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GDL82 install questions

USCANAM

Well Known Member
Hi All
I see it?s been 7 years since last I was on this great forum. Probably about the same time I met Doug at Oshkosh.

Still flying our -9, and am going to try an fly it more, therefore we are getting the plane ads-b compliment.
Just got back from Oshkosh with my 13 year old grandson, where we purchased the GDL82. His first cross country. Almost 2000 miles round trip. (Shouldn?t have been that far, but weather dictated that).

Like most things advertised, by reading some posts on the forum, I?m seeing that while installation is fairly straightforward, it?s not that simple as there is some computer work to be accomplished. Not my strongest talent.

The unit has not arrived yet but I did look at the manual on line.
Install will be no problem as I built my panel and I have the proper crimpers
I have a laptop and could probably figure out how to configure the unit once installed.
Right now the questions I have are
1. How do you connect the unit to the computer, and
2. Is this configuration step necessary?

Good to be back

Thanks
Jack
 
The installation wiring includes the addition of a USB connector to the GDL82, this is where you connect the laptop. You download the configuration software to the laptop and it autodetects the 82 when you power it up. Basically you tell it your N number and configure a couple of discretes (anonymous mode, squat switch, fault light etc.) based on your specific install. It will also tell you that the GPS is working properly. Pretty straight forward.
The USB wires are very small but my normal D sub pin crimper worked fine on them.
Figs
 
GDL 82

I have purchased a gdl82 and would like to know if mounting the gps antenna on the glare shield of a7 slider works out ok.
Thanks
 
The installation wiring includes the addition of a USB connector to the GDL82, this is where you connect the laptop. You download the configuration software to the laptop and it autodetects the 82 when you power it up. Basically you tell it your N number and configure a couple of discretes (anonymous mode, squat switch, fault light etc.) based on your specific install. It will also tell you that the GPS is working properly. Pretty straight forward.
The USB wires are very small but my normal D sub pin crimper worked fine on them.
Figs
Well explained! Thanks. Making a little more sense now.
Will start install shortly after unit arrives.

At one time I had 3 GPS antennas in the plane when it had the Blue Mountain EFIS. All three antennas were mounted on the overhead beam in the baggage compartment on small ledges with the antennas looking through the plexiglass.
All units seemed to work well with the antennas so close together. I removed the Blue Mountain years ago and replaced it with a GRT unit, so I intend to put the
82?s antenna on the BM antennas old mount which is still there.
Reading the Garmin install manual it says not to have the antennas close to each other, but since the GPS antenna does not transmit, I don?t see how it matters.
Appreciate any thoughts!
Jack
 
What Figs said, except you don't even need a laptop.

83hxc9.jpg
 
Reading the Garmin install manual it says not to have the antennas close to each other, but since the GPS antenna does not transmit, I don?t see how it matters.
Appreciate any thoughts!
Jack

Some of the antennas these days have amplifiers within them (they get dc power up the coax). They can radiate local oscillator signals. Worse, there are reports (here on VAF) that one failure mode of these amplifiers has them radiating strong signals, which can interfere with reception on near-by antennas. Other possibilities - unlikely here, I think - include the possibility that another nearby antenna on the same or nearly the same frequency can change the directional characteristics of both antennas - even though they both "just receive".
 
Just a warning but the depiction of the connector pins in the GDL-82 manual is backward when compared to the pinouts shown in other Garmin products such as the G5 and GMU-11. It is best to match the pin #'s using a magnifier to view the actual pin #'s on the HD connector.

Since the connector is a high-density DB15 the typical red-handled crimper does not work well as the pins are much smaller. You will need a Daniels crimper.

Once you get it powered up and USB connected then its just a matter of configuring a few options like N-number, stall speed, GPS input, etc.

After installation a flight test is necessary near a radar facility. A 30 minute flight at a constant altitude around the facility is all it takes to get a successful ADS-B report from the FAA.
 
