API Question oapiGetNavSignal values and com/nav mfd

[nitro]

Does anyone know what the relations is between the value of the api function oapiGetNavSignal and how many bars are displayed in the Com/Nav mfd? Or does it use something else?

And also what is the maximum value of the signal strength?

 

[vdrorb]

Does anyone know what the relations is between the value of the api function oapiGetNavSignal and how many bars are displayed in the Com/Nav mfd? Or does it use something else?

And also what is the maximum value of the signal strength?

i just copy the part of the docu, maybe it helps :hello:
so far i understand it depends on the "power" of your nav signal, see below "power (type double) - in the definition of your nav signal", so when you 'stand' on the nav signal (r=0) you will get a signal strength "S(r=0)=ndata.power" of the the full power, which nromaly is signal_max_radius^2

and to be complete in the answer: For the Bar-Graph display i dont know, but if you realy want to know, i think of two possibilties a) a small LUA-script mfd that is printing the the signal strength (and ndata.power) and writing down when the next bar is displayed. b) the programmer is telling you (or you have the source code) ... but all in all, since the strength changes with r^2 i would expect some sort of logarithmic scale of (1-maxpower)

:tiphat:

Detailed Description
Navigation transmitter data.
This structure contains both general data (transmitter type, channel, output power and description string) and type-specific data. To query type-specific data, first check the transmitter type, for example

NAVDATA ndata;
oapiGetNavData (hNav, &ndata);
if (ndata.type == TRANSMITTER_ILS)
approach_dir = ndata.ils.appdir;

Note:
The power S0 of a transmitter is defined in arbitrary units such that the signal S(r) = S0/r2 drops to 1 at the maximum range rmax, given a default receiver, i.e. S0 = r2max.




Public Attributes
DWORD type
transmitter type id

DWORD ch
transmitter channel (0..639)

double power
transmitter power [arbitrary units]

const char * descr
pointer to transmitter description string

 

[nitro]

Thanks for the information. I have a working indicator, but I would like to have it in sync with the com/nav mfd. I think having a lua script to show me the raw values in orbiter is my best option for now. Unless Martin stops by and gives me the numbers.

 

[martins]

Number of bars in NAV/COM MFD:

sig = max(0,min(5,1+(int)(0.5*log(nav->FieldStrength(vessel->GPos())))));

where "FieldStrength" is the value that oapiGetNavSignal returns.

As for the maximum signal, that has a singularity at distance=0. (I am assuming point sources).

 

[nitro]

Thanks a lot. Now I can make an indicator that matches the MFD.