B

Bushcaddy

Well Known Member
Prior to installing the GDL 39 I was receiving traffic on my 796 thru my GTX 330, which has the ES upgrade. I recently installed the GDL 39, hard wiring it to power. It connects thru Bluetooth to my 796. Flew today for the first time w/the new system. I get the ADS-B traffic fine but am not getting TIS traffic. I did not change anything on the GTX 330. Do I need to revise some settings info? or look elsewhere for the problem? Thanks...
 
From the manual:

4.3 TRAFFIC
TRAFFIC SOURCE
The aera 795/796 is compatible with two different traffic sources; TIS-A traffic via
a Garmin Mode S Transponder (GTX 330), or ADS-B/TIS-B traffic via a GDL 39. When
the aera 795/796 is configured with both a Mode S transponder capable of receiving
TIS-A traffic and a GDL 39 capable of receiving ADS-B/TIS-B traffic the aera 795/796
will automatically switch between traffic sources. The following conditions describe
the traffic display logic.
• If the GTX is not receiving TIS-A traffic data, GDL 39 ADS-B traffic will be displayed.
• If the GDL 39 is receiving both air-to-air ADS-B traffic data and ground uplink
TIS-B traffic, then the GDL 39 ADS-B traffic will be displayed.
• If the GTX is receiving TIS-A traffic, and the GDL 39 is not receiving ground uplink
TIS-B traffic, then GTX TIS-A traffic will be displayed.
If more than one traffic source is configured, the current traffic source is annunciated
in the upper left corner of the Traffic Page.

If your GDL39 is getting the ground station based TIS-B traffic and air to air traffic, it will win over the TIS-A traffic. Most will agree that TIS-B is superior to TIS-A.....
 
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Brian, thanks for the info...wish I understoood all this better. What I was not receiving this morning was TIS-B traffic...so it sounds like the GTX 330 is not the issue?? The flight was in the Boston area so I am assuming that ADS-B coverage was not an issue....or could it be that there was simply no TIS-B traffic??? and that's why there was an X through that box indicating none?? The GDL 39 does connect instantly to my 796 so I'm not sure what is going on.
 
If it was TIS-B (ADS-B Ground Station) traffic you were not receiving but you were within range of a ground station, I would question where or not your 330ES has been properly configured and that it has been fed a position source as required to fill out the ES data set.

Did you recently upgrade the unit to ES?

Do you have it hooked up to a GPS and if so, what GPS and how is it connected?

Did you configure the xponder's settings as required for the ES to work properly?
 
Great thread!

I fly in and around the NYC class B and never see TIS-B. saw it once down around Philly, but busy places don't mean anyone is out there with ADSb OUT.

I just sent out my 330 for the ES upgrade and my dealer told me exactly what Brian said, he just needs to config a couple things once the box comes back to garmin then I am in business sending OUT the OUT signals.

I will not have any GPS feed into the OUT though...but I have a few years to close that requirement out.

I just want to get more traffic displayed as much of the time as possible!
 
Not having GPS hooked into your ES transponder will render it useless for the that purpose..
 
The GTX330 is connected thru a serial port to my 796. I assume this is the only GPS connection required?

Prior to getting the GDL 39 I was receiving traffic on my 796 thru the GTX 330.

I had the ES upgrade done thru my local avionics shop/garmin. I was told it was properly configured when I got it back.
 
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Depends :) You will get TIS-B only if you "wake up" the ground based transceiver (GBT). You need ADS-B OUT for that. 330ES can serve that purpose ONLY if it's sending out your current position, which it obtains from a GPS. It depends how your 796 is wired into the 330.. if it's only one direction (from 330 to 796) then this won't work.

Note that 796 being position source for the 330 is not 2020-compliant...you should be able to get away with it, though, until they start ignoring that signal... who knows when that'll be.
 
I believe the GPS is wired both ways, that was part of the discussion I had w/the avionics shop prior to getting the ES upgrade. I just sent the shop an email to confirm this and to ask what the Xpdr settings should be so I can double check it.

