Garmin G5 Review

[N201MKTurbo]

4 hours ago, OR75 said:

Can you point to where in the STC or in the install manual it says the G5 can be an encoder ? Thanks !

When I installed mine back in ‘17 the install manual had a line in it that specifically prohibited it. Perhaps they just removed that line. 
 

I believe it said you couldn’t use the serial output signal.

[OR75]

3 hours ago, N201MKTurbo said:

When I installed mine back in ‘17 the install manual had a line in it that specifically prohibited it. Perhaps they just removed that line. 
 

I believe it said you couldn’t use the serial output signal.

Looked at the air data section ... nothing that says that the G5 can be used as an encoder

[N201MKTurbo]

Just now, OR75 said:

Looked at the air data section ... nothing that says that the G5 can be used as an encoder

If you look at the serial messages available for output on the G5 and the serial input required by your transponder, you will find a match.

You seem to be of the new mindset that says unless it is specifically authorized, it is unauthorized. I would argue that unless it is specifically prohibited, it is OK.

[OR75]

18 minutes ago, N201MKTurbo said:

If you look at the serial messages available for output on the G5 and the serial input required by your transponder, you will find a match.

You seem to be of the new mindset that says unless it is specifically authorized, it is unauthorized. I would argue that unless it is specifically prohibited, it is OK.

Actually not in that mindset .

what section in the manual are you referring to. Legitimately not trying to find controversy ... just looking for the right section that will allow me to config. 

[N201MKTurbo]

16 minutes ago, OR75 said:

Actually not in that mindset .

what section in the manual are you referring to. Legitimately not trying to find controversy ... just looking for the right section that will allow me to config. 

I'm not trying to stir up trouble either. 

I'll look it up tonight and let you know.

[Ragsf15e]

9 hours ago, OR75 said:

Actually not in that mindset .

what section in the manual are you referring to. Legitimately not trying to find controversy ... just looking for the right section that will allow me to config. 

Yeah I’m not sure the exact wording either.  I know it was previously specifically not allowed and they took that line out.  Then when I was having my 2xG5s installed the faa certified avionics repair station told me they could use the G5 as the encoder.  I double checked with them since I knew about the previous prohibition, but they assured me it was ok.  Sorry, that’s the best I’ve got.

One nice thing about having the G5 as the encoder is that the reported altitude is spot on the indicated altitude you see on the device assuming you have the correct altimeter set.  The encoder I had previously was within limits but off by 150 feet or so.

[jamesm]

How would that would work?  hypothetical speaking. If your G5 Altitude is being corrected for barometric pressure  and possibly  for  Temperature if you have the GAD 13 .

If I am not mistaken.... Doesn't the Altitude encoder return an altitude to ATC with Altimeter setting 29.92" and no temperature correction and then get corrected on the ATC's end ?

I have noticed countless planes on the  the Ipad  with their altitude reading  waaay off. It annoys me having so much incorrect data being displayed.  I don't rely on it.

I couldn't possible see how the ATC's system could tell what altitude is being sent to it. whether  Altitude  that is corrected being for 29.92"  or Altitude from CAN Data or GPS altitude or  ????

Curios to know

James '67C

[OR75]

7 minutes ago, jamesm said:

How would that would work?  hypothetical speaking. If your G5 Altitude is being corrected for barometric pressure  and possibly  for  Temperature if you have the GAD 13 .

If I am not mistaken.... Doesn't the Altitude encoder return an altitude to ATC with Altimeter setting 29.92" and no temperature correction and then get corrected on the ATC's end ?

I have noticed countless planes on the  the Ipad  with their altitude reading  waaay off. It annoys me having so much incorrect data being displayed.  I don't rely on it.

I couldn't possible see how the ATC's system could tell what altitude is being sent to it. whether  Altitude  that is corrected being for 29.92"  or Altitude from CAN Data or GPS altitude or  ????

Curios to know

James '67C

The transponder sends an FL altitude (29.92) and ATC corrects using the nearest pressure setting .
If after giving you the local altimeter setting, they see a big difference between what you tell them your altitude is and what they calculate from what your transponder is sending them, they will ask you tu turn off the mode C 

at least, that’s my understanding 

I have a KT-74 and it can display the FL it is sending to ATC 

[jamesm]

as I understand it the "FL" pressue from encoder altimeter shown on the transponder. Not The same as baro corrected altimeter that we are supposed to fly by. They rarely agree with baro altimeter. My point is if someone were to send the altimeter reading from the G5 my guess is that ATC system would have no way of knowing what what altimeter reading source is. It could be a huge difference in altimeter reading.

