Thank you, Kelton.
That's just the detailed information I was looking for! I guess this will
have to be one of my next projects - I'm getting tired of seeing all those
wires under the instrument panel. This should let me get the wires organized
so that I can have a neat installation and eliminate or stow the excess
wires.

Bill
"Kelton Joyner" wrote in message
...
William,
I have a mount for my GPS in the steering pedestal. I mounted a four
terminal block inside the pedestal and wired +battery and -battery to
the block.
1. The four wire Garmin cable is connected to the block ( +, -, data in,
data out ).
2. A two wire cable is connected to the block ( -, data out )and routed
into the instrument pod and connected to the autopilot NMEA - and +
terminals.
3. From the terminal block I ran a four conductor cable down to my
navstation area. I installed another four terminal block there and
connected the cable to the block.
4. The VHF radio acessory cable GPS data in and - are connected to the
block ( Garmin data out and - ).
5. The Pactor IIe cable to the HF radio is a "Y" cable (available from
Faralon Electronics). The "Y" had a DB9 connector. I made a DB9 pigtail
cable and connected the data in and - to the block ( Garmin data out and
- ).
6. I made a another DB9 pigtail to connect to the computer. Data in an -
to Garmin data out and -.
7. I also connected second Garmin data cable to the block so that I
could remove the GPS from the pedestal and use it at the navstation
(usefull when planning routes and uploading them to the GPS).

Kelton
s/v Isle Escape



William G. Andersen wrote:

Kelton,
You seem to have done what I want to do. How did you physically connect
one
Garmin to four devices? What parts/connections did you buy?

"Kelton Joyner" wrote in message
...

The manual with my Garmin GPS48 states that it will drive 4 listeners. I
have it connected to the autopilot NMEA input, VHF DSC input, computer
input, and Pactor IIe input. Works OK.All devices get and process the
GPS NMEA sentences.
Kelton
s/v Isle Escape

Rodney Myrvaagnes wrote:

On Mon, 16 Aug 2004 19:50:12 +0200, "Steve Lusardi"
wrote:



Lisa,
NMEA interfaces are slow and bit serial (EIA RS-232). The protocol is

very

basic and there is no provision for either addressing or data

collisions. As

you stated, your solution is incorrect, the device to use is called a
statmux or statistical multiplexor in general. Specifically, there are
multiplexors available for this purpose that prevent data collisions
and
allow orderly sentence broadcast. Contact a qualified nav equipment

dealer

for further info. These devices are inexpensive and available.
Steve


Since Lisa was only proposing a single "talker" a mux is superfluous.
No collisions could occur. The only issue is whether the two loads
would reduce the signal too much.

But, since you mention it, where are there inexpensive muxes? I had
one once until it was hit by lightning, but it was very expensive at
the time.

Thanks




Rodney Myrvaagnes NYC

J36 Gjo/a


"Wanting to meet a writer because you like his work is like wanting to

meet a duck because you like pate."

Margaret Atwood

"Martin" wrote in message
...

Well, depends on what you call inexpensive. The world-famous Noland
multiplexer is about $200. Ours are a bit more expensive (starting from
around $250) but have more functions and comply with the EMC rules ;-)

Meindert


Keep away from the Brookhouse mux's from New Zealand. I had one which
never
worked properly and their tech support is lousy.


Very nice, Martin Perry!
This guy wanted to become an agent for Brookhouse in the UK on his
conditions, which we rejected. This is how he tries to get back to us.
He had problems getting the Seatalk option to work in a very messy
installation. We bent over backwards to help, but he decided he did not need
the Seatalk option after all and was refunded.
Brookhouse

Meindert Sprang wrote:

"Brent Geery" wrote in message
...

On Tue, 17 Aug 2004 09:06:49 -0400, Jack Erbes
wrote:


Some people will argue about doing it but my preference is to strip and
tin all wires before crimping the terminals on as it gives one solid
bundle for the crimp to act on.

