Cockpit Audio wiring (hyjacked from "gear warning")

"Mike Lindsay" wrote in message
...
In article DdqdnYPHoYf1J-benZ2dnUVZ_v
Snip-------
We put in a new vario this year, the only snag was we had
nowhere to put the speaker except behind the panel. We thought we could
do with a bit more audio. I remembered our radio, a Dittel clone, has an
input for an intercom. We fed the audio from the vario into the radio,
and now we have all the volume we need.


--
Mike Lindsay

Mike, that's interesting. Did the radio squelch the vario audio when
transmitting and receiving?

A quick check of my Microair 760 manual shows that Pin 14 is "Music in" on
the DB15 connector. Now, I'm not going to connect a $1000 vario to a $1000
radio without some specific guidance from the respective manufacturers but
that's a cool idea. The audio from the little pizeo squeekers that come
with the Borgelt instruments isn't that great (Even Mike B suggests that
there are better speakers.) and it would be nice to squelch the vario audio
when using the radio.

Bill Daniels

This is probably one of the best suggestions I've heard in a long time
on RAS - feeding the vario audio to the radio intercom input so that
it's squelched when transmitting. It would be a lot easier for my old
ears to have the speaker behind my head double for this function rather
than the wimpy vario speaker in the panel.

Mike

"Mike the Strike" wrote in message
oups.com...
This is probably one of the best suggestions I've heard in a long time
on RAS - feeding the vario audio to the radio intercom input so that
it's squelched when transmitting. It would be a lot easier for my old
ears to have the speaker behind my head double for this function rather
than the wimpy vario speaker in the panel.

Mike


Been RTFMs again.

The B50 expects to see an 8 ohm speaker load and the M760 expects to see
100mw at 600 ohms on the 'music' input. Any 'sparkies' with an opinion on
how to match up these devices?

Bill Daniels

In article , Bill Daniels
writes

Been RTFMs again.

The B50 expects to see an 8 ohm speaker load and the M760 expects to see
100mw at 600 ohms on the 'music' input. Any 'sparkies' with an opinion on
how to match up these devices?

Bill Daniels

I'm not a sparkie, but if you have an 8 ohm speaker it will have
about 0.5 volts of audio across it when sounding. At this low impedance
that will be enough for the radio. It wouldn't work if you fed a high
impedance output into a low impedance input, but its fine this way
round.

My calculation suggests for full output from the music input
you'd need getting on for 8 volts of AC but I expect that'd be enough
volume for a disco.
--
Mike Lindsay

"and it would be nice to squelch the vario audio
when using the radio. "

Why?? One of the great pleasures of cross country is to key the mic
from a 10k thermal when you know your competitors looking at the dirt.

Andy

"Andy" wrote in message
oups.com:

"and it would be nice to squelch the vario audio
when using the radio. "

Why?? One of the great pleasures of cross country is to key the mic
from a 10k thermal when you know your competitors looking at the dirt.

Andy



Exactly, Andy!!!



How many times have you postponed a radio call a few seconds until you
were in the "hot" side of the thermal so everyone could hear a faster
pitched audio vario? ;-)



Larry

On Fri, 18 Nov 2005 08:04:22 -0800, Mike the Strike wrote:

This is probably one of the best suggestions I've heard in a long time
on RAS - feeding the vario audio to the radio intercom input so that
it's squelched when transmitting.

No, it would spoil the fun. Then you can't center a decent thermal, push
the ptt and let your buddies listen enviously to a high pitched
"tweet-tweet-tweet" for a few seconds before you start blabbing into the
mic.


Ian

In article ,
"Bill Daniels" wrote:
The B50 expects to see an 8 ohm speaker load and the M760 expects to see
100mw at 600 ohms on the 'music' input. Any 'sparkies' with an opinion on
how to match up these devices?

If the B50 provided an unbalanced output (one side of the speaker is
returned to ground, just hook them up. It will work fine.

If the B50 puts out a balanced output (speaker floats, not connected to
ground), go by your neighborhood Radio Shack ("You have questions, we
have blank stares") and get a 273-1380 audio output transformer. Hook
the 8 ohm side to the B50 and one-half the 1K ohm side to the M760.

What an excellent thread.
Mark's Radio Crap transformer and a couple of resistors, and you're
laughing!
The vario automute function has a side benefit of keeping us off the
radio until we have the thermal centered at 14 knots, allowing
concentration on silly things like not hitting anybody else on entry.
Alle ist wunderbar in segelflugland.
Jim

If cutting the vario when the mic is keyed is the objective, could the
PTT be wired to cause a relay to open the vario speaker circuit? Then
the technique could be used with any radio?