What's new
Van's Air Force

The definitive Van's Aircraft support community! Buying, building or flying an RV? Join our exclusive family of mentors and enthusiasts!

Adding the GPS 175 to the G3X system in an RV-12is

N8DAV8R

N8DAV8R

Well Known Member
Friend
I wanted to start a thread that may hopefully serve as a roundup for information on adding the GPS 175 to an RV-12is with the G3X system. Especially the dual PFD/MFD system, but the configuration is similar enough the PFD only should fit in. Ideally this thread will on-topic with technical information. I know there are several builders/owners who plan this addition. Please avoid commenting on the legal aspects of IFR/IMC or the merits of GPS only navigation, those are important topics but they are covered heavily in other threads. If you have already done this install, please jump in and give some advice. If you are working on it or planning it now, offer up what you know so far.

I'm finally getting around to starting my install. I feel like I have a decent high level grasp of the wiring needs. Now that I'm actually starting on the wiring and looking closer at the diagrams for both the VFR and IFR packages from Van's, it's getting more clear and seems even easier to integrate than I originally thought. That's great, but it also feels a little bit like falling into a trap! Sanity check or alternatives on a few concepts is a good place to start.

A few things specific to installing in this context that are good to discuss and may be blind spots but probably have simple answers. Obviously there will be more but these are some of the things specific to adding this equipment to a G3X RV-12iS.

  • Replacing GPS-20 with GAD-29, using some of the existing wiring by moving pins to the new back shell
  • Power for the 175 taken from the same location that would power the GNC in the IFR package
  • GPS antenna options - Needs may vary a bit based on specific configurations.
  • Center panel modifications and the radio stack. Amadeus has some posts in the 'mods' thread that provides a good example of how things could fit.
  • Necessary software re-configuration that may come as a result of the new GPS source as well as configuring the 175/PFD.
EDIT TO ADD: Thread with question regarding the interconnect diagrams and some inconsistencies between Garmin and Van's recommendations.





A link to the post from Amadeus, this install was done by an avionics shop so it's a great example but with limited technical detail.

Modifications that you have Made to your RV-12 after Certification? E-LSA Only!

Maybe, Jim —- or maybe he REALLY made some mods!😝
vansairforce.net
 
Last edited:
N8DAV8R said:
I wanted to start a thread that may hopefully serve as a roundup for information on adding the GPS 175 to an RV-12is with the G3X system. Especially the dual PFD/MFD system, but the configuration is similar enough the PFD only should fit in. Ideally this thread will on-topic with technical information. I know there are several builders/owners who plan this addition. Please avoid commenting on the legal aspects of IFR/IMC or the merits of GPS only navigation, those are important topics but they are covered heavily in other threads. If you have already done this install, please jump in and give some advice. If you are working on it or planning it now, offer up what you know so far.

I'm finally getting around to starting my install. I feel like I have a decent high level grasp of the wiring needs. Now that I'm actually starting on the wiring and looking closer at the diagrams for both the VFR and IFR packages from Van's, it's getting more clear and seems even easier to integrate than I originally thought. That's great, but it also feels a little bit like falling into a trap! Sanity check or alternatives on a few concepts is a good place to start.

A few things specific to installing in this context that are good to discuss and may be blind spots but probably have simple answers. Obviously there will be more but these are some of the things specific to adding this equipment to a G3X RV-12iS.

  • Replacing GPS-20 with GAD-29, using some of the existing wiring by moving pins to the new back shell
  • Power for the 175 taken from the same location that would power the GNC in the IFR package
  • GPS antenna options - Needs may vary a bit based on specific configurations.
  • Center panel modifications and the radio stack. Amadeus has some posts in the 'mods' thread that provides a good example of how things could fit.
Click to expand...
Thanks for starting this thread! I'm excited to see others input.
 
One question I would like to pick at a little bit is the physical space and location, assuming the install includes an AP panel like the example linked above. He mentions that the GTR had to be raised in order to make room for the entire stack to fit, at least in that configuration. Second opinions on this would be good. Maybe someone has gone down this rabbit hole. My airplane is away for paint so I'm working a little bit blind but still trying to plan.

