i am currently running a Nobeltec navigation software on my Fishing Vessel and i need some help..

How can i Connect Directly From GPS to PC Comport...i am Connected right now to my PC from my Furuno GP31 and i am getting an erratic screen and i keep getting a Position ID has changed from ID Gp to Com 1 Warning...warning keeps coming constantly and i cant even make routes cause my Boat on my screen is jumping off the charts..

I have another GPS antenna which is sitting Idle and i was wondering how i can hook it to a 9 pin comport Plug..will it work or how can i get it to work.....

any help you can give me would be greatly appreciated....

Peter ( ThunderHawk Fishing Vessel )