Some of the antennas these days have amplifiers within them (they get dc power up the coax). They can radiate local oscillator signals. Worse, there are reports (here on VAF) that one failure mode of these amplifiers has them radiating strong signals, which can interfere with reception on near-by antennas. Other possibilities - unlikely here, I think - include the possibility that another nearby antenna on the same or nearly the same frequency can change the directional characteristics of both antennas - even though they both "just receive".

A nice article in the latest Kitplanes by Jim Weir talking about GPS antenna design. Basically, the signals received by these antennas are so weak, they have to be amplified at the antenna so the GPS receiver can detect them...measured in nanovolts...
 
Reading the Garmin install manual it says not to have the antennas close to each other, but since the GPS antenna does not transmit, I don?t see how it matters.
Appreciate any thoughts!
Jack

Hello Jack,

Thank you for choosing the GDL 82.

Certified GPS systems have many performance requirements, one of which is low angle satellite reception. The following statement in the antenna installation instructions explains why it is important to not have the GDL 82 GPS antenna too close to another antenna.

"To minimize the effects of shadowing at 5? elevation angles, the GPS antenna should be mounted no closer than 6 inches (edge to edge) from other antennas, including passive antennas such as another GPS antenna or XM antenna."

Let us know if you have additional questions.

Thanks,
Steve
 
Garmin quality decreasing?

I can't load a flight plan on my Garmin pilot anymore. Need to go another route.
 
Hello Jack,

Thank you for choosing the GDL 82.

Certified GPS systems have many performance requirements, one of which is low angle satellite reception. The following statement in the antenna installation instructions explains why it is important to not have the GDL 82 GPS antenna too close to another antenna.

"To minimize the effects of shadowing at 5? elevation angles, the GPS antenna should be mounted no closer than 6 inches (edge to edge) from other antennas, including passive antennas such as another GPS antenna or XM antenna."

Let us know if you have additional questions.

Thanks,
Steve
Thanks Steve for your explanation.
Will do as you?ve indicated.
Jack
 
Yes it does

I have purchased a gdl82 and would like to know if mounting the gps antenna on the glare shield of a7 slider works out ok.
Thanks
That is where I have the GPS antenna on my -7, works like a charm. Two points 1) the gps cable has to be a certain length (over 6 feet if I remember), if your install is behind the panel that is quite a loop to tie up somewhere, and 2) the antenna is white and cannot be painted so it does reflect in the windshield in hazy background conditions.
Figs
 
That is where I have the GPS antenna on my -7, works like a charm. Two points 1) the gps cable has to be a certain length (over 6 feet if I remember), if your install is behind the panel that is quite a loop to tie up somewhere, and 2) the antenna is white and cannot be painted so it does reflect in the windshield in hazy background conditions.
Figs

The antennas CAN be painted with some paints, I have my 650 antenna on the glareshield and painted black. It works fine.
 
Thanks Steve for your explanation.
Will do as you?ve indicated.
Jack

The Garmin party line is not supported in practice. I have three GPS antennas on my glareshield that work perfectly. I am moving my XM antenna there too. I maintain that this is why we do not have a certified plane, try it and if it works, it is fine...
 
The Garmin party line is not supported in practice. I have three GPS antennas on my glareshield that work perfectly. I am moving my XM antenna there too. I maintain that this is why we do not have a certified plane, try it and if it works, it is fine...

No, what your test proved is that it worked on that day. You need to test it under worst case conditions, when minimal satellites are in view, some of them low on the horizon.
 
What is the consensus on 1200 anonymous mode?
It only keeps you anonymous if you squawk 1200 for your entire flight. If, say, you depart from a Class C with a code and then switch to 1200-anonymous when clear, "the system" figures out who you are anyway and shows your entire flight. I "think" (not sure yet), that if you depart sqawking 1200 in the anonymous mode, then get a code when entering a Class C, "the system" doesn't back-stitch the first part of the flight. But that works the same when you're NOT in the anonymous mode. Yesterday I departed Knoxville Downtown squawking 1200 with the anonymous mode off, and flew to Asheville. Flight Aware only showed the last part of my flight when approach gave me a code. All that said, I'm not sure what the allure of remaining anonymous is (Unless someday they institute user fees.) I just don't use it.
 