Could the GTR be left in place, with the AP panel being installed above it? The AP panel is not very deep and uses a simple clamping install method. Could it fit between the center panel and the LRU transponder that is at the top of the stack? In this configuration there would be plenty room for the 167 to be installed below the GTR in the space where the AP panel previously lived.

If not, does the GTR really need to move up in order to get the AP panel and 175 below the GTR? I have a couple spare center panels and with a test-fit it seems like there is room. Any owners who could verify and/or describe where the interference is?
 
A question that may also impact Dynon Skyview installs: what does one do about the audio output for the GPS 175? On the electrical schematics, I see that there's an unconnected pin labeled NAV AUDIO on the NAV/COM connector.

Does anyone know if there's any restrictions against using these for the GPS 175 audio? If so, how do the audio levels get adjusted in the mixer?
 
Hey Nate (@N8DAV8R),

I don't really have a lot to add since I have a Sling LSA with a GTN650 Xi, but your post reminded me of a YouTube video I watched when I was debating myself on getting a "-12iS"....

Anyway, I remembered correctly, Pedro (the Youtuber in question) indeed added a Garmin GPS 175 to his RV-12 (not "iS); maybe it can help you and others since it's fairly well documented (for a Youtube video, at least).

Good luck!

 
N8DAV8R said:
Could the GTR be left in place, with the AP panel being installed above it? The AP panel is not very deep and uses a simple clamping install method. Could it fit between the center panel and the LRU transponder that is at the top of the stack? In this configuration there would be plenty room for the 167 to be installed below the GTR in the space where the AP panel previously lived.

If not, does the GTR really need to move up in order to get the AP panel and 175 below the GTR? I have a couple spare center panels and with a test-fit it seems like there is room. Any owners who could verify and/or describe where the interference is?
Click to expand...
Here is the backside...

pil3.jpg


pax3.jpg
 
Original post updated with a link to relevant question.

GPS175 to G3X Interconnect Questions

I'm adding a GPS 175 to my completed RV-12is. I have a pretty good grasp on the wiring that I need to do but I have some questions that fall in the easy/dumb category. Being an ELSA -12 builder I didn't have to think through the wiring scheme other than the most basic understanding. Garmin's...
vansairforce.net
 
Last edited:
Can someone post a picture of the shelf you fabricated in the engine compartment to add the additional GPS antenna for the gps175. I know I have seen one here somewhere but I can't find it. I'm at the Avionics SHop getting mine installed today
 
mhailey said:
Can someone post a picture of the shelf you fabricated in the engine compartment to add the additional GPS antenna for the gps175. I know I have seen one here somewhere but I can't find it. I'm at the Avionics SHop getting mine installed today
Click to expand...
Hey Mike (@mhailey), have you checked this thread?

GPS 175 antenna mounting location

I am beginning the installation of a GPS 175 in an RV-6. Does anyone have experience with mounting the GA35 on the glareshield ? I have the Dynon GPS 2020 antenna and ELT antenna mounted aft of the canopy, and don’t want to mount it there. I don’t really want to go in front of the windscreen...
vansairforce.net

I see a few pics there that I think might be useful.

By the way, really happy to see you are using your RV-12iS!
 
rot said:
Hey Mike (@mhailey), have you checked this thread?

GPS 175 antenna mounting location

I am beginning the installation of a GPS 175 in an RV-6. Does anyone have experience with mounting the GA35 on the glareshield ? I have the Dynon GPS 2020 antenna and ELT antenna mounted aft of the canopy, and don’t want to mount it there. I don’t really want to go in front of the windscreen...
vansairforce.net

I see a few pics there that I think might be useful.

By the way, really happy to see you are using your RV-12iS!
Click to expand...
Yes we decided to mount the additional antenna much like the picture in that thread. I’ll post a picture when its fabricated and installed
 
Amadeus said:
So you kept the GPS20A? Does the GPS20A not conflict with the GPS175?
Click to expand...
The GPS 20 is not in any of those pictures. Those are antennas. The GPS20 is a GPS receiver that connects to an antenna, similar or same as either of those. I'm not speaking to his entire installation, but it would stand to reason that one of those antennas connects to his GPS175, the other connects to his GDU(G3X). It's also possible that he has a Dynon system that it connects to and never had a GPS20 in the first place.

