Has anyone had any experience with cutting and splicing the transducer
cable for recent vintage like LMS320 lowrance fish finders? I am
contemplating doing this so I don't haveto cut such a big hole in hull
to run the connector thru. Related to that if you cut the cable what
kind of wiring is in there for the actual transducer?

Is it a shielded twisted pair or is it coaxial like
the older ones. I am thinking of using one of my older transducers
for another location but if the new units used the balanced twisted
pair shielded cable then it probably wont' work very well.

BTW, so far the LMS320 looks like a quality piece of equipement.
Certainly a helluva improvement over my old Raytheon or Humminbird not
to mention my old paper chart.

tks
WA5NGP

Every manufactures manual/instructions I've ever read state DO NOT CUT THE
TRANSDUCER CABLE!
S/V Express 30 "Ringmaster"
Trains are a winter sport

Horsefeathers. I've cut every made-up cable I ever installed and the
sonars work just great! There's two new, but spliced, cables aboard
Lionheart right now. Both sonars work fine because they are on
different frequency bands.....96 and 200 Khz.

Boring out a huge hole just to fit a pre-made cable connector that's
7/8" across is crazy!

But, in defense of this splicing, do NOT just splice the wires back
together with butt connectors like you would the masthead light.
splice each conductor carefully by soldering it, then insulating it as
you go. Work your way out to the shield, the REAL issue here. When
you get to the shield you'll have a bundle of insulated solder
connections. I like to stagger mine so it doesn't make a big bulge.
Wrap the bundle with foil tape, not like you use electrical tape but
with tape that's wide enough to lay under the bundle and overlap the
bundle in a long seam parallel to the wires. Now wrap the drain wires
hanging out around the foil tape making as much contact with it as you
can. This re-creates the original shield around the signals in the
original cables. Coat the connection with a thin layer of sealant
like 3M 4200 and slide the shrink tubing over it all and heat it to
shrink tight, making a watertight connection forever.

You've recreated a shielded connection the sonar pulses won't escape
to trash your radios every 200 Khz up the dial. The sonar will work
just as good as ever and the boat WON'T be full of ugly big holes that
need sealing.

If your sonar cable is already butt spliced but unshielded, all is not
lost. Simply unconnect the shield drain wire splice, and wrap the
bundle of butt splices with the foil tape. Solder on a few inches of
extension to one of the shield drain wires and wrap that around the
foil tape to get a good, tight connection. Then, seal it up like
above and use electrical tape to cover up the sealant. It's shielded,
now, too.

If the sonar's working good and the radios aren't trashed with pulse
noises, LEAVE WORKING SYSTEMS ALONE and forget them!! No sense
creating more problems when there aren't any. Go fix something
broken!



On 08 Oct 2003 04:23:15 GMT, (SAIL LOCO) wrote:

Every manufactures manual/instructions I've ever read state DO NOT CUT THE
TRANSDUCER CABLE!
S/V Express 30 "Ringmaster"
Trains are a winter sport


Larry W4CSC

3600 planes with transponders are burning 8-10 million
gallons of kerosene per hour over the USA. R-12 car air
conditioners are responsible for the ozone hole, right?

Larry, I'm with you. As a ham I've spliced coax antenna cables for
years and did everything possible to keep the impedance discontinuity
minimized and I'd never use those butt connectors, always solder and
use heat shrink and stagger the connections to minimize the lump in
snake. I'll see if I can find that 3M stuff. Sounds like something
good to have around the garage.

Anyway, what will I find when I cut it.? Is the transducer cable a
shielded twisted pair or is it a simple coaxial cable?

Don
WA5NGP

The Garmin 185 cable is three #18 wires in a foil shielded cable.
It's nothing special, just plain old cable. The shorter it is cut,
the better, of course, for both the transducer and the radiation
tearing up the radios......



On 8 Oct 2003 07:50:51 -0700, (Don WA5NGP) wrote:

Larry, I'm with you. As a ham I've spliced coax antenna cables for
years and did everything possible to keep the impedance discontinuity
minimized and I'd never use those butt connectors, always solder and
use heat shrink and stagger the connections to minimize the lump in
snake. I'll see if I can find that 3M stuff. Sounds like something
good to have around the garage.

Anyway, what will I find when I cut it.? Is the transducer cable a
shielded twisted pair or is it a simple coaxial cable?

Don
WA5NGP


Larry W4CSC

3600 planes with transponders are burning 8-10 million
gallons of kerosene per hour over the USA. R-12 car air
conditioners are responsible for the ozone hole, right?

Yea, don't do it just coil up the excess cable. Why would you want to cut
it in the first place? The sounder will not work properly if you shorten
the cable.
Ed
"Don WA5NGP" wrote in message
om...
Has anyone had any experience with cutting and splicing the transducer
cable for recent vintage like LMS320 lowrance fish finders? I am
contemplating doing this so I don't haveto cut such a big hole in hull
to run the connector thru. Related to that if you cut the cable what
kind of wiring is in there for the actual transducer?

Is it a shielded twisted pair or is it coaxial like
the older ones. I am thinking of using one of my older transducers
for another location but if the new units used the balanced twisted
pair shielded cable then it probably wont' work very well.

BTW, so far the LMS320 looks like a quality piece of equipement.
Certainly a helluva improvement over my old Raytheon or Humminbird not
to mention my old paper chart.

tks
WA5NGP