NMEA possibilities with Aera 760

[Ed Haywood]

I just pulled the trigger on an AV-30C on sale for my Decathlon rebuild, and have been reading about NMEA input to drive the HSI. I do not have a GPS source other than my GTX 335, which does not have serial output. But thinking about options has me pondering the merits of an Aera 760 to drive multiple devices.

I have a GTR-225 radio. Used to have a GDL 50 but Garmin bricked it. Right now I am using a Stratux, but I would consider buying a new GDL 50 if the benefits justified it. I am also going to install either an EI CGR-30P or a JPI EDM-830 engine monitor; leaning towards EDM 830 at the moment.

Aera 760 has 2 serial ports and audio out wires, plus wifi. So would all this work?

• Aera to GDL-50 on wifi or bluetooth for traffic and weather
• Aera to GTR-225 via serial port 1 for radio tuning
• Aera to AV-30C and JPI EMS via serial port 2 for HSI and fuel required
• Aera to GTR-225 via audio jack for alerts

 

[mondtster]

It's a minor nit to pick but the GTX335 does indeed have serial output. In this case it probably wouldn't offer much value to hook it up though. If it were a GTX345 that would be another story.

I've done installations where the Aera is receiving ADSB data from either a GTX or GDL both wirelessly or via serial. Both work. I've also done Aera to GTR via serial for frequency transfer and that works well too. The Aera audio out going to the built in intercom in a GTR also works fine. I haven't tried connecting an Aera to an AV30, but don't see why it wouldn't work. I've also never tried hooking an Aera to a JPI, as none of the aircraft I've done installations on have had one.

 

[Salty]

I just pulled the trigger on an AV-30C on sale for my Decathlon rebuild, and have been reading about NMEA input to drive the HSI. I do not have a GPS source other than my GTX 335, which does not have serial output. But thinking about options has me pondering the merits of an Aera 760 to drive multiple devices.

I have a GTR-225 radio. Used to have a GDL 50 but Garmin bricked it. Right now I am using a Stratux, but I would consider buying a new GDL 50 if the benefits justified it. I am also going to install either an EI CGR-30P or a JPI EDM-830 engine monitor; leaning towards EDM 830 at the moment.

Aera 760 has 2 serial ports and audio out wires, plus wifi. So would all this work?

• Aera to GDL-50 on wifi or bluetooth for traffic and weather
• Aera to GTR-225 via serial port 1 for radio tuning
• Aera to AV-30C and JPI EMS via serial port 2 for HSI and fuel required
• Aera to GTR-225 via audio jack for alerts

How will you use one port to do HSI and fuel at the same time? You can share a port for rx, but not tx.

 

[Ed Haywood]

How will you use one port to do HSI and fuel at the same time?

It is my understanding that one NMEA "talker" port can feed up to 3 "listener" ports with GPS data. But that is based on very brief browsing of the Googles.

 

[Salty]

It is my understanding that one NMEA "talker" port can feed up to 3 "listener" ports with GPS data. But that is based on very brief browsing of the Googles.

That’s correct. But aren’t you looking for two types of data from two different sources? Maybe I’m misunderstanding your use case.

 

[Ed Haywood]

That’s correct. But aren’t you looking for two types of data from two different sources? Maybe I’m misunderstanding your use case.

Not entirely sure I understand my own use case.

My idea is the Aera 760 would output GPS data in NMEA format to the AV-30C and EDM-830 as listeners. I think it can accomplish that using one serial port since the data stream is one way only.

The AV-30C is input only. It displays course line, heading, and waypoint ID.

The EDM-830 senses and self-configures for input or bi-directional data. If the EDM-830 is input only, then it calculates and displays fuel required to next waypoint/destination and MPG. If bi-directional, it sends fuel flow data back to the GPS Navigator for use in that device.

At least that is what I gather from an initial browsing of the install manuals.

 

[Salty]

Not entirely sure I understand my own use case.

My idea is the Aera 760 would output GPS data in NMEA format to the AV-30C and EDM-830 as listeners. I think it can accomplish that using one serial port since the data stream is one way only.

The AV-30C is input only. It displays course line, heading, and waypoint ID.

