ILS DME

[Joni]

Hi guys,

 

After catching GS the HUD no longer displays DME, so if the airport doesnt have TCN then you have no clue where you are.

 

Bug? Mirage fault?

[jojo]

Maybe both...

 

The HUD should display DEST waypoint range, even in APP mode (approach).

 

There is no dedicated DME on the Mirage 2000, you have to use TACAN to read DME range.

 

In this link you will find a table with associated ILS/DME /TACAN frequencies & channels.

http://wiki.radioreference.com/index.php/Instrument_Landing_System_(ILS)_Frequencies#Distance_Measuring_Equipment_.28DME.29

 

For instance, if ILS frequency is 108.10Mhz then DME frequency is 1042MHz - 979 MHz = TACAN channel 18X

- VOR.ILS box = set 108.10

- TACAN box = set T/R & X18

- IDN (HSI) = set TAC (Cv NAV/ NAV/ TAC/ρ / Θ)

 

You should read:

- HUD: "DEST" INS range + ILS box (LOC & GS)

- ADI ball: LOC and Glide Slope needles

- IDN: DME range

[Joni]

Maybe both...

 

The HUD should display DEST waypoint range, even in APP mode (approach).

 

There is no dedicated DME on the Mirage 2000, you have to use TACAN to read DME range.

 

In this link you will find a table with associated ILS/DME /TACAN frequencies & channels.

http://wiki.radioreference.com/index.php/Instrument_Landing_System_(ILS)_Frequencies#Distance_Measuring_Equipment_.28DME.29

 

For instance, if ILS frequency is 108.10Mhz then DME frequency is 1042MHz - 979 MHz = TACAN channel 18X

- VOR.ILS box = set 108.10

- TACAN box = set T/R & X18

- IDN (HSI) = set TAC (Cv NAV/ NAV/ TAC/ρ / Θ)

 

You should read:

- HUD: "DEST" INS range + ILS box (LOC & GS)

- ADI ball: LOC and Glide Slope needles

- IDN: DME range

Thanks.

 

Is that conversion real? Can you teach me more about how and why its done that way? :)

 

Enviado desde mi Moto Z Play mediante Tapatalk

[jojo]

I can only guess the space & weight was counted on the small Mirage 2000, and since TACAN can be used as DME it was accepted like that.

 

The TACAN/ DME equivalence is real and well known. The frequency/ TACAN channel equivalence table can be found in official aeronautical publications, I used wiki for ease of use on internet.

 

A civilian aircraft can use DME on TACAN station to get range, but he won't be able to get QDM/ QDR.

Reciprocally, a military TACAN can read civilian DME, but but not VOR.

 

So in Mirage we have 2 command boxes: VOR.ILS & TACAN.

 

On this official French Air Force page you can find the French airport "Listing DME", with runway DME and corresponding DME channel.

http://www.dircam.dsae.defense.gouv.fr/index.php/infos-aeronautiques/en-route-france

Edited November 27, 2017 by jojo

[Joni]

I can only guess the space & weight was counted on the small Mirage 2000, and since TACAN can be used as DME it was accepted like that.

 

The TACAN/ DME equivalence is real and well known. The frequency/ TACAN channel equivalence table can be found in official aeronautical publications, I used wiki for ease of use on internet.

 

A civilian aircraft can use DME on TACAN station to get range, but he won't be able to get QDM/ QDR.

Reciprocally, a military TACAN can read civilian DME, but but not VOR.

 

So in Mirage we have 2 command boxes: VOR.ILS & TACAN.

 

On this official French Air Force page you can find the French airport "Listing DME", with runway DME and corresponding DME channel.

http://www.dircam.dsae.defense.gouv.fr/index.php/infos-aeronautiques/en-route-france

 

I meant about how the conversion is done, I know the table but dont know the math.

[Joni]

I tested it on beslan and it didnt work. I used the table. Maybe dcs doesnt model this conversion?

[jojo]

I tested it on beslan and it didnt work. I used the table. Maybe dcs doesnt model this conversion?

