working split (for the hams here)

I recently learned about working split for pileups.  J38r was working split (duplex) from a dxpedition on an island near Granada. He was transmitting on 28.440 and listening between 5 and 15 kilohertz up. I managed to sort of get him but he couldn't copy well enough to count as a contact. After an hour I gave up and called my neighbor and walked him through setting his radio for working split. My neighbor was able to set his radio up for this but had no luck making the contact either.
He had never done this before and if nothing else, it felt good to teach him what I've learned.
So much for my knowledge of geography. Grenada is the island. For some reason I thought it was on the mainland.