"Lynn Coffelt" wrote in message
...

"capt-dia" wrote in message
oups.com...
I am about to purchase a depth sounder to replace the old one[s]. I
have two transponders in the bottom. One at 50hz from a Furuno/Kobel
and another 200hz (???) that belonged to a Gemtronics. What are the
chances that they will work with a new sender/display unit.

Making a couple of assumptions here, one that the two transducers in
your hull are still in good shape, and the second that you are not trying
to
run more power to those transducers than they are capable of handling,
then
chances are pretty good that they will operate fairly well.
Just how well will depend on the transducer matching network on the
new
machine and the type of transducer cable on the old transducers. Cables
with
a shielded, twisted pair of wires will adapt to many current machines (200
or 50 Khz, of course) but if the cable is a simple coax cable the matching
is not so likely.
While in the "business" for many years, we always advised the new
machine owner to be sure and anticipate transducer changes may be
necessary,
but it is worth a try to use the old transducer. The Konel/Furuno
transducers were normally pretty high quality, and stand a small chance of
performing better than the transducer provided with the new machine.
Bottom line: It's sure worth a try!

Old Chief Lynn...... been there, done that.


Well said Lynn.
AirMar makes most of the transducers and they put out a nice cross reference
book.
I see the same basic transducer marketed with different connectors/pin outs.
As long as the frequency range is the same and power level is not exceeded.
most transducers can be rewired to work with a different unit. Its when you
get into temperature and speed sensors that things get a bit tricky. Once
again, go to the cross reference book, look at the schematic of the
transducerducer and the cable. Those with a duplexer in the transducer
probably won't work well or at all with a unit designed for seperate cable
wires.
I only know of a few units that allow the operator/maintenance technician to
tweak the frequency to match the transducer. Furuno has this "sweet spot"
tweaking on a few of their units.

Doug K7ABX