ADS B

lwford

lwford

New member
Boys, I'm installing my third ADS B out in a Cherokee 235. This one is a Garmin GDL 82, the 978UAT using the same XPR and encoder. The one on the back page of TAP. I've done a Appareo Stratus and a BKing KT 74 coupled to Garmin 530. The GDL raises a question to me and this is the 1st I have seen this. The instructions call for a ground plane under the GPS antenna with 7" radius no problem on the Piper. Where would we put this on a Cruisemaster? I have an Apollo Antenna above the trim indicator on the crate and it has no ground plane yet worked great for 14 yrs. I like this UAT for the Anonymous mode. I always have some sort of issue loading the software on this crap. Anyhow has anybody addressed this issue on their ships? I would like some ideas. Lynn the crate :?:
 
Hi Lynn, coincidentally I have been researching the same issue recently. When speaking with various radio shops the default response is that all antenna need to have a metal ground plane. This does make sense when the antenna is radiating a signal in order to improve VSWR. However I question if the benefit is significant for a receiving antenna. Installing a ground plane in the top of a Cruisemaster certainly has some challenges - especially in my -3 because of a one-piece headliner beautifully installed prior to the fabric covering. So I conducted some research. I found a technical bulletin published by Comant/Cobham - a respected antenna manufacturer. It can be downloaded here:
https://www.cobham.com/media/5048/gpsantennainstallationguide.pdf
Of particular note in this document is the statement on page 2 which states "Comant GPS design does not require a ground plane". Now this is not to be confused with the logical requirement that the antenna frame does need to be "grounded" to the airframe which is sometimes also referred to as the ground plane. My intention is to install a high quality GPS antenna without the ground plane and evaluate the performance. Nonetheless I am continuing my research on this matter. Let us know what you decide to do... Rob
 
On my -3, there was a little ground plane for a com antenna not far behind the speaker. Rather than a new ground plane, we installed one od Comant’s combined comm/gps antennas. Expensive, but I did not trust the avionics shop to do fabric work installing the ground lane garmin wanted.

Thus far, I’ve never had a gps signal integrity check fail on the gtn650, so the tiny ground plane works well enough...
 
Larry, yes it was the CI-2580-200. It looks way too modern for the Bellanca, but has worked great. And, like I said, saved what I’m sure would have been an ugly fabric hack to add more mount points.
 
Last spring, we installed a GTN650/GTX345 in N9806B. My baggage compartment has a hole cut in the top for an old antenna mount. We mounted the new Garmin GPS antenna on top of the baggage compartment under the top fabric. It works well and there are no outside parts. The transponder antenna is on the bottom of the boot cowl. We passed the NPE report with no problems.
 
Ralph, that's valuable information and a creative solution. The Garmin combination is the same as what I have been looking at (and saving up for) - are you happy with the performance of these units? --Rob
 
I am happy, for the most part.
The GTN650 has been flawless. I can fly the LP approach at lots of airports making it as close to a sure thing that I will get to land in bad weather as you can ask for. It is connected to an old Century II autopilot so I can look out side and watch the towns and cities drift by without going off course. The buttons have been easier to learn than I thought they would be. Getting set up after the controller changes the plan has not been as hard as I was afraid it would be. I installed an Electronics International CGR-30P engine analyzer at the same time and it shares info with the GTN650 so I get fuel at destination/range information.
The GTX345 has had problems connecting to my Ipad. It took quite a bit of rework for the system to connect reliably. The key was to move the 345 to under the rear seat from under the baggage compartment and get it mounted in a very solid way. We also had a 345 go belly up in the first couple of hours. It was replaced under warranty. After the struggles getting it to work it has been fine, until last week when I had problems again with the connection. We will see if there is still a problem or not.
Getting traffic on the Ipad had been great, it is much easier to find potential problems if you know where to look. There is a voice warning for the traffic if you really are asleep at the switch. Having the weather on the Ipad and on the 650 screen has made it easy to make sure I am not heading into the bad stuff. I am a chicken so I tend to stay a long way away.
The CGR-30P does help to keep the engine happy. It is an exercise in frustration to get an O470 to run smoothly with all of the cylinders at the correct mixture at the same time. The CGR points out the really bad job the intake system is doing of getting air with the fuel to the cylinders. You can get air to all of the cylinders but fuel only goes to the front ones. By the time the rear ones have enough fuel the front ones are choking on excess fuel. By the time the front cylinders are making power the rear are way too lean. :?
It still seems really cool when we come out of the bottom of the overcast at the end of a trip and the runway appears like magic in front of us and we are on the glide slope to the TDZ.
 
