It isn't normal to use the dual freq CHIRP transducer with the single freq CHIRP sounder. I understand what you are suggesting but the GP1971F is not a commercial sounder where you can manually select the transducer sweep freq or power. The power and freq setup is pre-programmed for the listed compatible transducers, ONLY. Using the low side as an example, your only choice in the software is a 300w transducer. Also you have no control of the sweep bandwidth because the rated transducer can go as high as 75khz, and the TM265 isn't rated that high you will end up with reflected signal at the sounder which might cause damage. I don't think you wish to damage the transducer or the sounder. I wouldn't recommend it. That transducer is more appropriate for a TZT3 sounder or the DFF1-UHD.