I did not know that my current configuration...GDL 39/GTX 330 ES/Aera 796, would not be compliant in 2020 though?????
 
Traffic alert - me

I have a GDL-39 bluetoothed to my 796. My transponder is GTX327 (no TIS).
I have never seen the TIS-B uplink on the 796 show anything but an X,
yet yesterday between Santa Barbara and San Luis Obispo, I recieved
a traffic alert. -01 (100 ft below) and on my immediate 6 :eek: After
a quick right turn, it disappeared. After turning back on course, it reappeared
for a few seconds. I know this was a shadow. I had to be recieving
TIS-B thru the GDL-39 as I have before in the LA basin. But my TIS-B
flag on the 796 (and my iPad w/garmin pilot) always have an X in the box.
What gives?
 
Bushcaddy said:
I believe the GPS is wired both ways, that was part of the discussion I had w/the avionics shop prior to getting the ES upgrade. I just sent the shop an email to confirm this and to ask what the Xpdr settings should be so I can double check it.

I did not know that my current configuration...GDL 39/GTX 330 ES/Aera 796, would not be compliant in 2020 though?????
Click to expand...

No sir it won't. The 796 will most likely never be certified as meeting the 2020 position source requirements.

As far as I know, the 330ES requires at least Aviation format to get a position source from a GPS and the preferred protocol is Garmin's ADS-B format.
The 796 can only provide NMEA out and that protocol does not have enough information in it to provide the 330ES what it needs to fill out the ES data set.

I am making some assumptions here because I don't have a 330ES installation manual. I may be wrong but I am betting I am close to the root of the issue....
 
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True, none of the Garmin transponders will accept the NMEA GPS data which is provided by portable GPS products. So, for example, you would not be able to connect a GPSMAP 696/796 to a GTX330ES as the position source.
 
Bushcaddy said:
I believe the GPS is wired both ways, that was part of the discussion I had w/the avionics shop prior to getting the ES upgrade. I just sent the shop an email to confirm this and to ask what the Xpdr settings should be so I can double check it.

I did not know that my current configuration...GDL 39/GTX 330 ES/Aera 796, would not be compliant in 2020 though?????
Click to expand...

Hello Don,

You have a great setup for receiving and displaying ADS-B traffic and weather, but these posters are correct that the NMEA output from the Aera 796 cannot be used to supply position and other data to the GTX 330 ES.

We suspect that the serial connection between your GTX 330 ES and the Aera 796 is one direction only and transmits TIS-A traffic data from your GTX 330 ES to the Aera 796.

Thanks,
Steve
 
Steve thanks for the follow up. I guess my question is what was the advantage of getting the ES upgrade to my GTX 330 if it couldn't take a position fix from my gps? I was under the impression (from my avionics shop) that the 3 components (GTX 330, GDL 39 and 796), working together, would give me ADS-B in and out. It appears that the only traffic I'll be getting is what I was already getting from my 330 before spending the $1200 on the upgrade. Am I incorrect? What am I missing? Thanks...
 
Your not getting much if you do not have the proper position source available for your GTX330ES other than you will be ready for 2020 when you install such a source.

It is unfortunate that your avionics shop misinformed you. I suspect this is fairly common these days since this ADS-B stuff is so new.

Hopefully soon there will be lower cost options for a certified position source available. When there are, as long as Garmin supports them, you will be ready to go....until then your option is to install a GPS (or a G3X system) that meets the needs of the GTX330ES.
 
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Chino Tom said:
I have a GDL-39 bluetoothed to my 796. My transponder is GTX327 (no TIS).
I have never seen the TIS-B uplink on the 796 show anything but an X,
yet yesterday between Santa Barbara and San Luis Obispo, I recieved
a traffic alert. -01 (100 ft below) and on my immediate 6 :eek: After
a quick right turn, it disappeared. After turning back on course, it reappeared
for a few seconds. I know this was a shadow. I had to be recieving
TIS-B thru the GDL-39 as I have before in the LA basin. But my TIS-B
flag on the 796 (and my iPad w/garmin pilot) always have an X in the box.
What gives?
Click to expand...

