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-   -   uAvionix MUX, GTX327 and AFS EFIS connections (http://www.vansairforce.com/community/showthread.php?t=179849)

flysrv10 02-24-2020 05:54 PM

uAvionix MUX, GTX327 and AFS EFIS connections
 
I have the above equipment connected and get traffic and weather on my EFIS via WiFi. However, I am looking for someone that has the same setup and is getting ADSB In through RS232. A wiring diagram and the port settings will help me with my setup. Thank you.

Veetail88 02-24-2020 10:11 PM

Quote:

Originally Posted by flysrv10 (Post 1410152)
I have the above equipment connected and get traffic and weather on my EFIS via WiFi. However, I am looking for someone that has the same setup and is getting ADSB In through RS232. A wiring diagram and the port settings will help me with my setup. Thank you.

I have an AFS 4500, gtx327 and uavionix EchoUAT with SkyFyx GPS antenna. Hot and ground from the gps and echo, signal wire from gps antenna to the echo and one signal wire to an open serial port on the EFIS. No MUX harness or anything else. Configured to sense the squeak and alt from the transponder. Had a couple weaning issues, but it is fully functioning now.

flysrv10 02-25-2020 03:20 AM

Quote:

Originally Posted by Veetail88 (Post 1410203)
I have an AFS 4500, gtx327 and uavionix EchoUAT with SkyFyx GPS antenna. Hot and ground from the gps and echo, signal wire from gps antenna to the echo and one signal wire to an open serial port on the EFIS. No MUX harness or anything else. Configured to sense the squeak and alt from the transponder. Had a couple weaning issues, but it is fully functioning now.

So why am I being told I need a MUX, I wonder. Same setup as yours!

Can you share your EFIS port setting and a pic of the Echo configuration page on your iPhone? Thanks.

Veetail88 02-25-2020 07:16 AM

Iíll send you my settings later on today. Left my phone in the car. There really is only one setting thatís a bit out of the ordinary to make the sensing work better. I think hard wiring might be better as the Echo gets the signals from the transponder instantly, but so far, and Iíve only had it installed for a week, the sensing works fine and monitoring the unit with the phone app shows itís getting squawk code and altitude while Iím still on the ground. The idea is that the transponder doesnít transmit until itís been interrogated from ground radar, so depending on the airport youíre taking off from that wonít happen until youíre airborne. And by the way, the sensing is built into the unit. Nothing extra to buy.

Kent Ashton 02-25-2020 07:18 AM

Not sure what your wiring is but that Uavionics "MUX" business is not very clear in the manual. If your Garmin 327 receives encoder information through a 10-wire gray code connection, it cannot send the transponder information to an EchoUAT. If you are using a one-wire serial connection from the encoder, it can.

This is as-of last fall when I installed an EchoUAT.

Veetail88 02-25-2020 07:29 AM

Quote:

Originally Posted by Kent Ashton (Post 1410247)
Not sure what your wiring is but that Uavionics "MUX" business is not very clear in the manual. If your Garmin 327 receives encoder information through a 10-wire gray code connection, it cannot send the transponder information to an EchoUAT. If you are using a one-wire serial connection from the encoder, it can.

This is as-of last fall when I installed an EchoUAT.




That is still the case.

flysrv10 02-25-2020 07:47 AM

Quote:

Originally Posted by Kent Ashton (Post 1410247)
Not sure what your wiring is but that Uavionics "MUX" business is not very clear in the manual. If your Garmin 327 receives encoder information through a 10-wire gray code connection, it cannot send the transponder information to an EchoUAT. If you are using a one-wire serial connection from the encoder, it can.

This is as-of last fall when I installed an EchoUAT.

So I don't have a 10 wire connection to any device. I am digging hard into the installation and you are right, the MUX is not well documented. Thanks.

lr172 02-25-2020 08:32 AM

Quote:

Originally Posted by flysrv10 (Post 1410217)
So why am I being told I need a MUX, I wonder. Same setup as yours!

Can you share your EFIS port setting and a pic of the Echo configuration page on your iPhone? Thanks.

The mux will send serial data to the uavionix, so that it always has updated altitude data. Otherwise, it only gets that data by sniffing when the transponder replies to an interrogation. In some areas, it will not be interrogated that often and therefore doesn't reply that often. It makes for a more accurate setup.

flysrv10 02-25-2020 09:55 AM

Quote:

Originally Posted by Veetail88 (Post 1410244)
Iíll send you my settings later on today. Left my phone in the car. There really is only one setting thatís a bit out of the ordinary to make the sensing work better. I think hard wiring might be better as the Echo gets the signals from the transponder instantly, but so far, and Iíve only had it installed for a week, the sensing works fine and monitoring the unit with the phone app shows itís getting squawk code and altitude while Iím still on the ground. The idea is that the transponder doesnít transmit until itís been interrogated from ground radar, so depending on the airport youíre taking off from that wonít happen until youíre airborne. And by the way, the sensing is built into the unit. Nothing extra to buy.

I think you solved my problem. No need to send any info right now. I junked the MUX and it looks like I have it working. Will do a flight test tomorrow and let you know.

akschu 02-25-2020 01:11 PM

From what I understand the echoUAT only has two serial ports, and one of them is used up getting GPS data from a WAAS gps or the SKYFYX.

This leaves only one RX input on COM1. This normally wouldn't be a problem, but as I understand it (confirm with uAvionix), the GTX327 doesn't spit out the altitude information in it's serial interface, only the squawk code. This means that you also need data from the encoder, which would require a 3rd serial interface.

This is where the mux comes in. It gets data from the GTX327 *AND* the encoder, mux's it together (not electrically combine, but makes a single data stream that has information from both boxes), so that it can be sent to the echoUAT on COM1.

I suppose you could just set the thing to listen for your transponder being interrogated, but I think that's a poor solution. Here is why:

1. Why mess with signal thresholds when you can just have the transponder and encoder tell you what is going on over a serial interface?

2. Anonymous mode works better because the echoUAT doesn't have to listen for an interrogation (to confirm 1200) before going into anonymous mode. The second stuff is powered on it knows you are squawking 1200 even if in a hangar and immediately goes into anonymous mode.

3. Many of the issues people report with the skybeacon and the tuning it takes to resolve them simply go away. Nothing is ever out of sync.

Why take the path of least resistance? Get the mux, put one pin to ground, one to the GTX, one to the echoUAT, and one to the encoder and be done with it.

schu


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