Output from NMEA 0183 to SeaTalkng convertor

[Lew Springer]

Chuck,

Thanks for your response. Unfortunately it did not answer all my questions. I have a SeaTalkng converter powered by 13.65 volts. It in turn powers an RS130 GPS via a backbone. A proper load is at the GPS sensor and on the open end of the convertor. An MFD is also attached to the convertor via a SeaTalkng spur. I know the GPS is operating properly because the MFD receives and processes the position sentences.

When I put an oscilloscope on the NMEA 0183 connections (scope is the only load) I get the results in the attached PDF sketch. This doesn’t look right to me. Is this the expected open circuit output from the convertor? Note that the ve+ voltage is always higher than the ve- voltage. My Icom 604 receiver accepts and displays the proper data.