[JimB]

A transponder should be transmitting pressure altitude to ATC. It should not be transmitting indicated or baro adjusted altitude. This keeps all the aircraft that are coming and going from various areas or atmospheric pressure with possibly different or erroneous altimeter baro settings consistent and separated. When a transponder encoder is checked every 2 years (91.413) it is checked at the standard setting. 

Edited February 9, 2021 by JimB

[Ragsf15e]

10 hours ago, jamesm said:

as I understand it the "FL" pressue from encoder altimeter shown on the transponder. Not The same as baro corrected altimeter that we are supposed to fly by. They rarely agree with baro altimeter. My point is if someone were to send the altimeter reading from the G5 my guess is that ATC system would have no way of knowing what what altimeter reading source is. It could be a huge difference in altimeter reading.

The G5 is sending pressure altitude to the transponder for transmission to atc (29.92).

It is displaying barometric altitude to the pilot assuming the pilot set the correct altimeter setting.

Atc’s radar will display the correct baro altitude of the aircraft by converting the transmitted pressure altitude using the local altimeter setting.

clear as mud?

[jamesm]

On 2/9/2021 at 4:32 AM, JimB said:

A transponder should be transmitting pressure altitude to ATC. It should not be transmitting indicated or baro adjusted altitude.

 Above is what I am trying to say. Thanks Jim.  though my original comment was a hypothetical one. I had heard something similar though it wasn't A G5 per say I think it was the Dynon system. The guy want  to send ATC the baro adjusted Altitude. Which I thought wasn't a good Idea. Unless the ATC had a way to distinguishing between  baro adjusted Altitude and pressure altitude (29.92") Altitude.

So the G5  you have  RS232 serial port which was explained to me is the means  of getting lat & long info to/from the  G5 display(s) of course depending on the setup and the configuration. I haven't in a while but I have in the past hooked up my laptop to G5's serial bus to see what word strings are being transmitted.  I suspect it would be the GPS altitude on the serial bus. Or it could be  just pure GPS lat long data.  Then there is CAN data I haven't tried tapping that bus. I don't have any fancy CAN Bus break out and monitor adapters (CAN to RS232) to  see what data is there.   Any rate If the adjust baro  altitude is on the CAN bus you would need some  way to convert to gray code or something the Transponder understands before  that data gets broadcast to  ATC radar . Unless Garmin Transponder's do this onboard.  

 

Didn't mean to hi-jack the thread. I thought I was missing something.

James

Edited February 11, 2021 by jamesm

[OR75]

On 2/8/2021 at 5:49 PM, Ragsf15e said:

Yeah I’m not sure the exact wording either.  I know it was previously specifically not allowed and they took that line out.  Then when I was having my 2xG5s installed the faa certified avionics repair station told me they could use the G5 as the encoder.  I double checked with them since I knew about the previous prohibition, but they assured me it was ok.  Sorry, that’s the best I’ve got.

One nice thing about having the G5 as the encoder is that the reported altitude is spot on the indicated altitude you see on the device assuming you have the correct altimeter set.  The encoder I had previously was within limits but off by 150 feet or so.

I believe I understand why/how you are able to use the G5 as an encoder .... 

the key is that you have 2 G5s ...

the primary G5 is likely connected to a GPS source via the Rs232 in port. It is likely configured as MapMX and that sets the clock of the RS232 in / out to 48,000 baud . That’s makes the out port not configureable to serial encoder ( which requires 9600 baud) . I am not sure why the RS232in/out must have the same clock. 

the second G5 does not need any connection and you can configure its  RS232 port out to serial encoder 

if a G5 is not connected to a GPS source ( but to an external antenna) than the Rs232 out can be set to encoder 

[Ragsf15e]

19 hours ago, OR75 said:

I believe I understand why/how you are able to use the G5 as an encoder .... 

the key is that you have 2 G5s ...

the primary G5 is likely connected to a GPS source via the Rs232 in port. It is likely configured as MapMX and that sets the clock of the RS232 in / out to 48,000 baud . That’s makes the out port not configureable to serial encoder ( which requires 9600 baud) . I am not sure why the RS232in/out must have the same clock. 

the second G5 does not need any connection and you can configure its  RS232 port out to serial encoder 

if a G5 is not connected to a GPS source ( but to an external antenna) than the Rs232 out can be set to encoder 

Could be, I’m not sure.  The two that I have are connected together and to the autopilot, gad29, gmu11.

[bradp]

Look at Garmin Steve’s answer here regarding baud output on rs-232 and the ability to transmit pressure over a429 label 203 to compatible transponders. 
 

