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,
________________________________________________________________________
Wow,
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,
Wayne Strausbaugh
V-42 C/C RESTLESS May 2002
________________________________________________________________________
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,
________________________________________________________________________
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
________________________________________________________________________
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
________________________________________________________________________
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,
________________________________________________________________________
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
________________________________________________________________________
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
________________________________________________________________________
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
regards,
________________________________________________________________________
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,
________________________________________________________________________
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,
________________________________________________________________________
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
________________________________________________________________________
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
________________________________________________________________________
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
________________________________________________________________________
Alan,
I'm not familiar with the Simrad
radar. Call their office in either
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,
________________________________________________________________________
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,
________________________________________________________________________
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
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
________________________________________________________________________
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
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
Maybe some others have had a chance
to evaluate other units.
regards,
________________________________________________________________________
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
Bob O
Kennon October
2002
________________________________________________________________________
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
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
________________________________________________________________________
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
________________________________________________________________________
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
________________________________________________________________________
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
________________________________________________________________________
A friend of mine is down in
When I am up in
(http://www.digitlantenna.com/cellamprep_DA4000MR.html.
It doesn't require any cables.
Regards, Andy Brown www.KalliopeSV.com March 2005
________________________________________________________________________
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
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,
________________________________________________________________________
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
________________________________________________________________________
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
Dave May 2005
________________________________________________________________________
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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