Steve I don't know who makes the connector conversion for the other one that you said, but you can always cut the connector and wire the standard connector in. However, I know only a few after market deck that utilizes two antennas (for FM diversify system), if your aftermarket deck has only one input for radio antenna then you should not combine the factory antenna leads to one since it will only degrade the reception. I believe some of Sony high-end models has dual antenna inputs but generally most of the aftermarket decks has only one input. Actually, I don't believe FM diversify feature works significantly better than the traditional one antenna system. That is why not many Audio manufacturers adapt this technology. If your current set up with one antenna does not provide good reception,may be you should try to use the other connector (by cutting it and wire-in the standard connector). By the way, what brand of deck did you put in the car ?