I have three basic Raymarine instruments: Wind, Speed & Depth.
All of them ST60.
Wires between instruments and trnsducers are very long for my boat.
My question is if I can make them shorter insted of having three big
coils.
Thanks in advance
Mada

Yes, all three cables can be shortened.
I have practical experience from several (10+) yachts,
with the ST60 range.

Regs,
TomS

wrote in message
...
I have three basic Raymarine instruments: Wind, Speed & Depth.
All of them ST60.
Wires between instruments and trnsducers are very long for my boat.
My question is if I can make them shorter insted of having three big
coils.
Thanks in advance
Mada

wrote in news:34dbfff2-33fb-4ab2-86de-4e1782d08c09
@x35g2000hsb.googlegroups.com:

I have three basic Raymarine instruments: Wind, Speed & Depth.
All of them ST60.
Wires between instruments and trnsducers are very long for my boat.
My question is if I can make them shorter insted of having three big
coils.
Thanks in advance
Mada


Sure. Cut them some distance from the plugs OUT OF THE BILGEWATER SHOWER
PLEASE, in some DRY convenient place and put them through a little terminal
strip so you'll be able to test them when, not if, they fail. Don't put
the sonar DEPTH terminal strip close to the others as it will radiate a
bit. If you mount the terminal strip in a little aluminum box grounded to
the ground terminal (shield) of the cable, it reduces radiation that may
screw up your radios from the sonar pulses. Put the sonar in one box and
the other two in a separate box to isolate the sonar noise from the others
that run on low signal levels. Don't let the boxes touch each other
running on separate grounds (shield of the cable).

Got troubles with WIND? Pull the cover off its box and you can easily
measure its voltages and output later on. After you install the
strips/box, measure what the levels are when these units are working,
EXCEPT THE SONAR TRANSMITTER OUTPUT to the transducer. Then you'll have an
idea what's "normal"....put it on a piece of notepad and stuff it in the
box for the poor sap to has to trace the wires...

Thanks a lot.
Mada

Jack Erbes wrote in news:4850ff8f$0$7692
:

I'm thinking that shortening the cable could upset a resonant circuit
and that is not a good thing, right?



I sure hope they're not trying to tune an audio line with 50' of coax....

I've never seen any ill effects of shortening the cable IF you shield the
interconnection point so it doesn't tear up the HF receiver...(c;

In article ,
Jack Erbes wrote:

That may be bad advice Larry.

Airmar is the major supplier of transducers for most of the brands on
the market. And many of the Airmar transducers come with installation
instructions that tell you not to cut the cable.

And they also warn you that doing it will void the warranty.

You can read it about it here in a typical installation guide:

http://www.airmartechnology.com/uplo.../17-006-01.pdf

I'm thinking that shortening the cable could upset a resonant circuit
and that is not a good thing, right?

Jack

Not really relevant in Depth Sounder Transducer design. Most Sounders
at using LOWER Frequencies than 500 Khz, and the difference in cable
length would only be a very small fraction of a Wavelength, at that
frequency.
The REAL Reason for that Statement, is to keep uneducated folks from
messing up the splice, and then asking the OEM, to replace it for Free,
because it doesn't work anymore.
I have spiced thousands of Transducer Cables, over the years, rather
than running a new one down from the Bridge, when replacing a blown
Transducer. It is a LOT cheaper than Hiring a Carpenter, Electrician,
and Shipfitter, just to pull all the Paneling, Raceway covers, etc, to
run a new Transducer Cable. You splice your RF Cables all the time,
Transducer Cables are exactly the same idea, except usually they are
Differential Loads, (Two wires and Ground/Shield) and significantly
lower in frequency. Attenuation in the splice is linearly related to
Frequency, and at sub 500 Khz is NOT a significant loss. SWR is also
not significant unless you cable is a couple of hundred Meters Long.
It is always nice to give the Output Resonant Circuit a Tweak, after
messing with the Transducer, Cable, etc, and peak it up using an
O-Scope across the Transducer Output of the Sounder. That ensures
that your matched to the Transducer Load, and you can also tweak
the first Receiver Resonator for Maximum Return signal at the same time.
Usually it makes less than 1 or 2 DB difference.

--
Bruce in alaska
add path after fast to reply

In article ,
Jack Erbes wrote:

Okay, I guess I just believe too much of what I read in the install
manuals.

But if these *******s that are breaking into homes to rip all the copper
out and sell it for scrap ever get wind of how much wire is coiled up in
the bilges of boats, there is going to be some real trouble...

Jack

Only those guys are so stupid, they would try and get the Transducer,
while they are there, open a hole in the hull, and die trying to
get out of the bilge, before the vessel SANK.....

--
Bruce in alaska
add path after fast to reply

Bruce in alaska wrote in news:fast-CAEC19.11221012062008
@netnews.worldnet.att.net:

Not really relevant in Depth Sounder Transducer design. Most Sounders
at using LOWER Frequencies than 500 Khz, and the difference in cable
length would only be a very small fraction of a Wavelength, at that
frequency.
T

I think the manufacturers are not recommending it because of the molded
plugs and tech support headaches created by some non-technical boaters
cutting the wires then screwing up putting the shortened wires back
together without shorting the cable and blowing the transmitters.

I can see their point.....(c;

It's more a human problem than anything technical....