FlightDeck

Thank you for your offer. However, I believe that no matter the sentence used, my GPS will modify the altitude value. I have to find a way to turn off this feature or to live with. Best regards

AV400 do not work with my Avmap EKP-IV. This mode does not generate any parameter at all on the GPS. The only FSUIPC4 selectable sentence that provide altitude in my case is $GPGGA. Note that the altitude provided by FSUIPC4 sentence $GPGGA is exactly the same than the FSX altitude. I found that my GPS modifies the information displayed. It seems to be a WGS84 ellipsoid Avmap built in feature. Thank you for your support.

Airport: VOMM, Chennai, India FSX Altitude: 57.7' Avmap EKP-IV: 339' Difference : 281.3' ( 85,74 M ) Airport: VEBA, Behala, India FSX Altitude: 8' Avmap EKP-IV: 184' Difference : 176' ( 53,64 M ) Airport: VCCT, Trincolalee, Srilanka FSX Altitude: 10.7' Avmap EKP-IV: 313' Difference : 302.3' ( 92,14 M ) Airport: WAWW, Wolter Monginsidi, Indonesia FSX Altitude: 167.7' Avmap EKP-IV: -5' Difference : -172.7' ( -52,64 M ) Amazing! WGS84 seems the only mode available But at least one thing is sure, it's not FSUIPC4

I did new tests with FSX I notice that altitude offset changes according to my position on ground. Exemple: Airport: CSK3, Mascouche, Canada Runway : 29 FSX Altitude: 78.7' Avmap EKP-IV: 185' Difference : 106.3' Airport: CYUL, Montreal, Canada Runway : 06L FSX Altitude: 121.7' Avmap EKP-IV: 229' Difference : 107.3' Airport: KJFK, New-York, USA Runway : 04L FSX Altitude: 16.7' Avmap EKP-IV: 128 Difference : 111.3' Airport: CYVR, Vancouver, Canada Runway : 26L FSX Altitude: 17.7' Avmap EKP-IV: 76' Difference : 58.3' Airport: KEYW, Key West, Florida, USA Runway : 9 FSX Altitude: 6.7' Avmap EKP-IV: 86' Difference : 79.3' Airport: SPLP, Las Palmas, Lima, Peru Runway : 29 FSX Altitude: 5087.7' Avmap EKP-IV: 5055' Difference : 33.7' In some airport, my GPS even displays negative altitude! That means my GPS apply an altitude offset in relation with the location. May be it's a built in correction table? I did not found any setup for that. My initial argument was based on tests made from one position (CSK3) in FSX. This new test shows clearly that my GPS apply a different altitude offset in relation with the location on earth. Kind of satellite elevation correction table?

My GPS is an « Avmap EKP-IV » http://www.avmap.us I will investigate my GPS and try to understand why the altitude displayed is always 106' higher. May be a setup? If not, I will contact Avmap. Navigation. This situation does not occur with the antenna. Seems logic it is not your module because this kind of problem would have been identified long time ago on this forum! Thank you very much for your answer and for your fantastic contribution to the sim and real world flight communities.

Your software (FSUIPC4) works perfectly with my Avmap EKP-IV GPS. It's a great tool that allows me to learn and practice safely all the functionalities of my GPS before a real flight. But the altitude displayed by my GPS is always 106 feet higher (+/- 32 meters) that the altitude received by the $GPGGA sentence (example : 1000' = 1106', 1500' = 1606', 2000' = 2106', etc.) or the altitude display by FSX " shift Z " function. That means that my GPS add +/- 32 meters (106 feet) to the altitude value received. I have read on the Web that the altitude computed from GPS satellites signal are corrected with a theoretical MSL (Mean Sea Level) offset of +/- 32 meters. http://www.esri.com/news/arcuser/0703/geoid1of3.html Does it means that FSX altitude should be decreased by 32 meters to emulate the signals broadcasted by GPS satellites? If yes, what do you think about a selectable checkbox for this offset in a future revision of FSUIPC4 ? If not, does it means that my GPS do not process altitude as others GPS ? Best regards