Nice report and great looking panel Ralph. Thank you for the detailed feedback. I take it that you have the remote version of the GTX345 with the control working through the GTN650 display window? Are you also using the remote Garmin audio panel? Do you find the screen size of the 650 hinders its usefulness? Reason I ask is that in my -3 I have a little more panel space and I could accommodate the GTN750, but I don't want to spend the extra $ if the 650 works fine. Hard for me to make this determination without actually flying with this equipment.

Now regarding your comment "It is an exercise in frustration to get an O470 to run smoothly with all of the cylinders at the correct mixture at the same time." This of course is a real limitation with any carbureted engine and perhaps the main reason the O-470 only delivers 230hp where the IO-470 delivers 260hp - they are basically the same engine. Back when my -2 was operational I never cruised at much more than 65% power and never considered it a go-fast airplane (but extremely nice in every other way). When I started flying the -3 I noticed a big difference in performance - I really wish they had left the -3 sitting on a tail wheel, but kept all of the other improvements. Without the extra weight and drag up front it would be an even faster plane than it is.

Again, really appreciate all of your feedback... Rob Hey Lynn, sorry for the thread creep here!!!
 
The screen on the 650 is small. I do all of my map work on the iPad. If I had the 750 I would probably leave the iPad in the back seat with my luggage. The panel space is very limited and I didn’t want to hack it up. The 650 fit in the space I had perfectly. I have the remote 345. Entering a squawk code on the 650 is very convenient.

I ended up with a PS PMA4000 intercom. There was no room for a traditional audio panel and the PS 4000 has a small panel built in. So far it has been invisible, just like you would want it to be.

The IO 470 would be great, but I’m stuck with the carb. I run the O470 at 65% and get 142kts true at 12-13gph depending on how she feels that day. I can crank it up to 75% and get 151kts but it takes 15gph. In the winter it takes a little carb heat to keep it happy. 142kts(165mph) gets us around at a pretty good clip and we get front row parking when we go for pancakes. Most of the planes I have looked at that go faster cost a lot more even after the expensive panel (not so much on the -3). I not sure I can survive without the tailwheel anyway. 8)
 
Nice panel with the high tech gear. I'm an analog guy in a digital world. If I could of ever found an original instrument bezel, I would of made the crate like it just rolled out the door circa 1958. I like the Comant dual antenna, that seems the way to go for ADS-BS. Lynn the crate
 
I was just fine with my analog gages and flew the VOR/ILS approaches with no problems. 8) Then Chicago started sending me south to Peoria when I wanted to get to Minneapolis because they don’t want VOR only aircraft in their fancy airspace. Then the FAA said they were going to abandon the VORs I use to get home and it was clear that I needed a GPS to continue to play the game. So now I have more in the panel then the rest of the aircraft cost, and I can never sell it. I hope you guys don’t mind having me around, it doesn’t look like I’m leaving any time soon. :mrgreen:
 
Our Pal Mario has the Mooney Acclaim with G1000. He had ADS B XPR installed in the fall. Well the Garmin died this weekend. Pitt told him no XPR return and then I tested it with my radar box and it is dead. Garmin advertises like no other, maybe they need to spend on QC. I still think the Bendix King KT 76A is the best transponder made. Lynn the crate
 