Tom,

Are you saying you have never not seen the X on the TIS-B box? Even when you were actually receiving TIS-B? I have piggy backed several times and the X goes away during that time.
 
Interesting thread

Trying to understand how this is all supposed to work as I have a similar (but not exactly the same) situation as the poster. I have 796, GDL-39 and GTX-327 and all are hard wired together. The TIS-B is always X'd out and I have not yet seen any targets displayed on the 796 even when I flew to the Dallas area last weekend. I have the GDL-39 diagnostic app on my iPad and at the same time I had nothing on the 796 the app showed good signals from 3 ground stations and that it was tracking 30 targets.
If the iPad app was tracking targets from the GDL39 should there have been something on the 796? Range rings on the 796 were 2M and 6M and the filter settings were set on Normal so I assumed the targets were outside the range setting.
I was getting ADSB weather such as METARS etc.
What causes the TIS-B to become active:confused:
 
uk_figs said:
Trying to understand how this is all supposed to work as I have a similar (but not exactly the same) situation as the poster. I have 796, GDL-39 and GTX-327 and all are hard wired together. The TIS-B is always X'd out and I have not yet seen any targets displayed on the 796 even when I flew to the Dallas area last weekend. I have the GDL-39 diagnostic app on my iPad and at the same time I had nothing on the 796 the app showed good signals from 3 ground stations and that it was tracking 30 targets.
If the iPad app was tracking targets from the GDL39 should there have been something on the 796? Range rings on the 796 were 2M and 6M and the filter settings were set on Normal so I assumed the targets were outside the range setting.
I was getting ADSB weather such as METARS etc.
What causes the TIS-B to become active:confused:
Click to expand...

Yes, most likely the filter settings were different on the 796 vs the Ipad app. Most likely what you were seeing on the Ipad were air to air targets which does not require anything other than the GDL39 to receive.

To get TIS-B, something must wake up the ground stations and get them to send you the TIS-B traffic info.

To wake them up you need an ADS-B out device like an ES enabled mode S transponder or a UAT. Both of these will wake up the ground stations and get them to send you traffic info.

The other less desirable way is to piggy back on an aircraft near you that has ADS-B out. If you are close enough, you can steal the traffic info being provided for that aircraft.

The bottom line is that the GDL-39 is a receiver only and the GTX327 is not an ES enabled mode S transponder.

By 2020 if you want to fly anywhere a mode C transponder is required today, you will be required to be ADS-B out enabled. This means that you will either need to replace your GTX327 with a ES enabled mode S transponder or install a UAT. Both of which will require a certified position source capable of meeting the 2020 standards (the 796 won't do that).

I can tell you this...once you start receiving TIS-B traffic, you will be amazed at how much traffic there is out there.....
 
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For all with questions about ADS-B, Garmin has an entire mini site dedicated to the subject:

Click to go there...
 
By the look of things...I should have spent my cash on a GDL 88 w/Waas instead of wasting $800 on the GDL 39, which I will have to replace to be compliant and/or spend a fortune having a GPS w/the required capabilities installed in my already too tight panel (tandem airplane). At least the GDL 88 can be remotely mounted out of the way and would not require panel surgery, that will ultimately cost me more $$.

I really feel like the avionics shop did a very poor job explaining what I was getting and I asked the question more than once...but I have only my own ignorance to blame. I've learned more about the ADS-B requirements from this thread than any of the other BS published.

Thank You to VAF!!
 
I have never noticed the TIS box not having an X. I will look closer next time.

Also, the MAP screen on the 796 is very bright and makes identifying
the traffic symbols difficult. On the chart screen (sectional) the traffic
symbols are very easy to see because of the washed out appearance
of that screen.

I was going to upgrade my transponder this year to the 330ES and use
my 796 to supply GPS data to take full advantage of my GDL 39. With the
info in this thread, that won't be happening. I wonder if there are any other
solutions with a different make of Xponder (Trig)?
 
