GDL82 install questions - Page 4

juscash · #31 12-19-2018, 01:02 PM

My RV-6 GDL82 is mounted on a bracket attached to the bottom of the instrument sub panel.* The antenna is mounted on a bracket*attached to the motor mount alongside the GPS antenna.* Both antennas have a 7.5 inch aluminum ground plane.* I didn't read the install directions carefully enough so the*antenna lead is 4ft instead of the 6ft called out*in the directions.* This installation passed the conformity test on the first try.**

ultimate10201 · #32 01-09-2019, 04:42 PM

I installed a GDL82 in my RV7 and tried to follow the instructions to configure my unit using the install tool.

But it appears my computer and the GDL82 can't talk to one another. As per the instructions, I downloaded the tool from Garmin's site. Next, I plugged the USB cable into my laptop and then with the GDL82 not powered up, I connected the cable to the GDL82 adapter cable. I powered up the GDL82 and then opened the tool. Unfortunately, the start up box does not show that the GDL82 is present. My computer and the GDL82 are not communicating with one another.

I also followed the instructions with my Device Manager open so I could see the USB ports. When I plugged the USB cable into the GDL82 adapter (GDL82 not powered up), my computer immediately dings me and opens a new line on the Device Manager that says 'Unkown USB Device (Port Reset Failed)'. I didn't even open the install tool because the USB port is useless, apparently. I searched and followed much advice about repairing the USB drivers, uninstalling, restarting, etc. No luck.

It's pretty apparent this is a computer problem, specifically with the USB port. 5 year old Lenovo, Windows 10.

Anybody seen this problem? Fixes?

Plan to borrow a friends computer tomorrow to see if it will work.

Any help appreciated.

ArlingtonRV · #33 01-09-2019, 05:44 PM

I had a similar problem, except that I did get the "GDL-82 Present", I just couldn't connect from there. My problem turned out to be the USB cable I was connecting to my laptop. Garmin support told me to use a cable no longer than 4' and to use a "high quality cable".

I was using a 15' Amazon Basics cable and couldn't connect. I replaced that with a 6' cable (couldn't find a 3') and it connected right away (well, ok, right away after a few computer reboots).

dmeloche · #34 08-22-2020, 09:27 AM

I would like to pass on my experience installing the GDL-82 in my RV6 in the hope it will keep others from going through a long and expensive troubleshooting process like I did. I have a SL-70 transponder feeding the GDL-82. A bench check showed it had plenty of output power so I went ahead with the purchase and installation. I mounted the GDL-82 behind the panel just downstream from the back of the transponder. I thought this was a good idea, the short input coax cable length would minimize power loss. This turned out to be a bad assumption. After installing the system I went through the initialization steps. I kept getting fail messages from the SL-70 saying that there was an antenna failure. I discovered that I had wired the attenuation light incorrectly and thought maybe that had caused the problem. I contacted Garmin, told them what I did and they sent me another unit, thinking mine had been damaged. The new one did the same thing. SL-70 antenna fail messages, usually anywhere from immediately to 1 hour into the flight. The coax input cable was replaced after finding a cold solder joint, the output coax cable was replaced, just for good measure and the antenna was swapped out. The local avionics shop (Garmin dealer) called Garmin support numerous times looking for advice to no avail. Thankfully the avionics shop would not give up and kept going through the Garmin support staff until he found someone who was expert at the GDL-82. He surmised that the high power output from the SL-70 combined with the short input cable was causing the unit to have to attenuate the input signal eventually overheating the unit and causing it to shut down. He suggested an 8ft(!) input cable length. I'm not happy about having to snake around this much cable behind the panel but this has finally solved the problem. My thinking that a short (8") input cable would be helpful was wrong. Note that there is NO advice in the installation manual regarding minimum input cable length or the potential to overpower the GDL-82. SO watch your input cable length, especially if you have a powerful transponder. Thanks to Greg at Pippen & York at Gillespie Co airport TX for refusing to be stumped.

Doug M
RV6 900hrs