"Gert Been" wrote in
:

Ehh, talking about "Decent" multiplexers: decent multiplexers have
isolated inputs, yours don't.

I just connected one of yours to a differential NMEA talker output. I
can
now hear all NMEA data on my SSB!!

While trying to find out what's wrong, I found that all inputs on your
multiplexer have the B terminals connected to ground!!! NMEA inputs
are supposed to be isolated. Your grounded B terminals on the inputs
effectively short-circuit any properly designed talker. Was it that
hard to add 50 cents worth of optocouplers?

Gert



This is one of my pet peeves with most manufacturers. STupid Icom's really
expensive M-802 uses a BNC RF connector that only has ONE WIRE and ground
to hook the NMEA data to the transceiver for DSC/GMDSS GPS input. They
should all be HUNG! If everything had a balanced line like NMEA was
designed for, I could probably transmit on HF without tearing up the whole
boat's NMEA network....(d^

"Larry W4CSC" wrote in message
...

This is one of my pet peeves with most manufacturers. STupid Icom's
really
expensive M-802 uses a BNC RF connector that only has ONE WIRE and ground
to hook the NMEA data to the transceiver for DSC/GMDSS GPS input. They
should all be HUNG! If everything had a balanced line like NMEA was
designed for, I could probably transmit on HF without tearing up the whole
boat's NMEA network....(d^

I agree completely. NMEA should have simply revoked membership of anyone not
adhering to the standard. The NMEA-0183 spec is very clear on the naming of
the terminals, what signals they should carry and the required isolation on
every input. So if everyone adhered to the standard, connecting NMEA would
have been as easy as connecting a ligthbulb.....

Meindert

"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;

"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

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

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

"Doug Dotson" dougdotson@NOSPAMcablespeedNOSPAMcom wrote in
:

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

Doug



There aren't any "moisture proof connectors" on any NMEA crap I ever
had....just wires hanging out of a box or screw terminals on a box....