Meindert,
The problem is that all the Raymarine Seatalk cables use red for yellow
for data, red for + volts, and the shield for - volts. Saves cost of s
third wire.
krj

Meindert Sprang wrote:

"krj" wrote in message
. ..

Larry,
Do you have ferite beads at both ends of all your NMEA cables? If so, do
they help?


Ferrite beads don't do much on HF, but all the more on VHF. But like I said
in me other replay, it's more important to terminate the wire correctly. If
you have a shield, do not use it as a signal return as with coaxial cable.
Only connect it on one side so no current can flow through the shield,
otherwise it will radiate being a perfect antenna.

Meindert

"krj" wrote in message
.. .
Meindert,
The problem is that all the Raymarine Seatalk cables use red for yellow
for data, red for + volts, and the shield for - volts. Saves cost of s
third wire.
krj

I see. What you *can* do against HF interference is to run each cable 10
loops through a ferrite ring core.

Meindert

"Doug Dotson" dougdotson@NOSPAMcablespeedNOSPAMcom wrote in message
...

"Glenn Ashmore" wrote in message
news:QnpXd.56586$SF.18771@lakeread08...



"John Proctor" wrote in message
news:2005030907232116807%lost@nowhereorg...
Here is a scarry thought.

My wife went in for LASIK surgery to her eyes. Basically it a laser
procedure where they correct your eyes for astigmatism. They use a
laser interferometer to map the surface of your eyball and them use
mathematics to work out the sequence of laser blasts to ablate the
eyball surface to generate good vision. The gave her a DVD of the
process they did on her eyes and guess what? The whole thing is
controlled by a Windoze PC. I wonder what would happen if the blue
screen of death came up in the middle of a procedure;-)

I noticed to that when I got my eyeballs spot welded. But I had a
couple
of
Valums working so just bowed towards Redmond, WA and crossed my fingers.
:-)

I've been running my laptop almost 24/7 for about a year and a half and it
has
yet to crash. I hope the eye doctor was running XP.

Doug

--
Glenn Ashmore

I worked for about a year (4 years ago) as a test technician at an OEM
company that made embedded microprocessor products for several medical
electronics firms for eye surgery. Quite often the boards we tested were
small quantities and we usually had no clue what some of the connectors
interfaced with once we sent them to our customer. However, silk screen
labels such as foot pedal left, right, forward, back, up, down, etc raised
my curiosity. It seems the eye surgeons use a foot pedal control similar to
the clamp on skates we played with as children. Yes, the processors and
firmware used Intel products, so I am not surprised there is a Windows XXX
interface, but I doubt if Windows was directly controlling the surgery. I
suspect it was used for logging and visual magnification, etc. The OEM
boards appeared to be the surgeon interface to the laser and fluid washers,
etc.

73 Doug K7ABX

"Meindert Sprang" wrote in
:

So if everyone adhered to the standard, connecting NMEA would
have been as easy as connecting a ligthbulb.....

Meindert


An all multiplexers should use STANDARDIZED SHIELDED CONNECTORS, not some
open screw terminals just waiting for something to touch
them.......grrrr.....(c;

krj wrote in
:

Larry,
Do you have ferite beads at both ends of all your NMEA cables? If so, do
they help?
krj



I tried that, too. They reduce the noise, somewhat, but the open screw
terminals on the Noland multiplexer, the unbalanced lines making all the
unshielded NMEA cables into a giant transmitting antenna just bypass them
beads or clamshell ferrites so much it's nearly useless.....

I bought a new Maxtor 300 GB external portable hard drive for my system,
today, in a moment of weakness at Best Buy ($299). It came with the nicest
WELL SHIELDED USB-2 and Firewire cables with clear plastic coverings so you
can see the braided shield inside....oh, the longing for a whole boat
network like that...(c;

"Larry W4CSC" wrote in message
...
"Meindert Sprang" wrote in
:

So if everyone adhered to the standard, connecting NMEA would
have been as easy as connecting a ligthbulb.....

Meindert


An all multiplexers should use STANDARDIZED SHIELDED CONNECTORS, not some
open screw terminals just waiting for something to touch
them.......grrrr.....(c;

Yeah Yeah.....

When you are installing this stuff for living, you very soon learn to
appreciate the absence of fixed connectors on cables..... or do you want to
make all holes in bulkeads bug enough for all connectors to push
through..... just once.....