 

I can't say I'm surprised ? (DCS World) :doh:

[Joni]

I can't say I'm surprised ? (DCS World) :doh:

Dont be mean, dcs has no bugs

 

Enviado desde mi Moto Z Play mediante Tapatalk

[Frederf]

Let's see if one can reduce table to a numbers trick:

 

"Channel less than sixty, add ten sixty-three (1063). Seventy and more, ten off the score. For Y an extra point-oh-five."

 

71Y is 1063 + 71 - 10 = 1124 or 112.40, Y so 112.45.

[=Pedro=]

Let's see if one can reduce table to a numbers trick:

 

"Channel less than sixty, add ten sixty-three (1063). Seventy and more, ten off the score. For Y an extra point-oh-five."

 

71Y is 1063 + 71 - 10 = 1124 or 112.40, Y so 112.45.

 

Nice one! :D

[drPhibes]

I tested it on beslan and it didnt work. I used the table. Maybe dcs doesnt model this conversion?

 

If you're talking about ILS+DME(TACAN) channel pairing, that isn't really relevant at Beslan, as there is no DME or TACAN there (at least according to Lino's beacon map). And the channel pairing is only relevant for DMEs co-located with the GP (terminal DME), which isn't the case for the TACANs spread around the Georgia map (they're set up as enroute navaids, despite being located at the airfields).

 

Edit: and yes, I'm using a mix of the terms DME and TACAN here. As far as distance measurement goes, it's the same thing, operating on the same frequencies with the same signal specs.

 

Edit 2: and regarding the channel pairing only being relevant for terminal DME: I am of course referring to the DME channels paired to ILS frequencies, not VORs. Just so that's clear.

Edited November 28, 2017 by drPhibes

[gospadin]

Edit 2: and regarding the channel pairing only being relevant for terminal DME: I am of course referring to the DME channels paired to ILS frequencies, not VORs. Just so that's clear.

 

Yup, it's the same math for pairings in either case.

 

https://www.ntia.doc.gov/legacy/osmhome/redbook/4d.pdf

[Frederf]

You won't get DME services out of Beslan with any airplane because there's no DME service there. The ILS is markers only for distance.

 

Mirage of course has DME transponder equipment. It appears to be permanent associated with the TACAN entry (not switching to frequencies paired to ILS entry at any time).

 

If you want to test if Mirage has robust systems modeling then one can try to use DME services from facilities other than TACAN stations: ILS-DME or VOR-DME. Testing with the VOR-DME 108.6 (23X) in NTTR I get no DME info. Same with ILS-DME 25R MacCarran (40X).

 

As for the HUD INS range it is decluttering with landing gear down, not G/S capture. I don't now what the HUD should look like. Maybe they want to hide the range because the sources (INS, TACAN) wouldn't show 0 on threshold and don't want the pilot relying on them falsely. With the synthetic runway display, rad alt readout, markers, stopwatch they figured that was enough. No clue.

[jojo]

You won't get DME services out of Beslan with any airplane because there's no DME service there. The ILS is markers only for distance.

 

Mirage of course has DME transponder equipment. It appears to be permanent associated with the TACAN entry (not switching to frequencies paired to ILS entry at any time).

 

If you want to test if Mirage has robust systems modeling then one can try to use DME services from facilities other than TACAN stations: ILS-DME or VOR-DME. Testing with the VOR-DME 108.6 (23X) in NTTR I get no DME info. Same with ILS-DME 25R MacCarran (40X).

 

As for the HUD INS range it is decluttering with landing gear down, not G/S capture. I don't now what the HUD should look like. Maybe they want to hide the range because the sources (INS, TACAN) wouldn't show 0 on threshold and don't want the pilot relying on them falsely. With the synthetic runway display, rad alt readout, markers, stopwatch they figured that was enough. No clue.

 

Thanks for the NTTR report. Does DME work better with A-10C ?

[Frederf]

No A-10C DME on those VOR-DME or ILS-DME facilities either.

 

Also I suspect that in when only ILS is selected in EGI/HARS (no STPT, TCN) the range display should be flag covered and not display 000 miles.