I’ve tried to see if I could get rs232 to transmit altitude over 48000 to my 430W in the past and I could not get this to work.  
 

https://www.beechtalk.com/forums/viewtopic.php?f=21&t=148889

[Ragsf15e]

8 hours ago, bradp said:

Look at Garmin Steve’s answer here regarding baud output on rs-232 and the ability to transmit pressure over a429 label 203 to compatible transponders. 
 

I’ve tried to see if I could get rs232 to transmit altitude over 48000 to my 430W in the past and I could not get this to work.  
 

https://www.beechtalk.com/forums/viewtopic.php?f=21&t=148889

My G5 does send altitude to my 430w.  When I go to the density altitude/TAS computation page, altitude auto populates and exactly matches current g5 indicated.  Altimeter setting however does not automatically populate...

[bradp]

8 minutes ago, Ragsf15e said:

My G5 does send altitude to my 430w.  When I go to the density altitude/TAS computation page, altitude auto populates and exactly matches current g5 indicated.  Altimeter setting however does not automatically populate...

That’s good to know.  I’ll try again.  I think since mine has a Gray code input spliced in from the encoding altimeter that may be the priority. 

[Ragsf15e]

2 hours ago, bradp said:

That’s good to know.  I’ll try again.  I think since mine has a Gray code input spliced in from the encoding altimeter that may be the priority. 

Indicated airspeed and altimeter setting dont auto populate for me in the 430w.  The temp is coming from my jpi930, and altitude from the g5.  I supply the altimeter setting and calibrated airspeed.  

[Ragsf15e]

After reading that whole BT thread, it appears that the G5 will only work as an encoder for certain transponders (using 429, like gtx345, gtx330, etc) if you have it connected to a garmin gps using Mapmx.  If you don’t have it connected using Mapmx, it can output pressure altitude on serial at the correct baud to other transponders.  Clear as mud?

Edited February 16, 2021 by Ragsf15e

[carusoam]

While on BT...

Seek out Trek Lawler... @TrekLawler

He is the Big G guy in charge of connecting the internet to Big G...

He is soooo busy,people have to go to him... unfortunately...

Best regards,

-a-

[OR75]

29 minutes ago, Ragsf15e said:

After reading that whole BT thread, it appears that the G5 will only work as an encoder for certain transponders (using 429, like gtx345, gtx330, etc) if you have it connected to a garmin gps using Mapmx.  If you don’t have it connected using Mapmx, it can output pressure altitude on serial at the correct baud to other transponders.  Clear as mud?

The G5 does not have arinc 429 .  The Arinc 429 out will come out of the GAD29B 

If your transponder accepts 429 .... it can get pressure altitude from the GAD 29B

if your transponder only accepts serial RS232 ... you can use a G5 if does not have the MaPMX input used. If you have 2 G5s , then you can use the G5 that is not receiving MaPMX ( MaPMX is only needed for 1)

[topflight]

On 12/6/2016 at 9:02 PM, FlyboyKC said:

I believe the G5 comes with an internal GPS (which is disabled when its coupled with the 430). With the way GPS technology is these days it probably doesn't need an external antenna. The cost installed was $2,500 to couple with the 430. Since I had a new Garmin GTX 345 transponder installed at the same the IFR certification was included in the total cost.

 

[topflight]

The G5 requires an external antenna. The uavionix doesn’t. If you add a G5 for at the HSI it requires the magnometer  the uavionix doesn’t. But you then can get rid of the vacuum system. The antenna and magnometer are about $300 each. 

[jetdriven]

2 hours ago, topflight said:

The G5 requires an external antenna. The uavionix doesn’t. If you add a G5 for at the HSI it requires the magnometer  the uavionix doesn’t. But you then can get rid of the vacuum system. The antenna and magnometer are about $300 each. 

The G5 and the AV30s are not the same category of product.  The G5 doesnt require an external antenna, it can uese the GPS for aiding.

The AV30 is also a DG, not a full featured HSI. You must set it, and it drifts, just like a vacuum DG.

[Ragsf15e]

18 hours ago, topflight said:

The G5 requires an external antenna. The uavionix doesn’t. If you add a G5 for at the HSI it requires the magnometer  the uavionix doesn’t. But you then can get rid of the vacuum system. The antenna and magnometer are about $300 each. 

External antenna is only required for the G5s if you don’t supply a gps input for it (yes, that gps would have its own antenna).  If you do provide the Garmin antenna for the G5, it’s mounted inside the airplane.  
Ive had dual G5s for 2 1/2 years and they’ve been solid.  Zero issues with the batteries or anything else.  They work perfectly with my stec 30 ap as well.