Hello dear CalGnome client,

only recently I learned - sadly so late -, that there is a problem in the data communication between LX7/8/9nnn devices and the CalGnome.

At this time, based on my notes about your order of the CalGnome and my fulfilment, I cannot see whether or not you are using a LX7/8/9nnn with built-in FLARM as source for the FLARM data stream feeding the CalGnome.

If that is NOT the case, then you may disregard this article altogether.

If, however, you run such a configuration in your plane (or plan to run such a configuration after a future instrument panel rebuilt), your CalGnome will/would not be able to work as designed.


LX7/8/9nnn devices are not 100% compatible with original FLARM devices; they do not emulate the FLARM data stream completely. One NMEA data sentence is omitted. Instead, the LX sends proprietary data sentences. The CalGnome firmware is - was - dependent on that specific data sentence, as the flight altitude was derived from that very sentence.

Four years ago, when the CalGnome development was in its final stage, LX-Red-Boxes and all other LX FLARM data sources were 100% compatible with the original FLARM. This is why - evidently with too much naïvety - I assumed the newer LX8/9nnn devices were built to comply to that FLARM standard also. As I learned recently - sadly so late -, they are not.
So far the bad news.

Now the good news :
Meanwhile, I have changed and updated the CalGnome firmware in such a way, that the program is not anymore dependent on that sentence. Altitude is now derived from another sentences in the data stream. The only "downside" of this remedy is, altitude precision is now in meters, not in feet as before. I am sure this does not hamper the usability of the CalGnome.


This is why I ask you to return the CalGnome to me. I would like to update the firmware of your CalGnome and return it to you - as soon as possible and at no extra cost. I suggest you get in contact with me first, so that we can arrange for a smooth update process.


The FLARM data stream through the CalGnome remains untouched by the update.
Updated CalGnomes are not restricted to be used with LX devices only.
They remain fully compatible with all other FLARM data sources.


I sincerely apologize for the hassle this creates.


Horst Rupp


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