Ok, class, let's turn our March 2006 Cruising World to page 44, a new
article on NMEA 2000, the do-all CANbus solution to NMEA0183's
deficiencies.

For class, tomorrow, look through the whole article and count the number of
times you see the P-word, PROPRIETARY, in the article.

But wait! I thought NMEA 2000 was gonna make it so everyone's stuff would
talk to everyone else's stuff, solving the old P-word problem that's
plagued boat electronic crap since the invention of the DIN connector?
Whatzwidat?

Interesting information on:
http://www.interfacebus.com/NMEA-2000_Standard.html

"CAN Bus uses a Drive Voltage: High; 2.75v to 4.5volts, Low; 0.5 to
2.25volts, Differential 1.5v to 3.0volts"

and...once again....we're stuck with an interface bus whos lack of good +
and - voltage levels dooms us to slowdowns from cable length, system
noises, intersecting fields....just like an old unbalanced mic.

Let the interfacing begin!....

Raymarine webpage:
"Interface cable for connecting E-Series displays to Raymarine SeaTalk 2 or
3rd party NMEA 2000 Devices.
Product Number: E55053
Suggested Retail Price: $50.00"
(keyword CABLE....it's just a cable with 2 connectors for $50)

Panbo's connector expose:
http://www.panbo.com/yae/archives/001137.html
Lowrance...not compatible connectors....(sigh)
http://www.panbo.com/yae/archives/001247.html

Someone emailed me to ask what I thought this would do for his HF noise
problem, where his NMEA0183 system trashes his M802/AT130 across the HF
spectrum, rendering it useless unless you shut down the whole NMEA network
if you want to use HF or NAVTEX or WEFAX or Sailmail or ham radio.

CANbus is used in every new car, which is where NMEA ripped the idea in the
first place. I'd like to invite you all to beg, borrow or steal a portable
shortwave receiver (HF) and go for a ride in a 2000+ car/truck or SUV up
the interstate. Listen up and down the HF spectrum to see what CANbus
sounds like coming from the car's network system. HF ham radio is damned
near useless in a new car or truck. It's just awful..... Will boats be
different? Looking at Lowrances cheap plastic connectors, you just know
the system will be all balanced and all just sealed up tight with
shielding, included shielded instruments, right? Yeah, right.....

Time will tell......another serial bus bites the dust....

Maybe they'll pick USB next time!....to proprietize....

and...once again....we're stuck with an interface bus whos lack of good +
and - voltage levels dooms us to slowdowns from cable length, system
noises, intersecting fields....just like an old unbalanced mic.

No, it's a matter of don't use the wrong bus for the wrong application.

Maybe they'll pick USB next time!....to proprietize....

Which is also limited on voltage levels.

Panbo's connector expose:

Which went on to cover how the various players stepped BACK from proprietary
connectors.

If you're going to post, at least try not to be WRONG on nearly ALL your
points.

"Larry" wrote in message
...
Interesting information on:
http://www.interfacebus.com/NMEA-2000_Standard.html

"CAN Bus uses a Drive Voltage: High; 2.75v to 4.5volts, Low; 0.5 to
2.25volts, Differential 1.5v to 3.0volts"

and...once again....we're stuck with an interface bus whos lack of good +
and - voltage levels dooms us to slowdowns from cable length, system
noises, intersecting fields....just like an old unbalanced mic.

Larry, you're talking nonsense now. It is a *balanced* bus and therefore
insensitive to noise,.just like your favourite ethernet, and the voltage
levels are even *higher* that your favourite ethernet. So don't whine if you
don't know what you're talking about.....

Someone emailed me to ask what I thought this would do for his HF noise
problem, where his NMEA0183 system trashes his M802/AT130 across the HF
spectrum, rendering it useless unless you shut down the whole NMEA network
if you want to use HF or NAVTEX or WEFAX or Sailmail or ham radio.

If his NMEA-0183 network trashes his HF comms, there is something wrong with
the installation. Example: we tested our multiplexers for RFI and the
emissions where below the limits of the IEC/EN60945, which means you cannot
hear any interference on marine HF and VHF bands. This simply means that
NMEA-0183 can be perfectly HF friendly. One mistake made by many people is
that they connect a balanced/differential output to a single ended input,
effectively connecting the B signal of the output to ground. That *will*
produce HF interference but this is simpy caused by wrong wiring.

CANbus is used in every new car, which is where NMEA ripped the idea in
the
first place. I'd like to invite you all to beg, borrow or steal a
portable
shortwave receiver (HF) and go for a ride in a 2000+ car/truck or SUV up
the interstate. Listen up and down the HF spectrum to see what CANbus
sounds like coming from the car's network system. HF ham radio is damned
near useless in a new car or truck.

CAN in cars is often single ended and therefore radiating as hell. CAN in
NMEA 2000 is balanced and should be silent. Especially when NMEA-2000
equipment is EN60945 certified (mandatory when used on vessels sailing under
SOLAS rules), you can be absolutely sure that it does not interfere on
HF/VHF.

It's just awful..... Will boats be
different? Looking at Lowrances cheap plastic connectors, you just know
the system will be all balanced and all just sealed up tight with
shielding, included shielded instruments, right? Yeah, right.....

Even plastic connectors can have shielding Larry. Besides, does you
favourite ethernet network produce any interference on HF (being UTP and
all, plastic RJ-45 etc. etc.)?

Meindert

"Meindert Sprang" wrote in
:

Even plastic connectors can have shielding Larry. Besides, does you
favourite ethernet network produce any interference on HF (being UTP and
all, plastic RJ-45 etc. etc.)?

Meindert



AS with BALANCED NMEA-0183, you don't REALLY think they are ALL going to go
the distance and NOT ground data - to ground, do you?....(c;

There's no real Ethernet in the Ethernet router on the boat. The ports
aren't hooked to anything usable as an antenna. The Ethernet is all
wireless on 2.4Ghz so it makes no noise.....

Are they all going to shield the plastic instrument cases without being
forced to, too? Lots of them radiate through the cases.

"Larry" wrote in message
...

Are they all going to shield the plastic instrument cases without being
forced to, too? Lots of them radiate through the cases.

Why would they? Like I told you about my multiplexers: they are in plastic
cases and they don't radiate sufficiently to interfere.
To radiate, you need an antenna. To radiate on HF, you need a large antenna.
A circuitboard of a small device is not large enough, it needs the connected
wires to radiate.

Meindert