G3X and all the GPS

[rpigeek]

Doing an installation for G3X that has a GDU 460, G5, GDL 52R and GPS 175 (w/GAD 29) and trying to sort out what relays GPS signals.

The GPS 175 will have an external TSO compliant GPS antenna. The G5 has an internal GPS, so does the GDU 460 and you can add an external antenna to the GDL 52R.

1. If I have all these GPS signals can the GDL 52R get GPS data relayed from the GDU 460, G5 or GPS 175 for when an iPad connects to the GLD 52R via Bluetooth without an antenna on the GDL 52R?
2. Are the internal GDU 460 and G5 GPS antennas good enough or should I plan to add a 2nd non-TSO GPS antenna? In a GPS 175 failure.
3. If I add an external non-TSO antenna to the GDL 52R will it relay to the GDU 460 and G5 as I assume it'll be better than the internal antennas? In a GPS 175 failure.
4. Is the MapMX RS-232 for to/from the GPS 175 just for backup? I'm assuming the GAD 29 is broadcasting the similar info to the Canbus over the A429.

Planned System Diagram for reference. Also asked g3xpert, but awaiting a replay / call. Thought to ask here as well.

 

[BCP Boys]

I'll try to answer some of your question -
1. GDL 52R has 3 antenna connections if I'm not mistaken - You will definitely need an an antenna on the belly of your plane for ADSB portion of GDL 52R. Personally I have the GDL 52 and the the built-in antenna works just fine for ADSB but for the R model, I'm guessing you will be hiding it behind the panel somewhere, you will certainly need an antenna. You will also need a Sirius XM antenna to pick up SXM Weather and Radio, which I'm assuming is why you bought the 52. As for the GPS antenna, if I were you I would just use a small puck antenna on it so it has it's own antenna.

2. The GDU 460 will also need a puck antenna. This should just fine. Also, the G5 most likely will not need an external antenna. The only time I've seen an external antenna on a G5 was where it was placed directly under the overhang of the panel and it was being blocked out when doing aerobatics or hard banks... the G5 was delayed in response, so Garmin recommended an external antenna and it fixed the problem. I've had G5s on at least 5 planes and have not had that issue with any of them but it's possible.

3. No. I don't think the GDL 52R can be used for backup attitude info to GDU or G5. It can provide attitude to Garmin Pilot and Foreflight - My understanding is that the GDL series only provide traffic and weather data to the G3X system and not attitude/GPS data (check with Garmin but I'm pretty sure).

4. Not sure I understand this question -

Just a couple of comments:
- If you have not bought the GDL 52R yet, you may want to consider the 52 if you have a place to put it. This eliminates a GPS antenna also gives you a built-in backup battery for the GDL (just another option).

- Since you've invested so much in a Garmin system, I'm not sure why you would consider another option for ADSB-IN . Having a tail beacon in the mix just seems out of place. I believe you can use GDL 82 with your current transponder and have everything be Garmin. (just a thought in case you have not bought these components). The other option would be the GTX45R but then you will have a 2 ADSB sources... Anyway, just a thought on the Tail beacon if you don't own it already.

Hope I didn't confuse you - Remember, the advise is worth what you pay for it . Good luck with it.

 

[mburch]

1. Yes, the GDL 52R will use GPS data received from other connected devices.

2. The GDU 460 does not have an internal GPS antenna, so at minimum you will need an antenna for that display. The G5 has an internal patch antenna right under the logo at the top. As the previous poster said, this may work as-is if not shaded too much by the metal glareshield.

3. No, the GDL 52R will not provide GPS data to your other displays.

4. The ARINC 429 and RS-232 outputs from the GPS 175 contain mostly different data. The MapMX RS-232 connection contains flight plan and other data that is not available via ARINC 429, and the ARINC 429 output contains IFR GPS deviation signals that are not available via RS-232. Don't ask me why, this is just a quirk of how IFR navigators have always been.

 

[rpigeek]

Thanks for the feedback Matt and BCP.
1. On the Skybeacon, it's because it's already in the plane for ADS-B out. Otherwise, would have done something different.
2. Still debating the GDL 52 vs 52R. Just a big box to be sitting on the top of the panel in an RV7, but a little simpler. Maybe add a little shelf for the back wall for it. I do like that if you lost everything it'll just run on battery with AHARS, GPS, Traffic and Weather for a couple hours for iPad/phone. And I already have one, so one subscription between planes if you move it...
3. I hadn't caught from the installation manual that "internal VFR GPS receiver" meant you still needed an external GPS antenna. Seems obvious now, but didn't initially.
4. For my other plane, Garmin did confirm as well that the GDU 450 can supply GPS to the GDL 52, but the GDL cannot send GPS data to the GDU. In that case I'd forego the GPS antenna if I go with the GDL 52R.
5. I'm still a little fuzzy on what data goes over RS232 x2, A429 x2, HSDB and Canbus connections and why between GAD 29 and GPS 175. I understand it's probably due to some legacy TSO approvals and common mode failures, but it's still fuzzy particularly as some of it uses marketing terms (i.e. Connext).

 

[mburch]

Still debating the GDL 52 vs 52R. Just a big box to be sitting on the top of the panel in an RV7, but a little simpler. Maybe add a little shelf for the back wall for it. I do like that if you lost everything it'll just run on battery with AHARS, GPS, Traffic and Weather for a couple hours for iPad/phone.

I have a bit of experience in this area, and I would trust a G5 over the "attitude feature" of something like a GDL or GTX every day.