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Get NAV frequencies (VOR or LOC ) in nasal

Nasal is the scripting language of FlightGear.

Get NAV frequencies (VOR or LOC ) in nasal

Postby yanes » Tue Jan 10, 2017 4:38 am

Hi all ,
the Su-27SK ARC navigation radio takes 8 :shock: Nav freqs as input that should be entered and set in the pre-flight preparations .
3 freqs for airfields (Main, alternative & emergency) and the othres for lateral navigation .
I plan to make a canvas dialog that takes just the nav stations from the pilot and searches for the correspending freqs .
So I think it would be easier (and faster) to a pilot to enter just the station or runway name and I wil code the scripts that fills
the system props with the necessary data ,
So how to get the freq if I have (for example) : "KSFO 28R "or "KSFO" as VOR name ?
How do you find the idea itself ?
is it worth of the work to be done :roll: ?

:?: And BTW , the manual say the frequencies are in couple for INNER and OUTER beacons , DOES this means the LOC and GS beacons or the Airport VOR and Rwy LOC ?
or may be something else ??
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Re: Get NAV frequencies (VOR or LOC ) in nasal

Postby PINTO » Tue Jan 10, 2017 6:31 am

To get the nearest, you could use findNavaidsWithinRange(). (http://wiki.flightgear.org/Nasal_librar ... ange.28.29)
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Re: Get NAV frequencies (VOR or LOC ) in nasal

Postby Johan G » Tue Jan 10, 2017 7:42 pm

yanes wrote in Tue Jan 10, 2017 4:38 am: :?: And BTW , the manual say the frequencies are in couple for INNER and OUTER beacons , DOES this means the LOC and GS beacons or the Airport VOR and Rwy LOC ?
or may be something else ??

A typical ILS equipped runway have four or five transmitters and related antennas: The outer, middle and (sometimes) inner marker beacons, glide slope and localizer.

The outer and middle marker beacons are directed upwards and usually marks the final approach fix (FAF) and when the aircraft passes the decision height (DH) (provided the aircraft is on the glide slope). The inner beacon is not always present, so I would guess your INNER and OUTER refer to the middle and outer beacon, though I could be wrong. The glide slope antennas are located by the touch down zone of the runway and the locator antenna is located beyond the far end of the runway.

The marker beacons uses fixed frequencies as they are low powered and directed upward and thus do not interfere with nearby beacons. The glide slope and localizer frequencies are paired so that the receiver will automatically tune in both of them.

While many airports have a VOR beacon, it is typically not related to the ILS system.

Some related Wikipedia articles: Instrument landing system (perm), Marker beacon (perm) and Instrument landing system glide path (perm).
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Re: Get NAV frequencies (VOR or LOC ) in nasal

Postby yanes » Wed Jan 11, 2017 1:09 am

Thanks really guys ,
I appreciate your help ,
@PINTO :The Nasal Lib is great ,It does almost exactly what I want .
@JohanG :Thanks , this was a bit confusing ,So I proceed pretending that these are the LOC and GS transmitters,

and what about the idea? Is it helpful to a pilot to take the Nav aids names or let him copy the freqs ?

Regards ,
Yanes Bechir
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Re: Get NAV frequencies (VOR or LOC ) in nasal

Postby Johan G » Wed Jan 11, 2017 12:09 pm

You are welcome! :)


Another possible explanation for INNER and OUTER that I did not think of yesterday is that they could be approach NDBs (non-directional beacons).

Prior to ILS become the common instrument navigation on aporoaches, an NDB beacon located on the approache was used together with the ADF instrument. To cover both runway directions there would be one on each approach to the runway.

In many airports with ILS approaches those aporoach NDBs are still there, though more like an emergency backup.

I have noted that while VOR beacons are more common in the west, NDBs are the prevalent type of beacons in Russia, probably due to their longer range. Given that, I would guess that NDB aporoaches might be as common as ILS approaches. Considering that the Su-27 pilot would enter com radio frequencies for both destination, alternative and emergency airports, it would not be unlikely that INNER amd OUTER could be the frequencies for the NDB beacons on the approaches from either direction to the planned runway.


As for wether or not you would automate the airport frequency lookup, I would say both. ;)

Some resources on NDB approaches: [NDB] Instrument Approach Plates and Non-Directional Beacon (NDB) Approach.
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