GTN 750 Display Update Frequency

[DannyR 35]

Does anyone know what the update frequency is for the GTN 750?  By update frequency I mean how often the display information is updated.  I am experiencing what I believe to be slow updates to the relative position of the aircraft and wind speed direction.  I have looked in the user guide with no luck.

Regards,

 

Danny

[fppilot 4,360]

6 hours ago, DannyR said:

Does anyone know what the update frequency is for the GTN 750?  By update frequency I mean how often the display information is updated.  I am experiencing what I believe to be slow updates to the relative position of the aircraft and wind speed direction.  I have looked in the user guide with no luck.

Regards,

 

Danny

DAnny,

My display is smooth and continuous.  I do not notice updates.  In regard to the wind speed and direction, I believe it is read from the simulator, which in turns uses information from your weather engine.  I use FS Global Real Weather. There are certainly others available.

The weather engines I am aware of pull winds from online wind matrix's. Winds aloft winds are based on forecast wind direction and speed from gradients, which at most times have some width to them in terms of distance.  So it takes time to pass through one and into another.  That is the reason the wind pointer and wind pointer update occasionally. Upon the occasion of passing from one into another.

Here is a link to maps that depict gradients.  Note there is a drop box above the map for use in choosing winds at specific altitudes.

http://aviationweather.gov/windtemp/plot

[RXP 2,338]

Hi, what is your definition of 'slow' ?

Nominally, the screen refreshes around 25Hz, the wind around 1-2Hz (not only because the GTN reads inputs at this rate, but also because it averages the inputs over time).

There is a GUI Settings Panel option in 'Gauge | Advanced | Reduce Refresh Rate' meant to halve the updates for lower end system (very lower end systems).

[DannyR 35]

Slow means while in a helicopter in a hover if I turn slowly, very slowly, the wind direction indicator doesn't change its indication as I turn the helicopter.  The same issue occurs if I turn while flying, not in a hover.  The wind direction indication lags behind the aircraft heading changes by a noticeable amount.  Yet, there have been occasions where the wind direction will change abruptly in both direction and speed.  This I expect is more associated with the weather engine I am using (ASP4).

Danny

[RXP 2,338]

When using the GTN in 'helicopter mode', there are different internal 'thresholds' for such things. For example most computations require aircraft moving above a minimum speed, and with helicopters, the GTN switches to other limits especially when hovering.

To make sure you are in 'helicopter' mode, you just have to select and reboot the device (or ensure it is auto detected) a 'helicopter' aircraft icon. There should be a 'H' mention as well somewhere either in the boot screens or  the system pages.

Having said this, wind gets updated slowly over time, this is how the GTN deals with changes internally.