I have a Helix unit on the bow and a Solix unit at the console. I have a Terrova trolling motor that I would like to add the Link system to. I would also like to add the 360 imaging transducer on the stern linked to the Solix unit. To add the 360 to the Solix will I need to add an external GPS antenna with heading sensor? Is the external GPS with heading sensor needed for the Link system too? The systems are not networked at this time and I was told when I purchased them they will not network well. Only a few programs between the units will work together. At least that is what I was told. Any better information on the networking ability of these two units? If the external antenna is needed any info on which one?