Trig TT31 GPS input

[RV8iator]

I'm trying to get my Garmin 496 to successfully communicate with a Trig 31 transponder so the ADS-b output will work.

I know before the fact that this is not a "certified" GPS and will not be legal for the 2020 mandate so that's not what this thread is about.

I need WAAS input to get ADS-b out. The 496 is putting out NMEA 183 at FAST setting, 9600 baud and the Trig is set to receive that. I have tried 4800, Aviation IN, Normal speed and the lat/long always works on the Trig.
What happens is I'm sporadically getting a warning on the Trig for invalid ADS position. It looks like the culprit is the altitude portion because my signal sometimes displays the wrong altitude on the traffic display.

Does anybody have a 3/496 or other garmin portable correctly talking to a Trig unit?

and

What could be different about a NMEA string on a portable and a panel mount that would be different that the Trig wouldn't recognize it? I thought NMEA was NMEA.

[Mel]

My 495 and Trigg communicate nicely. Never had a problem.
I'm on my way out the door now. I'll check out my settings when I get back. Maybe a couple of hours.

[strahler13]

My Garmin 510 and Trigg work very well too. Unfortunately, I had a friend install and don't know the details. I think it was easy and straight forward.

[Walt]

Is the altitude readout on the transponder correct?

[RV8iator]

Originally Posted by Walt

Is the altitude readout on the transponder correct?

The altitude readout on the transponder and what ATC sees is correct. It's just the ADS altitude that's not accurate.

I'm wondering if I need to actually put a ground wire in pin A on the secondary plug into the Trig. I thought that ground was ground so I only put a ground wire to pin 1 since they were adjacent to each other.

I'll try that and report back.

Meanwhile, would someone with a working pair send the settings of each unit so I can compare them to mine.

Thanks

[Walt]

The GPS input only provides postition reporting, not altitude.

I have installed a TT31/496 with no problems.

From the Trig manual:
"If the transponder has been configured for ADS-B operation, but a suitable position fix is not available, a warning message is displayed to indicate that ADS-B capability has been lost."

[RV8iator]

Originally Posted by Walt

The GPS input only provides postition reporting, not altitude.

I have installed a TT31/496 with no problems.

From the Trig manual:
"If the transponder has been configured for ADS-B operation, but a suitable position fix is not available, a warning message is displayed to indicate that ADS-B capability has been lost."

I get a good ADS position with lat/lon indicated on the Trig, even when I get the No ADS position warning. That's what has me puzzled. I get the error and press the function key to display ADS position and it's there and correct.

The altitude readout on the front of the Trig never waivers.

Are you using 4800 or 9600 baud?

[Walt]

TIS In/NMEA & VHF out is at 9600

[strahler13]

Jerry, here is info from Trigg:



The fact the TT31 is actually displaying longitude/latitude data means that he has the configuration setup correctly, for example:

- TT31 GPS input set to NMEA 0183

- TT31 baud set to 9600

- 495 set to TIS in/NMEA & VHF out



The warning message that keeps appearing means that the TT31 hasn?t received valid GPS information for about 2 seconds. The warning message is only cleared from the display by pressing a button on the TT31, even if the TT31 is now receiving valid GPS information, this sounds like the scenario RV8iator is experiencing. Some glitch in the GPS data causes the message to appear but then the GPS regains position and the TT31 is happy, although the message is still physically displayed until cleared by the operator.

The grounds at Pin 1 and Pin A are the same ground so swapping these should not make a difference unless there was a bad connection on one. The problem seems to be that the GPS data is getting occasionally lost which might be a loose connection or wire, the 495 losing satellites/position or something deeper which will be hard to track down without further information. If he still has a problem he should contact support@trig-avionics.com and we will be happy to help him further.

[Brantel]

NMEA is not NMEA since manufacturers sometimes add proprietary sentences to the data stream.

Garmin does this sometimes.

On my old 296 it had an option to enable or disable the extra Garmin proprietary stuff. I watched the data stream with that stuff turned on and turned off.

If it was on, the critical NMEA data would not update as fast as it would when that stuff was turned off.

If Trig needs an update at least every 2 seconds, make sure you have the NMEA stream as optimized as possible or you may see occasional errors.

NERD ALERT:

Here is some additional data about what happens when you select FAST vs NORMAL....

Originally Posted by rvator51

Hi Brian,

I already did this.

In the "Fast" mode, the Garmin outputs the following sentences:
GPRMC
GPRMB
GPRMH
as well as a series of proprietary garmin sentences then repeats.

In the 'Normal" mode, the Garmin outputs the following sentences:
GPRMC
GPRMB
GPGGA
GPGLL
GPBOD
GPBWC
GPVTG
GPXTE
GPRMH
GPAPB
then the proprietary garmin sentences and repeats.

The Dynon AP needs the following sentences to work with a GPS:
GPRMB
GPRMC
GPGGA
GPBOD or GPAPB

See http://wiki.dynonavionics.com/GPS_Se...ation_Settings

So the fast mode needs a couple more sentences before the Dynon AP can use it.

NERD ALERT!!
Heres the fast mode data stream:

$GPRMC,,V,,,,,,,281108,11.9,E,N*03
$GPRMB,V,,,,KFFZ,3327.6450,N,11143.7029,W,,,,V,N*3 4
$PGRMZ,,f,1*29
$PGRMH,V,,,,,,,*16
$PMRRC041KDVT<>
$PMRRC0512ND5:
$PMRRC0517KT6<
$PMRRC0511IP60
$PMRRC0510F@4<
$PMRRC0510H846
$PMRRC0519HL63

Heres the normal mode data stream"
$GPRMC,,V,,,,,,,281108,11.9,E,N*03
$GPRMB,V,,,,KFFZ,3327.6450,N,11143.7029,W,,,,V,N*3 4
$GPGGA,,,,,,0,00,,,M,,M,,*66
$GPGLL,,,,,,V,N*64
$GPBOD,,T,,M,KFFZ,*56
$GPBWC,,3327.6450,N,11143.7029,W,,T,,M,,N,KFFZ,N*4 4
$GPVTG,,T,,M,,N,,K,N*2C
$GPXTE,V,V,,,N,N*5E
$PGRMH,V,,,,,,,*16
$GPAPB,V,V,,,N,V,V,,,KFFZ,,,,,N*79
$PMRRC041KDVT<>
$PMRRC0512ND5:
$PMRRC0517KT6<
$PMRRC0511IP60
$PMRRC0510F@4<
$PMRRC0510H846
$PMRRC0519HL63
$PMRRC043KFFZ<8
$PMRRC0532F:4:
$PMRRC0534HL60
$PMRRC0530LH5<
$PMRRC0530GL5;
$PMRRC053<JV74
$PMRRC0531I<4>