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uAvionix MUX, GTX327 and AFS EFIS connections

flysrv10

Well Known Member
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 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.
 
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.
 
I?ll send you my settings later on today. Left my phone in the car. There really is only one setting that?s 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 I?ve only had it installed for a week, the sensing works fine and monitoring the unit with the phone app shows it?s getting squawk code and altitude while I?m still on the ground. The idea is that the transponder doesn?t transmit until it?s been interrogated from ground radar, so depending on the airport you?re taking off from that won?t happen until you?re airborne. And by the way, the sensing is built into the unit. Nothing extra to buy.
 
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.
 
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.
 
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.
 
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.
 
I?ll send you my settings later on today. Left my phone in the car. There really is only one setting that?s 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 I?ve only had it installed for a week, the sensing works fine and monitoring the unit with the phone app shows it?s getting squawk code and altitude while I?m still on the ground. The idea is that the transponder doesn?t transmit until it?s been interrogated from ground radar, so depending on the airport you?re taking off from that won?t happen until you?re 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.
 
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
 
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

Thank you for your input. I have done exactly what you say (I think) and having trouble getting ADSB In on my EFIS.

I am in discussion with uAvionix. Perhaps they can say where I have messed up.

In the meantime, removing the MUX has allowed me to have ADSB In on the EFIS without going to WiFI (spotty connections). I will test fly tomorrow to get an FAA report and see how things shake out.
 
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.

Thank you for your information. I removed the MUX and today's flight gave a me a clean ADSB Report. My ADSB In also works which was the reason to ask for help. Still waiting on uAvionix to verify if MUX is needed. I don't want it if I don't need it!
 
Thank you for your information. I removed the MUX and today's flight gave a me a clean ADSB Report. My ADSB In also works which was the reason to ask for help. Still waiting on uAvionix to verify if MUX is needed. I don't want it if I don't need it!

Need? No, you can configure the echo to listen for your transponder.

The biggest con is that anonymous mode is effectively useless, so if you care about privacy then you want the mux.

I guess a lot of people don?t care that their location is public knowledge, I?m not one of them.
 
Need? No, you can configure the echo to listen for your transponder.

The biggest con is that anonymous mode is effectively useless, so if you care about privacy then you want the mux.

I guess a lot of people don?t care that their location is public knowledge, I?m not one of them.

Thanks. Makes sense. I mostly fly cross country and I am in touch with Flight Following so 90% of the time, I am public.
 
Thank you for your information. I removed the MUX and today's flight gave a me a clean ADSB Report. My ADSB In also works which was the reason to ask for help. Still waiting on uAvionix to verify if MUX is needed. I don't want it if I don't need it!


Very pleased to be able to help.
 
UAvionix Echo and GTX-327

So i have a 327 that gets it's altitude data from a legacy Dynon D-100. Do I have to have the MUX cable they talk about or will the Echo pickup the altitude and squawk code automatically? Access to the back of my 327 is limited and it would certainly be a simpler installation if I didn't have to pick out serial wires from it.

Thanks
 
So i have a 327 that gets it's altitude data from a legacy Dynon D-100. Do I have to have the MUX cable they talk about or will the Echo pickup the altitude and squawk code automatically? Access to the back of my 327 is limited and it would certainly be a simpler installation if I didn't have to pick out serial wires from it.

Thanks

Call David Wagner at uAvionix. Works part time. He knows his stuff. If I had his contact when I needed it. This thread would not exist.
 
Where can I purchase this MUX cable that is being discussed. I been searching mux and haven?t found anything. Just completing the Uavionix Echo install to a Garmin 327, and an AF-4500s. ATC says they are seeing two transponder altitude read outs.
 
Thank you for your information. I removed the MUX and today's flight gave a me a clean ADSB Report. My ADSB In also works which was the reason to ask for help. Still waiting on uAvionix to verify if MUX is needed. I don't want it if I don't need it!

I spoke at length with Shane at uAvionix today and got the info I needed. The MUX is not required, but can help resolve some situations where you might get failed reports.

Specifically, if you fly a lot in rural areas, class G airspace, or places where you might not get much in the way of radar coverage, or other aircraft interrogating your transponder or ADS-B much, you could see coverage drop outs, or at the very least BARO issues because you're not sending out recent pressure alt from your system. This can also happen if you're down low level a lot.

Where I fly mostly this is never an issue, so I'm going with the EchoUAT and Sky-FX-EXT and no MUX connection to my GTX 327. The nice thing is, if I ever need to add it, I can do it.
 
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