Archive for December, 2009

Antenna wiring

Saturday, December 12th, 2009

Good grief, has it been a month since I updated this thing? I've been trying to work on the airplane a little bit here and there, but between holiday travel, work projects, and cold weather, things have been pretty slow in the airplane factory.

I have, however, managed to get the previously installed antennas on top of the fuselage all wired up. Four lengths of RG-400 coax run down from the panel, through the spar, and back under the floorboards. They penetrate the F-706 baggage bulkhead via snap bushings, then run back and up the F-707 bulkhead protected inside plastic conduit.

I drilled small holes in the J-stringers so I could attach the conduit with tie wraps. On the left side of the fuselage, I used a piece of rubber tubing and some tie wraps to prevent the conduit from chafing on the static line.

The conduits run up either side of the F-707 bulkhead – more small holes and tie wraps – and then the coax emerges to connect to the antennas.

Two wires go forward to connect to the WAAS GPS antennas – one for each GNS 430W. I riveted little tabs of scrap aluminum to the lower flange of the F-787 stiffener, so I could secure the wires with adel clamps. Meanwhile, two more runs of coax go through grommets in the bulkhead and connect to the combo GPS/XM antenna that's just aft of F-707.

Here's another view, looking up from [my very uncomfortable position on] the floor. In this picture, the nose of the airplane is to the left.

Up at the forward end, the primary display unit gets a GPS connection, and the multi-function display gets an XM antenna hookup. Each 430W gets a GPS antenna connection too, although I forgot to take a picture of that.

Not surprisingly, the G3X GPS receiver can get a fix even inside my garage with the doors closed. With a good antenna and a strong receiver, you can't lose.

This doesn't look like much, but it took two days' worth of crawling in and out of the airplane to finish.