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

"engsol" wrote in message
...

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.

Indeed, that's why any decently designed device should have some form of
limit to the risetime, which is not hard at all. We simply put an RC network
on each dataline. But also having galvanically isolated inputs, which is
dictated by the NMEA standard, will ensure a proper balance in both wires of
an NMEA connection, ensuring minimal radiation. The problem is however, that
many manufacturers try to cut corners here.

Meindert