wrote:
Guys, I am trying to figure out how to extend the cable for the 396
antenna so i can route the cable in the right way... Have you guys
seen a mini usb extension cord or connectors?

Garmin sells an extension cable:
https://buy.garmin.com/shop/shop.do?pID=1237

USB connectors are not particularly weatherproof, so you probably want
to make sure all the connectors are inside the plane. You may also want
to put a piece of heat-shrink tubing over the antenna plug-extension
socket connection to make sure it stays plugged in.

I don't think you can get there with standard "computer" cables.
Digging around a little, USB 5-pin Mini B extension cables (F-M) don't
seem to exist. At first I thought you might be able to make one with
the available cables and adapters, but now I don't think that will
work. The reason is that standard USB cables have 4 conductors plus
shield, and the connectors have 4 pins plus shield. The mini USB
connectors have 5 pins plus shield, but the cables only have 4
conductors plus shield. The fifth pin is jumpered at the connector to
tell the device how to behave. However, the manual for the GXM 30 says
that the cable is 5 conductors plus shield. So, at best, using
"computer" USB cables wouldn't work, and at worst, it would fry your GPS
and/or your antenna.

Another option would be to buy a 5-pin Mini B plug and a 5-pin Mini B
socket and make your own extension cable. The problem with this is that
5-pin Mini B plugs don't appear to be available to mortals.

Or can I simply cut the cord and splice in a foot or so?

You could, but it would probably be better to use an extension cable.
You'd have to be comfortable with soldering some pretty small stuff -
you'd need to make 10 28 AWG splices, plus two splices for the shield.
It might be slightly easier to cut the cable and install connectors that
mortals can buy on the two cut ends, and then use a ready-made extension
cable between the two connectors. Of course, any of this would void the
warranty on the antenna.

Matt Roberds