Archive for August, 2009

Radio connectors

Sunday, August 9th, 2009

At long last, I am finished wiring the radio stack. I removed the backplates from the radio trays and bolted on the connectors and their backshells. Here's an inside view of one of the 430 backplates with connectors attached:

Here it is from the other side… the wire bundles are wrapped with silicone fusion tape to cushion them against the strain relief clamps.

The shield grounds all go to a card-edge connector that mates to a rib sticking out from the backplate casting. Seems to work okay, although it causes all the separate wire bundles to become inextricably tied together. A few product generations later, they switched to a different method of terminating shield grounds that I like better.

One of the audio panel connectors contains a "config module" (the small green thing in this photo) which is a little serial EEPROM that stores airframe-specific configuration data. The idea is that any changes you make to your audio panel configuration stay with the airplane, not the audio panel, so you don't have to re-configure things if you have to replace the unit. Since my overly fancy microprocessor-controlled audio panel requires you to connect a laptop to it to adjust certain settings, this may come in handy in the future.

The config module sits in a little pocket in the cast-aluminum connector housing:

I got the connectors and backplates for both 430s and the transponder installed, but I am stuck on the audio panel connectors for want of a handful of screws. I bet they're on my desk at work. Here you see the new style of connector backshell – it has threaded holes to which you attach the shield ground wires via ring terminals. This is a nicer way to do it, since multiple connectors on the same device can remain separate without their shield grounds getting all balled up.

Riveted transponder doubler

Sunday, August 9th, 2009

Al Stuber put his CH 750 project on hold long enough to drop by and hold the bucking bar against the belly skin while I crawled inside and backriveted the transponder doubler. Thanks Al.

The brown discoloration in the above photo is alodine, by the way. Don't want any surface corrosion forming here and messing up my antenna ground plane.

Here's a shot of the transponder antenna bolted to the bottom of the fuselage… nothing to it, just a plastic shark fin thingy:

One more thing checked off the to-do list.