[sbalmos]

Powered up everything, and only two oddities I'm noticing in my whole stack. Thought I'd post anyway to see if I'd get a response before Oshkosh. I can talk to anyone at Team X or otherwise at the show next week if necessary.

1. My VPX Sport is the only box that my GDU 460 MFD cannot communicate with. The serial port is configured for Vertical Power, and (even more oddly) I have the green check mark next to the port, signifying a link. But back in the system info page, the VPX itself has model unknown, no info, etc, and I don't actually get the VPX status / control page in normal operation mode. The VPX Configuration program on my laptop also notes that the VPX is not receiving EFIS data. I'll obviously check wiring. But what's stumping me is the fact that I get a green data-link-OK check mark in the RS-232 port configuration page.

2. This one may be a ghost. But if my GDU 460 PFD's built-in GPS does not have a signal lock (I'm still doing all this testing in my garage with an open garage door), then the RS-232 uplink from my MFD to my GDL 39R ADSB box is lost. What's weird here is that in the system information page in configuration mode, the LRU line for the 39R visibly flaps between listing a GDL 39R and my GTX 23ES transponder. The separate status line for the GTX 23ES itself is fine.

Both the PFD and MFD are running 4.40, my GTN 650 is running 6.11 (throwing that in since the transponder is connected through the GTN), other firmware version numbers I'd have to get later tonight when I'm back home if necessary.

 

[Brantel]

1. Seems like a likely wiring issue. Make sure the TX of the VPX is connected to the RX of the G3X and vice versa.

2. On my system, the GDL39 3D must have a GPS lock for it to appear to be communicating. It can have its own or borrow it from the G3X system. No lock, no talk at least on mine...

 

[sbalmos]

1. Yeah, that was my only thought was a TX/RX wiring stupidity. That's what I'm checking later tonight.

2. Okay, ghost... I think. Just weird that the config page flaps between listing the 39R and my 23ES on that line.

 

[Brantel]

1. Yeah, that was my only thought was a TX/RX wiring stupidity. That's what I'm checking later tonight.

2. Okay, ghost... I think. Just weird that the config page flaps between listing the 39R and my 23ES on that line.

I really have never seen #2 happen so that may be something else...

 

[sbalmos]

1. Yeah, the RS-232 RX and Signal Ground pins were flipped at the VPX J1 connector in my master spreadsheet. Garbage In, Garbage Out. VPX is talking fine now.

2. So this is part ghost, part config question... The entry that was flapping between the GDL 39R and GTX 23ES in the System Info page was the Traffic entry. On a thought, I disabled the TIS-A Traffic Data function in my 23ES transponder's config page, and no more flapping - only showing the 39R as the applicable LRU under Traffic. Even started receiving air-to-air traffic in normal operation inside my garage (though no TIS-B or weather since a ground station can't reach inside my garage. ). So the overall question being, should I keep TIS-A Traffic Data disabled in the transponder?

 

[g3xpert]

So the overall question being, should I keep TIS-A Traffic Data disabled in the transponder?

I do because TIS-A will override TIS-B and I find TIS-B much better than TIS-A....

Hello Scott,

Actually, your G3X Touch displays will preferentially show TIS-B traffic over TIS-A, as described in section 7.3 of the pilot's guide:

When the G3X Touch system is configured with both a Mode S transponder capable of receiving TIS-A traffic and a GDL 39/39R
capable of receiving ADS-B/TIS-B traffic the G3X Touch 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 39/39R ADS-B traffic will be displayed.
• If the GDL 39/39R is receiving both air-to-air ADS-B traffic data and ground uplink TIS-B traffic, then the GDL 39/39R ADS-B traffic will be displayed.
• If the GTX is receiving TIS-A traffic, and the GDL 39/39R is not receiving ground uplink TIS-B traffic, then GTX TIS-A traffic will be displayed.

In other words, when TIS-A traffic data is available, it will be displayed only in cases where TIS-B service is not available. Both TIS-A and TIS-B traffic data ultimately comes from the same radar picture that the controller sees, so TIS-A can be a useful backup to TIS-B if for some reason you are not in ground station coverage, or the ground station has decided not to provide you with TIS-B service. Of course, the choice to enable or disable TIS-A data is entirely up to you.

- Matt

 

[Brantel]

Thanks for the correction Matt. I must be remembering how it used to be or remember wrong!

I deleted my post to prevent confusion...

 

[maus92]

I need to go back into my configuration and reenable TIS-A. I thought at some point the recommendation was to disable TIS-A if you were using a GDL-39R because receiving / using both TIS-A and TIS-B might lead to ghosting / false targets (I cannot remember...) Anyway, I encountered an Aztec "overflying" CGE a few weeks back presumably using the airport as a waypoint. He was flying at less than 2000' and not talking on CTAF. I had just crossed midfield at 2K' and descending to setup for the 45 when I saw him in my face, and NOT as an ADS-B air-to-air or a TIS-B target. This was the first time I ever heard the G3X system say "Sink Rate." Ahem.... After regaining my composure, I noticed that I was out of range of ground stations, but still had air-to-air. I should have still been in range of approach radar, so I'm assuming that if TIS-A had been enabled, I would have seen the Aztec on my traffic display (assuming he had a working transponder.)