ADS-B Out via slide-in GTX-327 replacement?

For those with a GTX 330 (and a compliant WAAS GPS), Garmin provided a simple (i.e. no new boxes and minimal if any rewiring) ADS-B Out path with the GTX-330ES. I believe that many of us have a compliant GPS (e.g., a GNS 430W), but a GTX 327. How about a slide-in GTX 327 replacement with an easily accessible (if that's possible) extra connection for the GPS signal (rather than using an existing multipin connection, which would be tough to wire into)? Other than that GPS connection, no other changes would be needed (no additional boxes or extra antennas). Am I missing a reason this wouldn't work? I tried to "sell" it to Garmin some time ago, but I couldn't generate any interest. Perhaps someone else?

John Goldsmith, RV-7A

This is not available, probably for much the same reason that the GTN-650 isn't a slide-in replacement for the GNS-430(W). They changed it because they could. Maybe it is to keep all of the avionics shops in their camp by sending them work. Who knows, but the lack of competition in the market allows them to do what they want and charge what they want.

FWIW one option is to replace the GTX327 with a Trig TT31 - the mounting trays are the exact same width & height, but the Trig is about 2 in longer from memory. I made up a short harness with a DB connector to the GTX327 connector & used the Molex connector supplied with the Trig on the other end. The antenna connection was also made with a short pigtail to the existing BNC connector - all made a difficult changeover under the RV-8A panel relatively simple.

John Moody
RV-8A

moodyjr said:

FWIW one option is to replace the GTX327 with a Trig TT31 - the mounting trays are the exact same width & height, but the Trig is about 2 in longer from memory. I made up a short harness with a DB connector to the GTX327 connector & used the Molex connector supplied with the Trig on the other end. The antenna connection was also made with a short pigtail to the existing BNC connector - all made a difficult changeover under the RV-8A panel relatively simple.

John Moody
RV-8A

Click to expand...

In addition, although the original post was about the 327, if you have a King KT76(x) then the Trig TT31 will "slide in" to that tray and function as a basic transponder. You can then later change out to their tray which has a second connector for the GPS connection.

We did that on Widget's plane when he needed to replace his King.

James

The newer TT31's added a serial port on the main connector so changing the rack is not required anymore to pipe GPS data to the unit!

The TT31 costs about $2500.

Rack or Tray

So John I've been studying this, the trays look close but are not the same according to the install manuals. I take it you have done this and the tray is a good fit in the old 327 space correct? Were the mounting holes close or was drilling required?
And for Walt, you are saying the newer models have a DB connector like the 327 so it will just plug in? (I assume pins will need to be relocated)
I'm ready to upgrade once I know what I'm getting into, it appears my 430W has been approved for use with the TT31, and that may not be an issue now anyway for EAB.
Also still looking at the NavWorxs EXP and a transMon as an option. That would also feed wx and traffic to my EFIS and would be less money.
Answers to above questions and comment welcome!
Tim

I believe Walt's comment was wrt the KT76 rack. If it fit the 327 rack that would be great but I don't think so. Walt?

BobTurner said:

I believe Walt's comment was wrt the KT76 rack. If it fit the 327 rack that would be great but I don't think so. Walt?

Click to expand...

The TT31 is a slide in replacement for the KT76A (the most popular transponder ever made). My comment on the connector is you used to have to change the rack to install the extra connector on the TT31 for the serial ports, they added an additional serial port to some unused pins on the main connector so now changing the rack in not necessary unless you need to access additional ports on the 2nd connector.

I did remove a 330 and installed a TT31, it fit perfect. The rack size (H/W) is the same as the 327 so replacement is not a problem as long as you have room for the extra depth.

Haven't checked dimensions

In response to Tim, I have not checked any dimensions, or any other aspect of compatibility with the Trig unit. I'm still hoping to interest some company (Trig?) to have a direct slide-in replacement for the GTX 327 (like the TT31 is for the KT76).

John