That's not a smart thing to do. If the connection ever overheats for
some reason,


It doesn't even have to get overheated. Solder flows, also in cold
condition. You can test that yourself: tin the end of a stranded wire, put
it into a screwterminal and tighten it. After a week or so, check if the
screw is still tight: it isn't.

Crimp first. Then apply some solder if you like.


Like I said, some people will argue about it... :)

If the wires are hot enough to melt solder the insulation is also
probably starting to melt away and you have more problems than a simple
loose connection. Also, in a marine environment, a tinned end will
arguably oxidize less and corrode less over time than an untinned end.

Look at the untinned copper wire connections on terminal strips in a 50
year old boat if you don't believe me. Soldering can be a bad choice
(like if acid core solder is used) but it has some good points too.

And I described crimping a spade lug onto the tinned end and putting
that under the terminal screw, not putting the tinned strands under the
screw.

Some crimpers leave a flattened clamping area that will let untinned
wires shift around in it and then the crimped spade terminal can lose
its grip. I was talking about the average hardware store terminal, put
on with the average hardware store crimping tool, by a non-professional
doing his own work. I know a little about four point crimpers, full
contact compression or swaged crimps, and other ways to get both good
contact and high pull strengths but the terminals and tools are not
found in the average hardware store.

As far as trying to solder on terminal lugs that have already been
crimped on? That sounds nothing short of bizarre to me. To each their
own I guess.

Jack

--
Jack Erbes in Ellsworth, Maine, USA - jacker at midmaine dot com

"Jack Erbes" wrote in message
...
Meindert Sprang wrote:

It doesn't even have to get overheated. Solder flows, also in cold
condition. You can test that yourself: tin the end of a stranded wire,
put
it into a screwterminal and tighten it. After a week or so, check if the
screw is still tight: it isn't.

Crimp first. Then apply some solder if you like.


Like I said, some people will argue about it... :)

This is not a myth or a point of argument. It is the truth. I learnt it at
school that solder 'flows' when stressed in cold condition. And my personal
experience proves me right too.

If the wires are hot enough to melt solder the insulation is also
probably starting to melt away and you have more problems than a simple
loose connection.

Did you read what I wrote: the wires DO NOT HAVE TO BECOME HOT. SOLDER FLOWS
AT ROOM TEMPERATURE WHEN UNDER MECHANICAL STRESS!


Also, in a marine environment, a tinned end will
arguably oxidize less and corrode less over time than an untinned end.

I won't argue about that, that is correct. But there is a difference between
tinned stranded wire and stranded wire that is tinned after stripping. The
first doesn't have the wires soldered together and allows the single strands
to set firm in a crimped or screwed terminal. In the last case, you actually
crimp or clamp a 'lump' of solder with some strands in it, without a decent
mechanical cohesion.

And I described crimping a spade lug onto the tinned end and putting
that under the terminal screw, not putting the tinned strands under the
screw.

Same bad procedure.

Some crimpers leave a flattened clamping area that will let untinned
wires shift around in it and then the crimped spade terminal can lose
its grip. I was talking about the average hardware store terminal, put
on with the average hardware store crimping tool, by a non-professional
doing his own work.

These cheap crimpers will do a worse job on tinned ends too. I agree that
untinned strands can shift around, but tinning them first will give you a
solid connection only for the first hours or days. A crimped terminal
applies a constant stress on the copper, which ensures that it holds. If you
tin the ends first, you apply a constant stress on the solder or on strands
clogged together with solder. Eventually the solder flows, trying to release
from the stress and you end up with a connection that is even moore loose
than without tinned ends.

As far as trying to solder on terminal lugs that have already been
crimped on? That sounds nothing short of bizarre to me. To each their
own I guess.

That is a good practise. The stress is on the copper strands only and the
remaining gaps are filled with solder, without stress.

Meindert

Meindert Sprang wrote:

This is not a myth or a point of argument. It is the truth. I learnt it at
school that solder 'flows' when stressed in cold condition. And my personal
experience proves me right too.

Almost everything "flows" under pressure. I like to think of the
process as the material being swaged or formed.