See my comments in your other thread. I think you have some of these components and how they were originally installed confused, maybe led down that path by the builder of your plane or the avionics shop that did your installation.
 
Last edited:
N8DAV8R said:
The GPS 20 is not in any of those pictures. Those are antennas. The GPS20 is a GPS receiver that connects to an antenna, similar or same as either of those. I'm not speaking to his entire installation, but it would stand to reason that one of those antennas connects to his GPS175, the other connects to his GDU(G3X).

See my comments in your other thread. I think you have some of these components and how they were originally installed confused, maybe led down that path by the builder of your plane or the avionics shop that did your installation.
Click to expand...
Not confused. Neither of those antenna work with the G3X which is why I could only assume that the GPS20A was left installed. The GA26X is the antenna that connects to the G3X.
 
Amadeus said:
Not confused. Neither of those antenna work with the G3X which is why I could only assume that the GPS20A was left installed. The GA26X is the antenna that connects to the G3X.
Click to expand...
Fair enough based on some reasonable assumptions, but there are antennas in that form factor that work with the GDU like the 55, 56, and 57.

It's also possible that his airplane, like mine, has a GDL-52R. This is one of the oddball configurations with the RV-12. You could end up with 2 WAAS receivers if you also had the XM option. I'm planning to use my 37 antenna in the system via the GDL-52R and use the 36 antenna that came with my GPS 175.

Probably easier to just buy the 26 antenna and plug it in to the G3x than run a new cable all the way to the back where the GDL-52R is, and I'm not sure that the GDL works as a WAAS in that way, it seems more likely that it only feeds a mobile device.
 
Last edited:
Ruready said:
Do you have a metal cowling over the top of that GPS 175 antenna if so is it still working like that I have a Cessna that I'll stick my antenna under the cowling if it works?
Click to expand...
It is a fiberglass cowling over those antennas. Putting the antenna under metal is not going to work well. You can actually see that in the photos above from Amadeus. His shop installed a GPS antenna under the avionics bay cover which is metal, it's not working for him.
 
Amadeus said:
So you kept the GPS20A? Does the GPS20A not conflict with the GPS175?
Click to expand...
First off, this is a single GDU460 10" G3X touch system that is installed in an RV12IS that I purchased from Tango. So forgive me for not being up on all of the installed components as well as I might if I would have done the entire install. Here is a pic just after we opened up the panel. I believe that's the 20A in the back mounted to the firewall. IMG_6516.JPG


I did question the avionics shop on whether or not the GPS 20A and antenna could be removed, and was told that it needed to stay. Perhaps it has something to do with the fact the 20A was the WAAS source for the G3X ADSB? Not sure but maybe someone could elaborate.

Here is a picture later in the day of the Tech building up the structure to support the trays. The stack will be identical to Amadeus's pictures from earlier in the thread.
IMG_6530.JPG
 
mhailey said:
I did question the avionics shop on whether or not the GPS 20A and antenna could be removed, and was told that it needed to stay. Perhaps it has something to do with the fact the 20A was the WAAS source for the G3X ADSB? Not sure but maybe someone could elaborate.
Click to expand...
The 20A is to the left of the backup battery. The avionics shop that installed my GPS175 removed the 20A stating that it was redundant and used the existing antenna that was already installed for the 20A.

N8DAV8R said:
It's also possible that his airplane, like mine, has a GDL-52R. This is one of the oddball configurations with the RV-12. You could end up with 2 WAAS receivers if you also had the XM option.
Click to expand...
I do have the GDL52R and nothing has changed since removing the 20A. XM radio still comes on with the sales pitch and the weather still shows up on the Wx screen.

N8DAV8R said:
His shop installed a GPS antenna under the avionics bay cover which is metal, it's not working for him.
Click to expand...
This past weekend I pulled the GA26X antenna from where it was mounted under the aluminum panel and had it pulled it through the opening of the PFD to dangle in the cabin. Went for two flights and had zero terrain warnings. I will be fabricating a platform for it under the cowling beside the GA36 antenna just like mhailey did pictured above.
 
I picked up the aircraft yesterday, and here is a picture of the completed panel. Now that I have the instrument panel powder coated, I really need to have the panels on the center console done to match.
IMG_6534.JPG
 
You must log in or register to reply here.
Back
Top