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Audio inputs to Garmin GTR200B radio -

T

tonyjohnson

Well Known Member
I have read the posts here about the Garmin 200BT comm radio, which many here use and like. I like the fact that it can act as a "sort of" audio panel in that it an accept audio inputs from other panel devices. It seems that it has two input ports for those devices. My problem is that I have more than two audio sources. I would like to have audio inputs from:
Nav Radio
Area 660 GPS
AV30

I am ok with using bluetooth for Music. I want to leave room for an auto pilot which may produce audio alerts as well.

So, how do I get at least 4 inputs into the GTR200b radio that only has two input ports? The solution may be this simple audio panel that takes 10 inputs, but does not provide for volume control for each input. It would be great to run the inputs thru switches so they can be turned on and off by device. I welcome suggestions.
 

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tonyjohnson said:
I have read the posts here about the Garmin 200BT comm radio, which many here use and like. I like the fact that it can act as a "sort of" audio panel in that it an accept audio inputs from other panel devices. It seems that it has two input ports for those devices. My problem is that I have more than two audio sources. I would like to have audio inputs from:
Nav Radio
Area 660 GPS
AV30

I am ok with using bluetooth for Music. I want to leave room for an auto pilot which may produce audio alerts as well.

So, how do I get at least 4 inputs into the GTR200b radio that only has two input ports? The solution may be this simple audio panel that takes 10 inputs, but does not provide for volume control for each input. It would be great to run the inputs thru switches so they can be turned on and off by device. I welcome suggestions.
Click to expand...
Use the AP60 you pictured, and put switches in line with the audio before it goes to this mixer box.
Exactly what I was going to do on a fellows avionics upgrade... until he decided to get a real audio panel.
 
Several options:
1. Skip the mixer, put a 330 ohm resistor in series with each device (4 total), then connect the other end to an input (two wires to each input). The resistors will keep the devices from fighting each other. The volume will be slightly reduced. If one of the pair is louder, use a bigger resistor (trial and error).
2. Build your own mixer. About $5 in electronic parts. Lots of schematics available (google ‘audio mixers’). Include volume controls, switches, etc., as you desire. You’ll need some modest skill at soldering small parts.
3. Pay the $60 or so for the pre-built mixer. Again, add external switches or volume controls as desired. Note these can be either/or. e.g., my #2 com audio output is ‘switched’ on or off by turning the volume control, no switch (this is similar to the arrangement in the old 152 I learned to fly in, do seems natural to me!).
 
One thing I'd add. If you EVER contemplate having two COM radios, the audio panel is the way to go.
If you look at the Garmin GTR200B installation manual, the dual COM schematic calls out an audio panel.
There's reasons for that, which I won't bore you with. But, You don't need the Garmin $2000 audio panel...
the PS Engineering PMA4000 will do for most all of us.
Dual NAV, Dual COM, and two Aux inputs

Who has ADF, Marker Beacon, SAT Phone, or DME (or is thinking of putting it in a new build)?
Maybe up north... but you could run the ADF input into the "NAV2" on this unit.
IOW, classic audio panels are overkill.
 
FWIW, I am maybe not the most savvy with this, but I did try various resistor combos(as in spending a day swapping them on a breadboard) and couldn't get multiple inputs to balance to my satisfaction... Then I also tried a generic passive mixer and then a generic active mixer with somewhat better results(ie around the $25 price point). Now I have an AP-60 and am very happy with how it mixes. (y) Of note, it does have a IC in it and am supplying all its inputs at line-level and not speaker-level. Possibly all-speaker level would work too(I haven't tried it), but mixing speaker and line level didn't work on my bench tests...
 
blaplante said:
One thing I'd add. If you EVER contemplate having two COM radios, the audio panel is the way to go.
If you look at the Garmin GTR200B installation manual, the dual COM schematic calls out an audio panel.
There's reasons for that, which I won't bore you with. But, You don't need the Garmin $2000 audio panel...
the PS Engineering PMA4000 will do for most all of us.
Dual NAV, Dual COM, and two Aux inputs

Who has ADF, Marker Beacon, SAT Phone, or DME (or is thinking of putting it in a new build)?
Maybe up north... but you could run the ADF input into the "NAV2" on this unit.
IOW, classic audio panels are overkill.
Click to expand...
I was about to jump all over the first line in this post, until I read the last line!
I have no 'classic' audio panel, but instead an intercom with a lot of extra always active inputs, plus a single toggle switch to move the mic and PTT between the two radios. I fly IFR with this set up and don't miss the 'classic' audio panel at all. MB, ADF, who uses these anymore? My local airport with an ILS decommissioned both years ago. Even with the remaining VORs, most (I think - certainly my SL30) radios these days decode the morse code for you and display the ID visually.
 
Bob,
Does your 'toggle switch' move both PTT lines and both MIC lines (pilot & co-pilot) to the 2nd COM radio?
How about the intercom functionality? If you move the pilot MIC to radio 2, do you still have intercom?

That's the area where things started to get messy for the above mentioned upgrade project on an older 6 (not mine).
 
blaplante said:
Bob,
Does your 'toggle switch' move both PTT lines and both MIC lines (pilot & co-pilot) to the 2nd COM radio?
How about the intercom functionality? If you move the pilot MIC to radio 2, do you still have intercom?

That's the area where things started to get messy for the above mentioned upgrade project on an older 6 (not mine).
Click to expand...
The toggle switch is a standard dpdt switch, routing the PTT and mike out lines from the intercom to com 1 or com 2. The co-pilot’s PTT switch on the stick actually activates a small relay inside the intercom, so only the co-pilot’s mike goes out to the com (and only the pilot’s mike goes to the coms otherwise). The intercom runs completely independently of all this. Everyone hears everything, unless they choose not to (if the passengers are yaking during landing approach I sometimes turn my intercom volume way down. Or my wife may turn the com volume down and the music volume up, if she wants to sleep, etc,). Note this setup cannot run ‘split com’ where pilot uses com 1 while copilot uses com 2. I’ve never had this need.
 
Thanks Snowflake. That is exactly what I needed (I think). Hopefully. :)

I’ve sent an email to the seller.
 
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