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Replace the GTX 327 with the GTX 355

Westerhuis

Active Member
Hi

Hope those at KOSH got in and are enjoying the show.

I’m at KOSH and I’m thinking to take advantage of Garmin GTX 335 package deal that includes the WAAS GPS.

I’ve spoken to a few vendors to find out how big a job it really is to change the two. I get super mixed messages. I appreciate it depends on my current set-up etc. But assuming I’m capable of mounting the GPS receiver and routing the coax, how much more technical work needs doing.

I already have a Garmin 696 in my panel. Could my new WAAS GPS aerial feed both the 696 and transponder?

Mind you, I’m a complete novice when it comes to wiring and avionics.

Thanks

Rogier
 
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Rogier,

The short answer to using the 355 GPS for the 696: No

The tray for the 355 is different than the 327 and connectors are also different, so you'll be pulling all the 327 stuff out except for its wiring to the back of the tray. Your altitude encoder may be able to stay. Check the 355 documentation for requirements.
 
Roger. Why not keep your nice functional GTX 327 and just add a GDL-82 or a uAvionix echoUAT to your bird? The GDL-82 won't even require another bottom antenna. The echo will. If you don't have a WAAS navigator for position you will need to add a dedicated GPS antenna. Usually under the cowl on a shelf bracket. Keep what you have and save tons of money.

While at the show look at the following UAT ADS-B out solutions in no particular order:
Garmin GDL-82 (add on)
Sandia Sentinel (transponder replacement)
Freeflight Rangr Lite (add on)
uAvionix echoUAT (add on) - I prefer the one with the SkyFYX-EXT integrated GPS source/antenna.

Jim
 
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I am in the same boat. I wish I had my 327 at Osh to take advantage of the update as mine is too old to work directly.
 
Thanks all. I did consider that option but I need a transponder that I can use in Europe in due course, so this would serve two purposes at one.
 
I am in the same boat. I wish I had my 327 at Osh to take advantage of the update as mine is too old to work directly.

The 327 is NOT too old to work with the GDL82 as the 82 does not depend on the software. Only the embedded code found in the antenna lead. Your GTX 327 software level only matters if you plan on using a GDL-88 or perhaps a Freeflight Rangr with it's serial interface.

And Westerhuis. Yes. If you plan on mainland Europe then you will want 1090ES out and not UAT. The rest of North America doesn't require 1090ES (and don't let the FAA or Garmin tell you different).

Jim
 
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Last year I swapped out my old 330 (non-Es) for the 335 with gps. I purchased it through Steinair and had them make a conversion cable for me. It wasn?t too costly (around $100) and greatly simplified the installation process. SteinAir was also very helpful with the programming changes that were required to make sure my 430, GRT EFIS and new 335 all played together well.

I?m definitely not great with wiring but Steinair and this forum can get you through any installation issues you might encounter.
 
Does anyone know if there is enough space behind the RV-8 instrument panel to contain the 1.3" longer 335?

I have a GTX 327 as well and I'm wrestling with the two options:

1. GDL-82

2. GTX 335

the GDL 82 seems like a lot more work. And more maintenance to keep the software upgraded. Plus in the future I intend to do a thorough panel upgrade and it might be nice to have something like a 335 to begin with.
 
Saville,
Just put the GDL-82 in my 8 which has a Garmin GTX-327 transponder. No complaints so far and about half the cost of the GTX-335.

To answer you question on the depth It looked to be at least 2” clearance behind the GTX-327. Didn’t measure it and going from memory.

Personally think the GDL-82 was less work then a new tray and wiring for the GTX-335. Mounted the GDL-82 on the rear bulkhead for the forward baggage compartment. Unplug cable from transponder and plug into GDL-82. New 2’ long cable from the GDL-82 to the GTX-327. Minimal wiring positive and negative 12 volt. Only a couple more wires if you want the ADS-B out light and and an anonymous switch. Not sure what you mean about software upgrades.

Contemplated the same scenario you’re doing right now and chose the GDL-82 route for ease of install and a lot less cost.

ArlingtonRV also did similar install on his 8. Here’s a link to his thread with some phots.
http://www.vansairforce.com/community/showthread.php?t=167777
 
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The 327's have been around a long time, some are pretty old, so you decide if it's worth it or not to replace the transponder with a new unit.
If you have an old KT76A, Narco, etc. it's a no brainer.

GTX335 - $2995
GDL82 - $1795
 
The 327's have been around a long time, some are pretty old, so you decide if it's worth it or not to replace the transponder with a new unit.
If you have an old KT76A, Narco, etc. it's a no brainer.

GTX335 - $2995
GDL82 - $1795
 
And Westerhuis. Yes. If you plan on mainland Europe then you will want 1090ES out and not UAT. The rest of North America doesn't require 1090ES (and don't let the FAA or Garmin tell you different).
Might be worth noting that the "rest of North America" isn't just "America". Canada's ADS-B system will only use 1090ES at this point...
 
Might be worth noting that the "rest of North America" isn't just "America". Canada's ADS-B system will only use 1090ES at this point...

Which is one reason I'm considering the 335 as opposed to the GDL 82. I just may want to fly to Canada.
 
GDL-82 vs GTX-335

To G3XPERT and all

''Might be worth noting that the "rest of North America" isn't just "America". Canada's ADS-B system will only use 1090ES at this point...''

I was thinking of installing a GDL-82 ''978 UAT type ''(already have a GTX-327) but Ron's Post got me thinking about our upcoming Space Base ADS-B here in Canada which will be on 1090ES so I'm wondering if a 335 might be a better choice and if it will work with a Space Base system vs a Ground Base type....

Any idea, info...inquiring mind like to know before spending lots of $$$:confused:

Thanks

Bruno
[email protected]
 
Can anyone tell me what the all up required depth behind the panel that is required for a GTX 335, the Altitude encoder, all plugs in is?

I need to determine if the space between the RB-8 instrument panel and the rear bulkhead of hte forward baggage compartment is sufficient.

I looked through the GTX 3X5 installation manual and I didn't see a value.


thanks!
 
Can anyone tell me what the all up required depth behind the panel that is required for a GTX 335, the Altitude encoder, all plugs in is?

I need to determine if the space between the RB-8 instrument panel and the rear bulkhead of hte forward baggage compartment is sufficient.

I looked through the GTX 3X5 installation manual and I didn't see a value.


thanks!

Hello,

10.05" from front of rack (front of instrument panel) to back of main connector. The encoder does not stick out further than the main connector.
This is from the Rev. 10 TSO installation manual.

You will need a little more space for wiring.

Thanks,
Steve
 
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Hello,

10.05" from front of rack (front of instrument panel) to back of main connector. This is from the Rev. 10 TSO installation manual.

You will need a little more space for wiring.

Thanks,
Steve

Yeah I had the dimension to the back of hte main connector from the docs. But I was wondering what is required for the wiring - how much is "a little more"?

Also I was wondering if the altitude encoder extended the distance.

Thanks
 
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