Trig ADS-B position issue

[Loren Jones]

I live under a Bravo airspace so I knew from the start that I needed ADS-B Out capability in my GT-VX2. I opted for Trig radios due to their compact size. The TT22 is their certified Transponder and it can be coupled to the TN72 which is their certified WAAS GPS position source for the TT22. I also went with the TA50 compact antenna for the TN72.

From the start, I struggled getting position info to the transponder. Early on we weren't sure if the TN72 was even working since there are no LEDs or anything to indicate its status. Mike, Gyro Technic's electronics guru, hooked a laptop up to the DB9 connector from the GPS and we saw that it was streaming something so we at least knew it was alive.

I was suspect of the antenna so I ordered another TA50 just in case. No luck with that. Another issue was the little QMA connector which is a small slip-ring type connector. It was really tricky to get properly seated in the tight space at the back of my pod. After adding a right-angle adapter to make connecting easier I would occasionally see position info, but it was flakey at best. The technical gurus at Trig suggested I needed more of a ground plane. (A radio guru friend didn't think that made much sense, but we tried it.) It did seem to lock on better with sitting on a large sheet of metal, but that wasn't a practical solution for my little gyro.

Throughout this we noted that my Kanardia PFD, which also includes a GPS along with the AHRS, has never had an issue locking onto the GPS signals, and always does so quickly. Its antenna was just slightly larger than the Trig, but not by much (not much larger than a quarter, vs. the nickel size of the Trig.) The Trig experts suggested trying a different style antenna. The bigger certified one was over $300 and was a little big for me to mount anywhere on my gyro. I did some sleuthing and found a compact GPS antenna designed for automative applications that matched all the electrical specs of the TA50....on Amazon....for $10!

Today I installed the Amazon antenna in exactly the same position as the TA50, and it quickly locked onto the satellites and never wavered. I did a test flight and had ADS-B tracking throughout. Such a relief. This has been tormenting me for a month!

 

[okikuma]

I live under a Bravo airspace so I knew from the start that I needed ADS-B Out capability in my GT-VX2. I opted for Trig radios due to their compact size. The TT22 is their certified Transponder and it can be coupled to the TN72 which is their certified WAAS GPS position source for the TT22. I also went with the TA50 compact antenna for the TN72.

From the start, I struggled getting position info to the transponder. Early on we weren't sure if the TN72 was even working since there are no LEDs or anything to indicate its status. Mike, Gyro Technic's electronics guru, hooked a laptop up to the DB9 connector from the GPS and we saw that it was streaming something so we at least knew it was alive.

I was suspect of the antenna so I ordered another TA50 just in case. No luck with that. Another issue was the little QMA connector which is a small slip-ring type connector. It was really tricky to get properly seated in the tight space at the back of my pod. After adding a right-angle adapter to make connecting easier I would occasionally see position info, but it was flakey at best. The technical gurus at Trig suggested I needed more of a ground plane. (A radio guru friend didn't think that made much sense, but we tried it.) It did seem to lock on better with sitting on a large sheet of metal, but that wasn't a practical solution for my little gyro.

Throughout this we noted that my Kanardia PFD, which also includes a GPS along with the AHRS, has never had an issue locking onto the GPS signals, and always does so quickly. Its antenna was just slightly larger than the Trig, but not by much (not much larger than a quarter, vs. the nickel size of the Trig.) The Trig experts suggested trying a different style antenna. The bigger certified one was over $300 and was a little big for me to mount anywhere on my gyro. I did some sleuthing and found a compact GPS antenna designed for automative applications that matched all the electrical specs of the TA50....on Amazon....for $10!

Today I installed the Amazon antenna in exactly the same position as the TA50, and it quickly locked onto the satellites and never wavered. I did a test flight and had ADS-B tracking throughout. Such a relief. This has been tormenting me for a month!

Loren,

Include some photos of both antennas.

Wayne

 

[bryancobb]

I love it when WalMart comes through for us for 25 cents when an avionics shop can't, for $5 thousand. Congrats!

 

[Resasi]

Great job Lauren, glad to hear success on that front.

Still have to get my T22 hooked up, connected through the MGL screen, the antenna mounted, then sort out the ADSB-out issue

 

[Loren Jones]

Great job Lauren, glad to hear success on that front.

Still have to get my T22 hooked up, connected through the MGL screen, the antenna mounted, then sort out the ADSB-out issue

Well if you go with the TN72 as your GPS position source, I can tell you which antenna to buy!

 

[Loren Jones]

Loren,

Include some photos of both antennas.

Wayne

Attached are pics of both. Here's a link to the Amazon-sourced antenna:

Amazon.com

 

[okikuma]

Interesting comparison. Maybe there's either a short or open trace, or a cold solder joint in the Trig example. I performed an internet search to see exactly what's inside an average GPS antenna "box" and this is what I found.

A horizontal loop with (I'm guessing) signal amplifier circuitry all in one package.

Wayne

 

[Loren Jones]

Interesting comparison. Maybe there's either a short or open trace, or a cold solder joint in the Trig example. I performed an internet search to see exactly what's inside an average GPS antenna "box" and this is what I found.

