GTX 23ES with G3X
Also from OZ,
It is my understanding that an approved position source (Garmin GNS / GTN) is required to activate the ES component on the GTX23ES. No GNS / GTN no ADS-B.
Even with a GNS / GTN the GTX23ES still does not meet the required integrity requirements for CASA / Airservices Australia for IFR ADS-B compliance and has to have "
transmit only a value of zero for the NUCp or NIC"
With these values set to 0 (integrity) would I be correct in saying that it is pointless (for me) having ADS-B capability from the 23ES?
It appears at this stage the only ADS-B transponders that a fully approved (for IFR) are the Garmin (reasonable expensive solution) certified range and the TRIG units.
That being said:
- I dont know of any owners in Australia that use GTX23ES (I know two of the local Garmin re sellers have not sold any). Is anyone in OZ using the GTX23ES?
- Can I connect via RS232 (port 1) on the g3x to supply GPS position information to the TRIG transponder (fully certified) for ADS-B purposes (VFR) until I can afford to add an IFR GPS (GNS/GTN)
Hello Haydn,
You are certainly the expert on Australia here, but we wanted to comment on a couple of points.
1. The GTX 23ES is a certified 250W Mode S transponder with 1090ES. The latest V7.02 certified software released in early January upgrades the unit to have full TSO-C166b and ETSO-C166b "V2" ADS-B Out compliance. You certainly don't need to put another brand transponder in your G3X aircraft to have this capability. As shown on
this page, all this capability comes at an extremely competitive price.
2. A GNS/GTN certified position source is NOT required to enable 1090ES ADS-B Out transmissions. The single RS-232 bi-directional connection between the G3X GSU73 ADAHRS is used for transponder control and to provide the transponder with a continuous stream of data including pressure altitude and VFR WAAS GPS data.
3. The GTX 23ES, like all Garmin Mode S transponders, supports receiving ADS-B Out data from GNS/GTN certified position sources on a separate RS-232 port. When this data is provided, the GTX 23ES automatically recognizes that this data has higher positional accuracy/integrity and uses it to fill in the data fields in the 1090 Mhz extended squitter instead of the VFR GPS data being received from the G3X system.
4. If you reach up and turn off your GNS/GTN navigator, the GTX 23ES continues to send out the extended squitter, it just falls back to using the G3X provided VFR GPS data. As required by both the U.S. and Australia, the data fields in the extended squitter properly report the design assurance and integrity of the data thus assuring that ATC is not misled regarding the type of data being transmitted and it's suitability to be used for aircraft separation.
5. We are NOT sending National Marine Electronics Association "NMEA" GPS data to our transponder as it does not contain nearly enough information for the GTX 23ES to perform all the functions described above and Garmin Mode S transponders do not accept NMEA data. G3X integration with the GTX 23ES certified Mode S transponder provides the very best capability and performance that can be achieved whether you are using a VFR or an IFR installation.
6. Everything said above about GTX 23ES integration with G3X also applies to GTX 330ES integration with G3X. Whether you prefer a panel mount transponder or a remote mount one, both are excellent Mode S ADS-B Out solutions for G3X equipped experimental aircraft. When you combine this transponder ADS-B Out function with the
traffic and
weather ADS-B in capability offered by the dual frequency GDL 39 ADS-B receiver, your G3X aircraft is taking full advantage of all the benefits of ADS-B.
One final comment. While this system does not require any country specific "approvals" to operate in the U.S., you are in a better position than us to know if your country has different requirements.
Let us know if you have additional questions or if we can help further.
Thanks,
Steve
