video-cam adaptor

On Mon, 14 Jul 2003 21:39:49 GMT, Bonanza Man wrote:
is there an adaptor that'll take the head-set
audio-out of an airplane intercom into
a jack that can be put into a standard
microphone jack in a video-cam.

I made one the quick and dirty way for my big trip.

All I did was stick a big resistor in-line with the audio (actually a
minature potentiometer, so I could fiddle with it). I initially underestimated
the resistance needed (I thought it might be on the order of 5k ohms,
I ended up using IIRC a 470K potentiometer maxed out). I just soldered
the pot to the pin for the intercom jack tip, then the wire to the other
end of the pot. The potentiometer fits inside the jack plug's cover,
and a bit of heat-shrink rubber makes sure the exposed contacts don't touch
the signal ground's pin. So you have


intercom jack

/-|============| 470K |---------------------left channel
/ |-----------------/\/\/\--|---------------------right channel stereo
\ | | jack
\_|============|------------ signal ground --------------------

It worked well. All the parts can be picked up at Radio Shack. I just
butchered a stereo jack extension cable for the camera side, and soldered
it into a nice screw-together large jack for the intercom. It is quick
and dirty; I think the proper method is to have some form of impedence
matching transformer, but I don't know whether such a beast exists that's
suitable for intercom - camera.

I also made a video camera stand which could be quickly attached to and
released. It was basically a shaped polystyrene block (shaped to the
curvature of the glareshield), which was velcroed to the panel. The camera
was in turn velcroed to the top of the polystyrene block. It stayed on
even during some of the severe turbulence I encountered crossing the Sierra
Nevadas (multiple negative-g bumps which made my charts almost hit the
roof) but was quick to pull off by hand. Make sure you don't site the camera
too close to the compass - I did some testing to see where I could place the
camera without causing the compass to move.

--
Dylan Smith, Castletown, Isle of Man
Flying: http://www.dylansmith.net
Frontier Elite Universe: http://www.alioth.net
"Maintain thine airspeed, lest the ground come up and smite thee"