Folks there is no compliant way to use NMEA to drive an ES transponder. The data required to fill out the ES data set does not exist in the NMEA protocol.

Steer clear of any ES or UAT solution that claims to be able to use NMEA....
 
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In my 696 I have the option in the setup menu of using only the GDL-39 input or GDL-39 and TIS from the 330. TIS traffic where I'm located in the Portland area has never worked very well and still doesn't. I wouldn't want to rely on TIS traffic if it's the same in other coverage areas.

I just shipped my 330 back for the ADS-B upgrade last week and looking forward to having great traffic coverage soon. Fortunately I just happen to have a 430W in my airplane to provide a location to the 330. Tomorrow the 430W gets the latest 5.01 software upgrade so it will be fully compliant. Thanks to G3Xpert on his help with the 330 upgrade.

Now my RV-8 buddy Randy with the GDL will get the benefit by flying next to me. As quoted from the local Garmin rep, "he will be a parasite on my hockey puck"! By being within my 15 mile range (hockey puck) he'll enjoy traffic without upgrading to ADS-B out. So there you go guys, no need to upgrade to ADS-B out if your flying buddies do instead.
 
Brantel said:
If it was TIS-B (ADS-B Ground Station) traffic you were not receiving but you were within range of a ground station, I would question where or not your 330ES has been properly configured and that it has been fed a position source as required to fill out the ES data set.

Did you recently upgrade the unit to ES?

Do you have it hooked up to a GPS and if so, what GPS and how is it connected?

Did you configure the xponder's settings as required for the ES to work properly?
Click to expand...

What's the protocol used for the 330 to get GPS data? RS-232??? "iN"? :confused:
 
Not sure because I don't have a manual for the 330ES.

For the GTX23ES the protocol is Garmin's "ADS-B" protocol on the RS232 serial port #2.

It is my understanding that the GTX23ES and the GTX330ES are very similar but one is marketed for the certified world and one is only for experimental and light sport use. That being said, most likely they need the same info to work.
 
Thanks Brian.

I know my standard 330 setup is rs232 to and from the GDU375. I'll have to look for the manual for the ES and confirm.
 
Brantel said:
Not sure because I don't have a manual for the 330ES.

For the GTX23ES the protocol is Garmin's "ADS-B" protocol on the RS232 serial port #2.

It is my understanding that the GTX23ES and the GTX330ES are very similar but one is marketed for the certified world and one is only for experimental and light sport use. That being said, most likely they need the same info to work.
Click to expand...

I have a 330 install manual but it doesn't cover the 330ES, anybody have one of these I could look at???
 
SmilingJack said:
What's the protocol used for the 330 to get GPS data? RS-232??? "iN"? :confused:
Click to expand...

Hello John,

Both the GNS 4XX/5XX and the GTN 6XX/7XX have relatively new RS-232 output channel format selections for ADS-B.

Set the GNS or GTN RS-232 Output format to ADS-B and set the GTX 330 ES RS-232 channel Input format to REMOTE.

It is a transmit only connection from the GNS/GTN to the GTX. Very simple to wire and configure.

Let us know if you have additional questions.

Thanks,
Steve
 
GTX-23ES and GDU 375

Will my GTX-23ES and G3X GDU 375 play well with each other to allow me to receive TIS-B and all other data that having ADS-B in and out provides? I know that as it stands now, the GDU 375 doesn't provide a certified position source to be 2020 compliant, but it would be nice to get all of the benefits that ADS-B (in and out) offers now until I'm forced to provide a "certified" position source at some point in time.
 
For now yes. The G3X system can provide the 23ES with the data to wake up the ground stations.
 
Brantel said:
For now yes. The G3X system can provide the 23ES with the data to wake up the ground stations.
Click to expand...

Great, Thanks!! Hopfully there will be an "affordable" certified position source that will be available by the time the 2020 mandate is implemented.
 
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