Built In Ducers

Built in transducers in trolling motors

The sonar unit is a transceiver, transmits and receives sound from an antenna.

The transducer therefore is just an antenna and the quality of the in and out is directly connected to that antennas ability to do its job.
If you have ever bought or used a C.B. radio you are using a transceiver. When you bought the radio it didn't come with an antenna, that had be purchased separately.

The antenna you purchased has to do with the application you need. Once purchased you take the radio and antenna to a C.B. shop and have the S.W.R adjusted so that the antenna is tuned to the output and input of that radio. The antenna then is line balanced, which gives you the best performance the radio is capable of.

The key word here is line-balanced. If you don't get the antenna line-balanced the the radio will still send and receive but not very well. You won't get out as far and you won't hear a lot of return signals. Prolonged use of an unbalanced antenna may cause your radio over time not to work at all.

Transducers that are not line-balanced to your sonar unit will have the same effect.

Prolonged use of a transducer may have the same result as the C.B. radio antenna.

My advice is to use a transducer mounted to the trolling motor that is the manufacturer line balanced antenna.  This will insure that you will send with full power and receive all the signals your unit is capable of. 

Unless you know the built in ducer is line balanced for the manufacturer’s sonar that you are using, don’t trust it.  200kz ducer is the frequency it broadcasts and waves at.  This does not mean the line is balanced.

I recommend that you use the manufacturers transducer to insure the quality of the broadcast and receiving capabilities of your unit.