Meindert

On Mon, 14 Mar 2005 07:02:18 +0100, "Meindert Sprang" wrote:

"Larry W4CSC" wrote in message
...
"Meindert Sprang" wrote in
:

So if everyone adhered to the standard, connecting NMEA would
have been as easy as connecting a ligthbulb.....

Meindert


An all multiplexers should use STANDARDIZED SHIELDED CONNECTORS, not some
open screw terminals just waiting for something to touch
them.......grrrr.....(c;

Yeah Yeah.....

When you are installing this stuff for living, you very soon learn to
appreciate the absence of fixed connectors on cables..... or do you want to
make all holes in bulkeads bug enough for all connectors to push
through..... just once.....

Meindert


Am I over looking something? Can't the cable be routed,
then the connectors installed? Might make a neater
installation, avoiding coils of excess cable....or cables
which might be too short.
Norm B

"engsol" wrote in message
...
On Mon, 14 Mar 2005 07:02:18 +0100, "Meindert Sprang"
wrote:

When you are installing this stuff for living, you very soon learn to
appreciate the absence of fixed connectors on cables..... or do you want
to
make all holes in bulkeads bug enough for all connectors to push
through..... just once.....

Meindert


Am I over looking something? Can't the cable be routed,
then the connectors installed? Might make a neater
installation, avoiding coils of excess cable....or cables
which might be too short.

No, you're not overlooking. But it just feels plain stupid to first cut the
plugs, route the cables and then reassemble them. What would you like to do
most: solder a plug with tiny contacts or just strip the wire, crimp on a
pin and screw them into a screw terminal?

And believe me, it's not just theory but this is backed up with
measurements: a 4800 baud signal is just not going to produce interference
because the last inch is not screened and connected to screw terminals. They
are physically too small to be able to radiate enough energy to interfere
with an SSB.

Meindert

Have you priced a crimping machine that is capable of dealing with most
reasonable moisture proof connectors?

Doug

"engsol" wrote in message
...
On Mon, 14 Mar 2005 07:02:18 +0100, "Meindert Sprang"
wrote:

"Larry W4CSC" wrote in message
...
"Meindert Sprang" wrote in
:

So if everyone adhered to the standard, connecting NMEA would
have been as easy as connecting a ligthbulb.....

Meindert


An all multiplexers should use STANDARDIZED SHIELDED CONNECTORS, not
some
open screw terminals just waiting for something to touch
them.......grrrr.....(c;

Yeah Yeah.....

When you are installing this stuff for living, you very soon learn to
appreciate the absence of fixed connectors on cables..... or do you want
to
make all holes in bulkeads bug enough for all connectors to push
through..... just once.....

Meindert


Am I over looking something? Can't the cable be routed,
then the connectors installed? Might make a neater
installation, avoiding coils of excess cable....or cables
which might be too short.
Norm B

On Mon, 14 Mar 2005 19:25:40 +0100, "Meindert Sprang" wrote:

"engsol" wrote in message
.. .
On Mon, 14 Mar 2005 07:02:18 +0100, "Meindert Sprang"
wrote:

When you are installing this stuff for living, you very soon learn to
appreciate the absence of fixed connectors on cables..... or do you want
to
make all holes in bulkeads bug enough for all connectors to push
through..... just once.....

Meindert


Am I over looking something? Can't the cable be routed,
then the connectors installed? Might make a neater
installation, avoiding coils of excess cable....or cables
which might be too short.

No, you're not overlooking. But it just feels plain stupid to first cut the
plugs, route the cables and then reassemble them. What would you like to do
most: solder a plug with tiny contacts or just strip the wire, crimp on a
pin and screw them into a screw terminal?

And believe me, it's not just theory but this is backed up with
measurements: a 4800 baud signal is just not going to produce interference
because the last inch is not screened and connected to screw terminals. They
are physically too small to be able to radiate enough energy to interfere
with an SSB.

Meindert


Yep, soldering tiny pins is no fun. I agree 100% that 'strip n crimp'
is the way to go. When I was doing embedded controllers for
ag equipment, I used 3M plastic circular mating connectors. They had the
advantage of strain relief and some protection from dust and moisture,
to say nothing of accidential shorting.

As to 4800 baud radiating for 1 inch unshielded...not much chance of that.
The only exception might be if the rise time of the pulses was quick
enough...often seen in switching power supplies....to cause the old
'comb' of harmonics.
Norm B