Look for a speciallize shop for communications parts. Some of the places in your area have this stuff but they have minimum charges like 50 or 100 dollars. You might consider getting the extension cable for the e38/39 I mentioned above and splice it to yours. Attach one end to the nav and splice the other to your antenna cut off wire (carefully). Try some place like BMA Parts which I think is in the LA area for a good price. You can find their number on the web.