I recently received a MRX and was using it for the first time today.

When I selected the LOC button, the SQK code was different and had no relationship to the one assigned by ATC. I confirmed they were receiving a correct code. The TRA screen indicated the correct altitude which, from my understanding, emanates from the transponder's encoder.

Every time I accessed the LOC button, the SQK code numbers changed or simply read 0000.

I recently had my static system checked and my transponder/encoder were certified.

Would appreciate any suggestions as to how to deal with this matter.

I've also been experiencing difficulties posting on this site. If this message has repeated itself, my apologies and the web master is welcome to delete the messages as they see fit.

Thank you.

First, we must state unequivocally that the MRX should never be used to try to troubleshoot any certified equipment i.e. transponders. You did the right thing by calling ATC to verify your squawk code. While the MRX can usually pick up the host aircraft transponder squawk with little or no trouble, its priority will always be on finding traffic.

Secondly, you should understand that transponders are designed to be read clearly miles away from the source, not feet from the source which is exactly what we are trying to do. The signal coming from your transponder does not fully mature until it is farther away from your plane, thus the MRX can display a garbled code. The more important indicator for correct operation of the MRX was the TRA seen before the altitude in local information. That means the MRX is picking up your transponder and using the encoded altitude for traffic detection.

One simple solution is to clean off any dirt, oil, or debris that may have built up on your transponder antenna. From a close range the debris can garble the information from your transponder.

If you are still having trouble call our tech support 1-800-496-9430

Thanks

hello I'm fred from france
I baught today a zaon mrx ( june 3rd 2010 )
I have exactly the same problem : another sqwak code and the correct altitude TRA FL... from my filser xpdr.
did you resolve the problem ?
thanks for you reply
best regards
fred

Hello,
I have exactly the same problem: my pcas MRX indicates good TRA FL, but doesn't indicate the good squawk. My unit is new and firmware 2.9.
Thanks for your answer...
Brgds.

Sorry for the delay in responding --- however, I did manage to get my unit to recognize the Squawk Code by simply doing a thorough cleaning of my transponder blade.
The unit has been preforming flawlessly since.
Hope your solution is as easy as mine was.
Regards,
Pylet