What is the consensus on 1200 anonymous mode?

I have the GDL-82 and leave my anonymous switch ON all the time. If I'm ever given a squawk code then that overrides the anonymous mode. Why does big brother need to know who I am? The only other time it's off is when I want to request a PAPR report to see if everything is still working properly. I try to request one quarterly.

The GDL-82 is a great unit and it's coupled to my GTX-327.
 
Hello (Garmin) Steve,

I've installed a GDL 82 and am working out the bugs. I've flown the plane a couple of times and am trying to download the "assert" file to try and understand what the condition of the outgoing reporting might be. First question is, what does the "assert" file report?

Second issue. I've downloaded the file to my notebook pc and tried to extract the information. It appears to be a compressed file. It also seems to be password protected. Is there a Garmin created password I need to know? Or is this something related to this notebook pc?

Thanks
 
I don't know what an "assert file" is, but after I fly - if I want to check the performance of my GDL-82 - I request a ADS-B Performance Report. The FAA sends then via email within 30 minutes. There shouldn't be any red squares on your report if your unit is working properly.
 
GDL 82 install

Does the GDL 82 need to be oriented in any specific way or just wherever it fits best? On it?s side, upside down, etc does it matter?
 
Hello (Garmin) Steve,

I've installed a GDL 82 and am working out the bugs. I've flown the plane a couple of times and am trying to download the "assert" file to try and understand what the condition of the outgoing reporting might be. First question is, what does the "assert" file report?

Second issue. I've downloaded the file to my notebook pc and tried to extract the information. It appears to be a compressed file. It also seems to be password protected. Is there a Garmin created password I need to know? Or is this something related to this notebook pc?

Thanks

Hello Bryan,

The assert log has no value to a GDL 82 user.

We agree with John that the best way to find out how your system is performing is to request a PAPR report from the FAA. We do this anytime we make a change to one of our aircraft.

Thanks,
Steve
 
I installed my GDL82 behind the panel vertically on one of the ribs. The GA35 antenna is mounted under the cowl attached to the fire wall on an aluminum platform. I drilled a hole in the fire wall and ran the cable from the GA35 to my transponder.
Did my ADSB verification flight and passed on my second try. First try failed because I did not spend enough time in ?rule? airspace.
When you get your report from the FAA after doing your verification flight you will receive two attachments. One will tell you how,your equipment operated. The other will tell you if you passed or failed.
I really like my installation because nothing can be seen. Nothing on the glareshield and no additional antennas on the exterior
 
The GA35 antenna is mounted under the cowl attached to the fire wall on an aluminum platform.
What model RV, please? I have a friend with an RV-12 who is getting ready to install a GDL-82 and is looking for a good place for the GA-35 antenna. I guess you're probably aware that the installation manual specifies an ~18" dia. ground plane (6" from the perimeter of the antenna), but these smaller ground planes seem to work. I wish Garmin would elaborate on what size is really needed and why.
 
Antenna location

Don't know if relevant to the -12 but my -7 antenna is mounted on the dash with the 6ft of coax coiled up underneath. Just reviewed my latest FAA PR and once again zero errors.
Figs
 
What model RV, please? I have a friend with an RV-12 who is getting ready to install a GDL-82 and is looking for a good place for the GA-35 antenna. I guess you're probably aware that the installation manual specifies an ~18" dia. ground plane (6" from the perimeter of the antenna), but these smaller ground planes seem to work. I wish Garmin would elaborate on what size is really needed and why.
Mine is an RV9. The aluminum platform the GA35 is mounted on is just slightly wider than the antenna and barely as long.
 
Hello Bryan,

The assert log has no value to a GDL 82 user.

We agree with John that the best way to find out how your system is performing is to request a PAPR report from the FAA. We do this anytime we make a change to one of our aircraft.

Thanks,
Steve
Thanks for the info!
 
GDL82 install

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.**
 
USB port problems trying to use GDL8X Install Tool

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.
 
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).
 
GDL-82 input coax cable length critical

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
 
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