I rigged up the whole system, went up in the air, turned on both devices simultaneously, ,and voilá, IT WORKED! Of course, as some of you already reported, yesterday we had clear skies over most of eastern United States (I am based in North Georgia) with the exception of some scattered storms in western Kentucky that my Nextrad readily picked up as green and yellow bands. Fantastic! Now the challenge is to use this incredible piece of information judiciously and not let it modify our weather related decision making process.
The USB cable is a non issue, I temporarily installed a cheap retractable one that I used in the past with my previous Blackberry. The standard is 5 pin on the miniport side and 4 on the large standard port side that connects to the Ifly GPS. I believe the fifth contact is internally bridged to ground and this is the standard wiring in all cables with this topology. USB is a standard and everyone does it the same way. Next weekend I'll install the unit under the dash with the remote antenna so I can conceal all the cable clutter.
Regards,
JTB