A horizontal loop with (I'm guessing) signal amplifier circuitry all in one package.

Wayne

Very interesting. I had the same results with two different Trig antennas so I'm guess it just has very weak reception. They're noticeably smaller than my other antennas. I'll get a comparison photo next time I have both together.

 

[PeterFromLA]

By the way, the Trig transponder TT22 works perfectly with EchoUAT - you get a solid ADS-B Out and In with the bonus of WIFI connection to your favorite EFB app... and I believe, it is cheaper than the Trig bundle.

 

[Loren Jones]

By the way, the Trig transponder TT22 works perfectly with EchoUAT - you get a solid ADS-B Out and In with the bonus of WIFI connection to your favorite EFB app... and I believe, it is cheaper than the Trig bundle.

I've looked at that but it looks like I still would have needed the TN72 as for a WAAS GPS source, so it would have been an expensive replacement for the portable Sentry.

 

[PeterFromLA]

I've looked at that but it looks like I still would have needed the TN72 as for a WAAS GPS source, so it would have been an expensive replacement for the portable Sentry.

The EchoUAT+ SkyFix GPS bundle is around $1500 today. you do not need anything extra but your legacy transponder. If that is expensive, then I cannot argue my point... BUT the ability to have WIFI feed into my EFB is priceless... I retired my $700 Stratus 3, just don't need it anymore...

 

[Loren Jones]

The EchoUAT+ SkyFix GPS bundle is around $1500 today. you do not need anything extra but your legacy transponder. If that is expensive, then I cannot argue my point... BUT the ability to have WIFI feed into my EFB is priceless... I retired my $700 Stratus 3, just don't need it anymore...

Since this was a new install I was doing a new Mode S transponder that supported ADS-B from the start, so all I had to add was the $495 WAAS GPS position source. It would be nice to have the integrated IN capability, but I already had both a Stratus 2 and a Sentry, so there was no extra cost in that regard. I have one more button to push before starting up (and I COULD integrate it into the panel so that it powered up automatically, but I like to have it available as a portable backup when I'm flying my airplane, which has a permanently installed Stratus 2 integrated with the Stratus Transponder in it.)

 

[loftus]

Since this was a new install I was doing a new Mode S transponder that supported ADS-B from the start, so all I had to add was the $495 WAAS GPS position source. It would be nice to have the integrated IN capability, but I already had both a Stratus 2 and a Sentry, so there was no extra cost in that regard. I have one more button to push before starting up (and I COULD integrate it into the panel so that it powered up automatically, but I like to have it available as a portable backup when I'm flying my airplane, which has a permanently installed Stratus 2 integrated with the Stratus Transponder in it.)

Loren, do I understand that you have installed only ADS-B out?

 

[Loren Jones]

Loren, do I understand that you have installed only ADS-B out?

Yes, because that's the part that's actually tied to the aircraft. There are a number of relatively inexpensive ADSB-In solutions available, of which I already own three. I carry a little Stratus Sentry with me that feeds the In data to ForeFlight running on my phone, which sits in a charging holder in the center of my panel. Works very well.

 

[Tyger]

Today I installed the Amazon antenna in exactly the same position as the TA50, and it quickly locked onto the satellites and never wavered. I did a test flight and had ADS-B tracking throughout. Such a relief. This has been tormenting me for a month!

I also had an issue with my TA50 antenna. After a lot of fooling around with wires and connectors, trying to figure out where my (intermittent) problem lay; my conclusion was that I had somehow damaged the wire that's part of the antenna one of the times when I had disconnected it (trying to reroute things).
It would be receiving just fine on the ground, but once I took off, I would lose the signal. It was VERY frustrating. I finally solved the problem by getting a new TA50 and then being very careful connecting it up. The new one has always worked perfectly.
Again, my conclusion is that the TA50 QMA ring connector is quite hard to disconnect and the wiring to it quite easy to damage when attempting that. Use caution if you ever need to disconnect!

 

[Loren Jones]

I also had an issue with my TA50 antenna. After a lot of fooling around with wires and connectors, trying to figure out where my (intermittent) problem lay; my conclusion was that I had somehow damaged the wire that's part of the antenna one of the times when I had disconnected it (trying to reroute things).
It would be receiving just fine on the ground, but once I took off, I would lose the signal. It was VERY frustrating. I finally solved the problem by getting a new TA50 and then being very careful connecting it up. The new one has always worked perfectly.
Again, my conclusion is that the TA50 QMA ring connector is quite hard to disconnect and the wiring to it quite easy to damage when attempting that. Use caution if you ever need to disconnect!

I guess that's a possibility, but I even bought a second TA50 and had exactly the same problem. We did experiment with putting it on a larger flat piece of aluminum away from the gyro and it actually connect more reliably there. Not sure why that would make a difference. But it's interesting when a $10 unit works better than a $100 unit!

 

[Tyger]

Ya, mine was on a very tiny shelf. I don't think these antennae really have "ground plane" issues. Hand-held GPSes usually work fine in all sorts of positions, as long as they can "see" the sky.
That said, if I had known about your $10 antenna, I might well have tried that!