Doesn't the flow stop at some point in the process as the pressure
relaxes? After the crimp is made, a pressure equilibrium should develop
that is the point where the two pressures (the clamping force from the
terminal and the "flow" in the solder) stabilize.

At that point there is a fairly constant and stable mechanical
connection between the two, electricity can flow across it, and it takes
some pretty sophisticated equipment to measure the resistance in the
connection. Simply stated, for the conditions it is good enough for the
job and it works.

Other factors (unsupported weight, vibration, etc.) enter into the
equation as far as the danger of "flow" contributing to conductors being
pulled away from a terminal. If you start shaking the wire, pulling on
it, or applying external heat, things can or will change.

Did you read what I wrote: the wires DO NOT HAVE TO BECOME HOT. SOLDER FLOWS
AT ROOM TEMPERATURE WHEN UNDER MECHANICAL STRESS!

Yes, I did read it, you don't have to yell. My comment about
overheating was in response to your comment:

That's not a smart thing to do. If the connection ever overheats for
some reason...

Anyway, I generally always tin stranded copper wire before I crimp a
terminal on. Have been doing it for years, and have not had any
systematic or recurring problems because of it.

If you can give me a reference that states that tinning stranded bare
copper wires before crimping a terminal on is a bad thing to do I'll
reconsider my ways. Otherwise we are entitled to have differing opinions.

And I pay attention to a number of other things too. Like the length of
the stripped and tinned wire, the type of crimper I am using, exactly
where on the length of the crimping area on terminal the crimp is made,
and the orientation of the seam in the terminal as I crimp it on.

And I give every terminal a good hard pull test after the crimp is made.

Maybe me ought to move on to a less controversial topic, like Talmudic
Law, or Which Religion is Best...

Cheers,

Jack

--
Jack Erbes in Ellsworth, Maine, USA - jacker at midmaine dot com

In article ,
(Jack Erbes) wrote:

tinning stranded bare
copper wires before crimping a terminal on is a bad thing to do

I have been told that it acts as a stress raiser at the point where the
tinning ends, and with vibration this can cause a fatigue fracture of the
wire at that point.

I think best practice is to use tinned copper wire (all the strands
individually tinned during manufacture), with a mechanical only crimp
covered by a short length of adhesive-lined heatshrink tubing.

In the UK, these people: http://www.power-store.com/products/mcw/index.htm
have an interesting range. The stuff they sell is the US-made Ancor range.

It's an expensive way of doing things but should last very well and be
reliable.

Regards,

Jerry Jones

Remove the obvious from my address to reply

"Jack Erbes" wrote in message
...
Meindert Sprang wrote:

This is not a myth or a point of argument. It is the truth. I learnt it
at
school that solder 'flows' when stressed in cold condition. And my
personal
experience proves me right too.

Almost everything "flows" under pressure. I like to think of the
process as the material being swaged or formed.

Doesn't the flow stop at some point in the process as the pressure
relaxes? After the crimp is made, a pressure equilibrium should develop
that is the point where the two pressures (the clamping force from the
terminal and the "flow" in the solder) stabilize.

There's a huge difference in flow between copper and solder. The equilibrium
with solder is on of very low pressure.


Anyway, I generally always tin stranded copper wire before I crimp a
terminal on. Have been doing it for years, and have not had any
systematic or recurring problems because of it.

Luck, I guess....

If you can give me a reference that states that tinning stranded bare
copper wires before crimping a terminal on is a bad thing to do I'll
reconsider my ways. Otherwise we are entitled to have differing opinions.

I cannot give you a reference, but I a professional installer told me that
in the Netherlands and the EU it is prohibited to tin wire before crimping.
And I wouldn't be surprised if the UL also has a similar regulation about
this.

Meindert

"The Floating Bear" wrote in message
. uk...
In article ,
(Jack Erbes) wrote:

tinning stranded bare
copper wires before crimping a terminal on is a bad thing to do

I have been told that it acts as a stress raiser at the point where the
tinning ends, and with vibration this can cause a fatigue fracture of the
wire at that point.

Correct. That is also a reason why regulations prohibit this.

Meindert