GPS VOR1 Localiser Question 2AAC Offset

[Pierreprototype]

Good evening Pete,

 

Once again thanks for a GREAT product!

 

I have a small problem. When I read offset for Vor 1 localiser (2AAC tested on FSUIPC Interrogate) on a dialed up nav freq ie 117.40 for FALA I get the correct value in range of -127 to +127 for the localiser needle to be sent to my third party stand alone gauges. However when I click the nav/ GPS switch, the gauge on the flight sim panel (VOR1) shows a corresponding offset to that of the CDI on the GPS  (mindstar gns430), but if I read 2AAC when in "GPS" mode I get a zero value, yet the localiser on the panel shows the correct fly left / right information.

 

I have tested this issue with P3D (with mindstar gps) and FS9 with MSFS GPS and the issue prevails on both.

 

Any ideas? Do the flight sim panels VOR calculate a CDI value from some other data when in GPS mode?

 

 

 

 

[Pete Dowson]

I have a small problem. When I read offset for Vor 1 localiser (2AAC tested on FSUIPC Interrogate) on a dialed up nav freq ie 117.40 for FALA I get the correct value in range of -127 to +127 for the localiser needle to be sent to my third party stand alone gauges. However when I click the nav/ GPS switch, the gauge on the flight sim panel (VOR1) shows a corresponding offset to that of the CDI on the GPS  (mindstar gns430), but if I read 2AAC when in "GPS" mode I get a zero value, yet the localiser on the panel shows the correct fly left / right information.

 

I have tested this issue with P3D (with mindstar gps) and FS9 with MSFS GPS and the issue prevails on both.

 

Any ideas? Do the flight sim panels VOR calculate a CDI value from some other data when in GPS mode?

 

The original offset dating back to FS98 days is 0C48,  Did you check that too?

 

In FSX & P3D, it derives from the SimConnect variable, "NAV CDI:1", and as the name and description in the offsets list implies, it is associated with NAV1, not necessarily also the GPS.

 

Have you checked the HSI CDI needle value, offset 2F88.  In FSX and P3D that's from the SimConnect variable "HSI CDI NEEDLE", so it may well reflect what the instrument should show rather than what the NAV / VOR signal tells it.

 

Otherwise, sorry, Sorry, I have no ideas. You need to talk to someone who programs gauges to see what information they get.  Maybe there's an aircraft design forum on AVSIM?

 

Pete

[spokes2112]

Pete is correct, if using HSI CDI it takes whatever is slaved to NAV1 be it VOR1 or GPS. Getting NAV CDI:1 ( or derivatives ) will always produce what is coming from the nav radio regardless of being slaved by GPS for the AP.