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Darinh

Well Known Member
I have a D100 connected to a GTX327 and have been flying this setup for 50 hours now. I went up the other day and the tower asked if I had Mode C...Affirmative was the reply to which he replied that he was getting a good transponder signal but no altitude.:confused: Like I stated, this setup has been flying for 50 hours and I have not touched a thing and this is the first time the tower has told me I wasn't encoding altitude.

Is there a way to check on the ground if the Tx is receiving the altitude from the Dynon? When they are both powered up, the Tx indicates PA so I would assume this tells me that the Dynon encoder is working as it should or is this a bad assumption? If this in fact the case, the issue should be in the Tx. Is my thinking here logical or not. Any ideas?

Darin
 
G327 has a configuration mode where you can display the raw altitude it's receiving from the encoder; check the manual for this.

My 327 started reporting whacky altitudes recently. Didn't appear to be the encoder or wiring. Sent the unit out to Garmin, they upgraded the firmware, problem seems to be solved. Strange... :confused:

TODR
 
If the transponder is showing altitude on its display, then it's receiving data from the encoder (in this case Dynon). That would imply that either your transpoder is bad or you had it somehow set to Mode A instead of C (ie. pressing "On" instead of "Alt" button)

edit: the altitude display can be confirmed on the ground.. you do not need to go flying for that. If Dynon isn't sending encoder data to it, the altitude display will be blank.. even on the ground.
 
TODR,

I checked this last night and found both the page that shows gray code altitude output and serial (RS232) output and hence my question that if the Tx is showing an altitude is the Dynon encoder working correctly. The answer you provided is yes, my Dynon is working as it should.

Radomir,

I didn't think of this and that could very well be the problem. I don't have my manual here with me but does the Tx display on the screen whether it is encoding mode s or mode c? If not clearly displayed on the screen, is there a way to check which mode it is operating in?

Thanks for the reply by the way, both of you.

Darin
 
Darinh said:
TODR,

I checked this last night and found both the page that shows gray code altitude output and serial (RS232) output and hence my question that if the Tx is showing an altitude is the Dynon encoder working correctly. The answer you provided is yes, my Dynon is working as it should.

Radomir,

I didn't think of this and that could very well be the problem. I don't have my manual here with me but does the Tx display on the screen whether it is encoding mode s or mode c? If not clearly displayed on the screen, is there a way to check which mode it is operating in?

Thanks for the reply by the way, both of you.

Darin
Click to expand...

If the G327 is getting the right altitude info, the thing to check is (1) if it's giving replies and (2) if it's on Mode A or Mode C (I assume you mean Mode C and not Mode S since the 327 isn't Mode S).

On the G327, the reply light (i.e., the transponder is replying to an interrogation) is a circle with a "R" in it on the lower left of the display.

The mode part of the display is to the left of the transponder code. It will either show "ALT" for Mode C or "ON" for Mode A.

Hope you can resolve it easily.

TODR
 
TODR,

Sorry...mode A is what I meant. Thanks for the help. I did see the enscribed R for the transponder and the tower did say that the transponder was strong but I don't remember if I saw the "Alt" or "On" indication. I will check it tonight. Thanks again,

Darin
 
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