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Bug or Feature?

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Bug or Feature?

Postby WoodSTokk » Tue Nov 07, 2017 4:19 pm

The value of '/instrumentation/nav/signal-quality-norm' should show the input strength of radio signal.
If i switch the frequency on nav from a nearly station to a frequency where no station is sending,
the 'signal-quality-norm' is inertial and take 2 or more seconds to fall from 1.0 to 0.0.

Imagine i take a FM radio with 2 programmed frequencies and i switch from a frequency with
local radio broadcast to the another frequency where no broadcaster is sending, i hear immediately noise.
This means the signal strength drop immediately to 0.

It looks like the '/instrumentation/nav/in-range' change the state if the 'signal-quality-norm' is below a certain value.
So it takes 2 or more seconds until the 'in-range' change the state.
Also the most other values in '/instrumentation/nav/' will be calculated.
This lead us too radio equipment (like RMI, HSI and so on) that point to stations that the equipment normaly has never heared.

Also the '/instrumentation/nav/heading-needle-deflection' looks like a inertial value.
Why isn't this value immediately droped to zero? If everyone has a mechanical gauge (like the glide sloop indicator) where the pointers
should slowly change, that he/she can write a filter for it.

I think that the values that was delivered from FG should allways reflect the real and actual values.
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Re: Bug or Feature?

Postby Johan G » Sun Nov 12, 2017 7:05 pm

Late and probably not useful answer:

One possible reason could be that the properties maybe are calculated with fairly long intervals and in different loops.
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Re: Bug or Feature?

Postby WoodSTokk » Wed Nov 15, 2017 2:25 pm

No, there are no fairly long intervals. The value will be updated more then 10 or 20 times per second.
I think it has to do with the signal-quality calculation while the radio is on one station. I asume that the result of the calculation can dramatically jump from one moment to the next.
To sort that out, all values go into a buffer and will be filtered to smooth out the peaks. Thats good make it more realistic.
The problem is, if you change the frequency, you have old values in the buffer and the new calculation is based on values that was never from this station.
As a fix, if the frequency is changed, the buffer should marked as invalid. The first value from quality calculation to the new station should populate the whole buffer and delete the invalid flag.
But this is only a logical assumtion from me.
But the developer can look at the code from ADF. If i change the frequency on ADF, 'in-range' switches immediately to 'false'.
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