need suggestions with Garmin 795/GDL-39 3D

[Bill Boyd]

My tale of (maybe) woe:

Bought used GPS 795 last year. Works great. Just tied it into the autopilot with proper cabling (that was another thread) and the A/P is happy with what it sees, too.

Plan all along was to add GDL-39 functionality, and after looking at the 795's Synthetic vision 3-d terrain, there was no way I was going to have that in my face but depicting "no attitude information" - not sure my brain could ignore that display if I ever had another inadvertent foray into IMC. So I resolved to spend the extra bucks on the 3D model, in order to have a non-misleading 3D world shown on my GPS.

Another Ebay purchase later, I am the proud owner of a GDL-39 3D. Powered it up last night, linked it to the 795 via BlueTooth. Good external GPS flag, and air-to-air traffic display shown on the map page - there goes UAL880, altitude unknown. On the ground at home, there are no ADS-B towers within range, so I was not surprised by the lack of WX info. Allowing several minutes for "alignment," I was surprised not to see any attitude changes in the pictorial 3D terrain display when I moved the GDL-39 around to simulate pitch, roll and yaw movements. Display on the 795 flags "no attitude data." Several resets of both units do not change this.

Not sure if I need to be aircraft-in-motion in order to see these attitude changes on the display.

Before anyone asks, the units have software that is not the latest version (at least the GPS is vintage 2014 - not even sure how to check the GDL). I got as far as downloading the WebUpdater and Garmin Express onto the MacBook last night, then realized I don't have cables for either unit that connect USB to Garmin data port, nor do I see any Garmin cables with that connector combo in the literature for the GDL (haven't checked the 795 manual yet). So, I'm not even sure how to cable-up for a software update.

Full disclosure - 1. I am something of a Luddite, especially for a Mac-only guy. 2. This may be what I get for buying used gear. My panel will soon sport a GRT Mini-X, so I will have at least one source of accurate gyro data on display. Was just hoping for two.

Any clarification of what I might be doing wrong would be appreciated. I seem to have all the features of the GDL-39, but not the AHARS features of the -3D model that I held out for.

G3Xpert???

 

[Bill Boyd]

after browsing the internet

... the more I research this online, the more I am suspecting that the GDL-39 3D only displays MFD-like pitch/roll/yaw and moving synthetic vision on devices running the Garmin Pilot app and not on the GPS 795/796.

I certainly hope this is not the case, but it seems more likely as I delve into the product literature and users manuals. The only pictures and video I see of the 3D gyro functionality show it running on an iPad or iPhone. I like Apple hardware, but it's not anything close to the aviation portables for screen visibility in the RV cockpit.

Hopefully I'm mistaken about this, and the 795 will show 3D-real synthetic vision somewhere with the right set-up. But I suspect this is a case of seeing what I wanted to see in a technology instead of what was actually being proffered. If so, I plead (shiny object + dumb sucker) = (fool - money). Wouldn't be the first time

 

[greghughespdx]

Had similar problems until I did two things.

1. Update both devices to latest software, and
2. Connect via the hard wire cable rather than Bluetooth (the BT never worked reliably for me, might have been RF noise, not really sure)

After making those changes all traffic, attitude, weather, everything data working on the 795 with the GDL39 3D as the source.

 

[Bill Boyd]

Thanks, Greg

I will D/L the Garmin Pilot app onto the iPhone tonight and give it a go, make sure my GDL 39-3D is outputting AHRS data that way.

Maybe I should ask it this way. What does the -3D model do for the GPS-795/796 specifically that the plain vanilla GDL 39 won't do? Does it supply some pitch/roll/yaw movement to the Synth Vision or is that only seen on the tablet and phone devices running Garmin Pilot?

 

[greghughespdx]

GDL39 3D capabilities on 795/796:

TIS-B Traffic 30 targets
FIS-B weather
Connect via Bluetooth or cable
TargetTrend for traffic
Attitude data information from GDL39 3D
SVX

 

[g3xpert]

Hello Bill,

Here is a link to a posting explaining that we added support for using the attitude information from a GDL 39 3D in May 2014 with V4.40.

We recently added support for using the attitude sensors in the GTX 345 transponder.

Does your ebay GDL 39 3D say "GDL 39 w/AHRS" on the serial number tag? Just want to make sure you really have a 3D model.

You really should update aera 795 software to the latest software (V5.00) which will also update the GDL 39. If you go to the Software page, then click on Garmin Express it will give you the option to install either the Windows or Mac version. After that, connect a USB cable to the 795 and update.

This shouldn't be your problem, but since you must already have a bare wire mount to connect your aera 795 to the autopilot, we strongly recommend you use the second serial port to hardwire the GDL 39 to the aera 795.

Thanks,
Steve

 

[Bill Boyd]

You called it, Steve.

I have a gen-u-ine 3D model, and I was able to get it working with the iPhone last night after downloading a trial of Garmin Pilot - including the AHRS attitude functionality.

The issue is with my GPS 795, which has software v 4.3. I will remedy that as soon as I get a compatible USB cable to connect to my MacBook. (I assume BlueTooth connection cannot be used for this task). Looks to be a Type-A to Type mini-B cable.

I updated the GDL 39 to version 4.7 (if memory serves). Playing around with the three units last night (GPS, GDL and phone) convinced me that your recommendation of hard wiring the Garmin units together is well-founded. The BT connection is temperamental at best; no way I want to do all that rebooting and reconnecting in flight.

I trust the 5.0 upgrade for my 795 will fix the no-attitude issue. Thank you for providing the photo of the attitude display active on the 795/796 - that's the first time I can recall seeing the feature depicted on anything but a mobile device running G-Pilot. I was beginning to think I had made a big panel-planning blunder, but kudos to Garmin, I have not

Thanks again, Steve.

 

[Bill Boyd]

Garmin online experience

as seen through the eyes of a Mac-only, computer-timid older guy: they have the whole experience pretty plug-and-play and Mac-friendly now, except for the need to exit Chrome (doesn't support the plug-inis required) and default to Safari.

The frustrating part was not the firmware upgrade to 5.0 on the Aera 795, which went very fast and easy, but the purchase of a chart subscription. Why does it take Garmin so long to process a credit card when Amazon does it in nothing flat? I'm not sure how long I can leave my portable powered up and cabled to the laptop here at work w/o a charger, waiting for the email from FlyGarmin saying my purchase has been approved. This part of the experience I would rate sub-par. What if I was planning to leave for a X/C this morning and this was part of last-minute flight planning? That would not be nice.