Boys Garmin has posted a number of videos on You Tube for the GDL 82. Nothing yet showing real world install or loading real world software. It does help with the installation. Lynn the crate
 
Boys, the Garmin 82 install went without a hitch. I was worried about loading the software into the 82 with the Garmin app. That went very easy and was really neat to monitor how it picked up the GPS satellites. He flew the plane in the Mode C veil and it passed on the FAA website. If I were to install ADS-B in the crate, this would be the unit along with Comat dual antenna. I don't know if you can purchase the 82 with internal GPS without getting the Garmin antenna. It still would also cost you a grand to have it installed by avionics shop. I think anybody who knows a little about A&P work can install this unit although you need the tooling for the BNC/TNC crimp connectors. I also say that buying the made up wire harness from ACS is mandatory as it has the Usb-b connector. We will see what might be introduced at Sun & Fun in regard to ADS-B. Lynn the crate
 
I installed the Garmin GDL 82 in the crate (-2). I mounted the unit in the bottom well where the brake hoses are accessed. I put the unit on spruce hardwood standoffs and it is close to where the XPR antenna is mounted. To start with I went to do the Bi Annual S.A.T. and failed Mode C. Turns out the TCI encoder went bad. I had a Narco AT50A XPR but had bought my favorite XPR to put in the crate a King KT 76A. I removed the Narco and installed the King with a new TCI encoder using RG 400 replacing the RG 58. Now the SAT check passed. I then installed the 82 (this is my 6th ADS-B install). I decided to mount the Garmin antenna GA 35 included in the kit on the glare shield. I did a RV 8 and we mounted it's antenna under the canopy behind the rear seat. Worked great so why not on the glare shield and that solves the problem of fabric fuselage. I already have a GPS antenna on the cabin roof a Apollo UPS. I like that unit, of course Garmin bought that company and won't support what they have. I also have a Garmin 196 mounted on the panel and it's antenna is on the glare shield. Works great for many years.I also installed the options ADS-B fail light and Anonymous switch. I had my first problem as I could not program the unit and that turned out to be my computer. I had to reload the GDL Install tool app.and that fixed it. It's always the simple stuff that kicks your arse. I flew it and checked the FAA web and all green it passed. Now another item, I didn't like the glare from the white GPS ant reflecting in the windscreen. I covered it with black sock and that worked. I contacted Garmin about painting the antenna. It says do not paint on the antenna. They said you can't paint it, I said do you guys make it? The answer is no. It is made by AeroAntenna Tech. I contacted them and ended up getting a reply from a woman engineer at the company. She said sure you can paint it using a flat black light coat. That is exactly what I did and the performance stayed the same Yippi. So I'm becoming the go to guy for 82 installs. So far I have six more to go. I wanted to put this out on the forum about the computer and the paint. I also found out from Garmin support you do not need to use RG 400 on the XPR use the existing RG 58, they do require the RG 400 on the GPS Ant. I have left the existing RG 58 running from the XPR to the 82 and use the RG 400 from the 82 to the XPR antenna and the GPS Antenna. I also found out you could have a problem with the length of the USB A to B interface cable. I use a 10 ft cable on the 3 previous 82 installs no problem. Aircraft Spruce Avionics told me I needed a much shorter cable but it was my computer program that was the Gremlin after that the 10 ft job worked again. Putting these in is pretty easy but you need the proper tooling to install the dual crimp connectors. You could use the old built up ones but I don't think that would be a good idea. All said and done a basic 82 install is about 2350 bucks. I also recommend that you purchase the ACS prewired harness as it has the USB B wired in. I did an 82 on a light sport and had to wire the plug. You need the proper crimp tool for that so why not get it made up and no need for that expensive tool. Well now the crate is legal until the clowns change the rules again. It's their field and their game so we are just along for the ride. Lynn the crate
 
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