The EDM-830 senses and self-configures for input or bi-directional data. If the EDM-830 is input only, then it calculates and displays fuel required to next waypoint/destination and MPG. If bi-directional, it sends fuel flow data back to the GPS Navigator for use in that device.

At least that is what I gather from an initial browsing of the install manuals.

Ok, I thought you meant the other way. Yes, that should work fine.

 

[mondtster]

Not entirely sure I understand my own use case.

My idea is the Aera 760 would output GPS data in NMEA format to the AV-30C and EDM-830 as listeners. I think it can accomplish that using one serial port since the data stream is one way only.

The AV-30C is input only. It displays course line, heading, and waypoint ID.

The EDM-830 senses and self-configures for input or bi-directional data. If the EDM-830 is input only, then it calculates and displays fuel required to next waypoint/destination and MPG. If bi-directional, it sends fuel flow data back to the GPS Navigator for use in that device.

At least that is what I gather from an initial browsing of the install manuals.

As far as I know, as long as the data format used by both units receiving the GPS information is the same as what the GPS is transmitting you should be able to split the line and send information to both.

Also, you won't get heading out of the AV30 when you're displaying the course line. You'll have the ground track that is getting put out by the GPS displayed. The AV30 can be set up as a directional gyro but it isn't suitable to serve as a traditional CDI or HSI when it is connected to a GPS. It is basically going to indicate the same thing as what the indicator on the Aera is going to display.

 

[Ed Haywood]

The AV30 can be set up as a directional gyro but it isn't suitable to serve as a traditional CDI or HSI when it is connected to a GPS.

Not sure that I fully understand the distinction, but that's OK. I'm strictly VFR, so the DG display on the AV-30 is mostly for convenience. Could be once I see the difference in behavior, I disconnect it. I am looking forward to STC approval of the remote magnetometer though.

 

[mondtster]

Not sure that I fully understand the distinction, but that's OK. I'm strictly VFR, so the DG display on the AV-30 is mostly for convenience. Could be once I see the difference in behavior, I disconnect it. I am looking forward to STC approval of the remote magnetometer though.

Ground track and heading are two totally different things. Especially if there is any wind that you have to correct for. VFR pilots probably don’t care much but if ATC tells you a heading to fly they mean heading not ground track.

UAvionix does a poor job of telling you what you’re really getting with the AV30. I personally think that is intentional, so it sounds like it has more useable features than it does and that might trick some customers into buying an AV30 over a GI275 thinking it does the same thing. It does not.

 

[Ed Haywood]

Ground track and heading are two totally different things. Especially if there is any wind that you have to correct for. VFR pilots probably don’t care much but if ATC tells you a heading to fly they mean heading not ground track.

UAvionix does a poor job of telling you what you’re really getting with the AV30. I personally think that is intentional, so it sounds like it has more useable features than it does and that might trick some customers into buying an AV30 over a GI275 thinking it does the same thing. It does not.

Got it. I'm installing mine mainly for the AI, but the ability to switch to DG view might be handy for tasks such as visualizing pattern entry. Pure VFR stuff.

AV-30 and GI-275 are clearly different gadgets for different audiences. The AV-30 pilot's guide and install manual have multiple warnings stating "HSI mode for VFR only".

The HSI mode presentation is a bit confusing. Magenta lines show GPS course and deviation. Center line shows GPS ground track. Then it has Bearing To and Heading Bug on the top arc. Bearing To is direction from aircraft to waypoint, correct? So if aircraft heading is not displayed anywhere, should the "Heading Bug" actually be called Track Bug?

 

[mondtster]

Bearing To is direction from aircraft to waypoint, correct? So if aircraft heading is not displayed anywhere, should the "Heading Bug" actually be called Track Bug?

My experience with that page in the AV30 is limited, but as far as I know you are correct in that interpretation.

If you’re installing an Aera 760 there is a page that provides some basic attitude information and an “HSI” similar to what the AV30 provides. I wouldn’t fly instruments with them but it would possibly offer an option to get you out of a bad spot in a VFR only airplane. I’ve installed several in super Cubs and only retained the basic VFR instruments to keep weight to a minimum. It works well as an MFD of sorts.

Another thing you might consider instead of the AV30 is a GI275 MFD. I believe these can show some basic pitch information as well as be an engine monitor and a basic GPS with some navigation features as well.