Marine is now carrying their product as well.

John Hovan s/v Celtic Dream May 2005

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The current issue of Practical Sailor has an interesting letter. Apparently the instruments are sealed and not factory repairable. Therefore, when the battery dies, which could be as little as 5 years, the unit is discarded and $1,000 down the drain. The company offered one unhappy customer a 20% discount on a new unit.

Harry & Melinda Schell Sea Schell May 2005

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Subject: Wireless Instruments?

On Tayary, I still have wooden masts and purchased the wind gauge to avoid the wiring. It works very nicely for me with an NMEA interface to the other instruments. Not aware of the battery replacement issue but should be easy to check, they have a very good tech support.

Dave Allin TAYARY T37 Ketch May 2005

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Dave,

I'm interested in hearing more details of the system. Does the wind system just consist of the masthead unit and control head? Did you have to buy the $399 NMEA interface with it? Did you purchase yours from West Marine?

In the west marine catalog, it looks like the wind unit and NMEA interface would run about $1500.

thanks, John Hovan s/v Celtic Dream May 2005

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John,
The wind system is just the masthead and the remote analogue display and, yes, you need the extra unit for the NMEA interface. Boats are never cheap!. The wind unit and its analogue display are solar powered with a battery storing the solar charge to allow night running. So far no problems of a flat battery. You can walk around with the gauge so have it by the chart table, in the cockpit as desired. It comes with a small mounting bracket with which you mount and just clip on. The NMEA box sits downstairs and wires into the normal battery. I am in the Netherlands and bought both units at the boat show in London with a discount after some bartering. Sorry, I cannot say what US prices will be.

Dave May 2005

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David,

Someone on the Island Packet list says the batteries were so poor in the units, that the units would not function into the morning hours. He also said they had issues calibrating the mast head wind unit.

Have you had any of these issues with your units? Have you tried them on an all night sail?

John Hovan May 2005

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