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Old December 4th 03, 10:01 PM
David Lesher
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Back in the "good old days" when I was an avionics tech, they HAD to
put things in the back; the equipment was just too big to fit it all
behind the panel.


The equipment rack in the back of your average Cessna/Piper is no
heaven for equipment. It vibrates just as much and it is actually
hotter than behind the panel. Remember, there are no vents back there
while up front you have cabin vents.


But you can easily have ventilation. You don't need outside
air; a few boxer fans will help a great deal. The big thing is you
have volume and *access*. The big issue I see is protecting against
cokes spilled on/through the seat.

Most of the problems with the old MK-12 solid state inverter power
supplies and the AT-5 transponders were due to the heat and vibration
in the back.


We're talking an order of magnitude more heat in a MK-12 inverter
than for a current whole stack, I bet... I seem to recall those even
used geranium transistors...

Can't see why vibration is worse under the rear seat; only that the
panel has mounts. So, put stuff on mounts.

Running cables of any kind from the back to behind the panel is also
highly labor intensive when done correctly.


Agreed. But one real plus is fiber, even mil-spec "tank-proof" fiber,
is tiny as compared to the ahem equine reproductive equipment it
replaces here. (I installed LOTS of those in police cars years ago..)

And you end up running coax from each antenna, mike/headphone/etc
up into a very tight location where you work by feel....

Fiber all avoids ground loops as well. I could see a audio panel
with a front panel for control, a knee-level jack panel for
mikes/headphones/PTT/CD player in, and a 2nd in the rear for those
passengers.

While you could replace a lot of the wiring with a fiber optic data cable,
you still have to run power back there and you still have to keep the
cables protected and out of the workings. Plus splicing and putting
connectors correctly on fiber is a pain in the butt.


I'd buy connectorized flexible duplex jumpers. But yes, you'd need to
run power there. Good place for the avionics master contactor.



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