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Use Tacan DME combined with ADF ?


Ryuk99

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Hi,

 

is it possible to use the ADF to find the direction to the VOR station and at the same time the TACAN for the DME so we can get distance? That would be great to effectively use VOR/DME stations

 

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Sure, but you are missing the nuance

ADF operates in the 200 - 1700 ish Khz range (give or take , i forget the exact numbers)

VOR operates in the 110 - 117 ish Mhz range (give or take)

Hmmm, how am i receiving signals from VOR stations ingame then? Thats weird

 

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.... what's more, the information is not sent in the same format. The hardware uses different logic to make sense of the different signals. Im sure the tech exists

now to create equipment capable of handling both, but ADF is practically out dated now so the motivation to do so is probably lacking. And back when ADF was ubiquitous the technology to shoe horn ADF and VOR receiver's in the same "box" i dont think exist. Educated guess.


Edited by Lex Talionis

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.... what's more, the information is not sent in the same format. The hardware uses different logic to make sense of the different signals. Im sure the tech exists

now to create equipment capableto handle both, but ADF is practically out dated now so the motivation to do so is probably lacking. And back when ADF was ubiquitous the technology to shoe horn ADF and VOR receiver's in the same "box" didn't exist.

Okay, thanks for the extra infos

 

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Hi,

 

is it possible to use the ADF to find the direction to the VOR station and at the same time the TACAN for the DME so we can get distance? That would be great to effectively use VOR/DME stations

 

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Yes, absolutely. DMEs are simply TACAN facilities that only provide the range service and not the azimuth service. Because TACAN and communication radio ADF are independent they can be used simultaneously.

 

You tune the communication radio to the VOR and enable the ADF function and tune TACAN to the DME channel. If the DME and VOR are co-located you've made a poor man's TACAN. In reality the azimuth stability and accuracy would be inferior to a true TACAN but apart from that it would be the same kinda thing.

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Yes, absolutely. DMEs are simply TACAN facilities that only provide the range service and not the azimuth service. Because TACAN and communication radio ADF are independent they can be used simultaneously.

 

You tune the communication radio to the VOR and enable the ADF function and tune TACAN to the DME channel. If the DME and VOR are co-located you've made a poor man's TACAN. In reality the azimuth stability and accuracy would be inferior to a true TACAN but apart from that it would be the same kinda thing.

 

But how do i tune in into the DME with Tacan? I mean it uses a Frequency (like 116.65 mhz) and not a Channel (like 84Y)

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That's the thing about the number-x/y channels, they're actually bundles of frequency definitions for several different radio navigation services. When you say "channel _" you're not just saying a single frequency. You're really relying on the context of which particular instrument which part or parts of the channel definition you're interested in.

 

In this case that's 113Y because that's:

VOR 116.65 MHz

MLS angle 5086.8 MHz

DME 1137 & 1076 MHz

 

Channel 42X is...

ILS LOC 110.5 MHz

ILS GP 329.6 MHz

MLS angle 5038.2 MHz

DME 1066 & 1003 MHz

 

So a USAF fighter plane can be on 42X TACAN while a Cessna 172 is using 42X ILS and the Space Shuttle is landing on 42X microwave landing system (MLS). They're all on 42X but none of them are using the same frequency.

 

There is really nothing stopping Cessna avionic manufacturers from labeling all of their VOR, ILS, DME, etc. frequencies in channel numbers. You enter "108.00" into the VOR but you might as well enter 17X. It's the same thing. It's just a convention that the military uses the channels by name and non-military uses the raw frequency.

 

In fact if you tune a VOR-DME in a Cessna the DME part won't use the frequency you enter. E.g. if you tune VOR-DME 109.60, the DME radio in the airplane knows to actually tune DME 1057 MHz because it knows to associate that DME frequency with that VOR frequency. Even if it's just a DME station with no VOR often you can tune in the VOR frequency (which won't work) to force the DME to tune in the frequency of that same channel. The Cessna DME radio I used would let you pick between automatic matching VOR1 or VOR2, or manually set. Manual DME was rarely used but in theory you could. In just the same way when you tune an ILS localizer the glideslope radio automatically tunes the associated glideslope frequency (which is about 3x higher).

 

https://www.tele.soumu.go.jp/resource/e/search/share/pdf/a2-2.pdf

 

Using the linked PDF channel-frequency table. You tell me what TACAN channel to tune if you want distance readout to VOR-DME 113.30 MHz.

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VOR and TACAN use the same DME system, so in theory it should work fine so long as you convert the VOR freq to the proper channel. You can see a list of all channel frequencies starting on page 8 here: https://www.ntia.doc.gov/legacy/osmhome/redbook/4d.pdf

 

I've never tried to ADF a VOR before, that just seems silly, but I expect it should work?

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Just a heads up, ADF does not only equal NDB anymore. It depends on the planes ADF (Automatic direction Finding) system. As someone said earlier,

So i looked up the natops flight manual of the f/a 18 and it says the OA-8697/ARD ADF is a VHF/UHF direction finder operating from 100 to 400 MHz
. At the end of the day, as far as an AFD cares, they are just radio frequencies. You can tune into pretty much any navaid station that is designated between 100 to 400 MHz, and yes, that includes VOR, ATC, VHF, and UHF stations ;). But remember, the only thing that the ADF is going to do is point to the source of the emitter.
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That's the thing about the number-x/y channels, they're actually bundles of frequency definitions for several different radio navigation services. When you say "channel _" you're not just saying a single frequency. You're really relying on the context of which particular instrument which part or parts of the channel definition you're interested in.

 

In this case that's 113Y because that's:

VOR 116.65 MHz

MLS angle 5086.8 MHz

DME 1137 & 1076 MHz

 

Channel 42X is...

ILS LOC 110.5 MHz

ILS GP 329.6 MHz

MLS angle 5038.2 MHz

DME 1066 & 1003 MHz

 

So a USAF fighter plane can be on 42X TACAN while a Cessna 172 is using 42X ILS and the Space Shuttle is landing on 42X microwave landing system (MLS). They're all on 42X but none of them are using the same frequency.

 

There is really nothing stopping Cessna avionic manufacturers from labeling all of their VOR, ILS, DME, etc. frequencies in channel numbers. You enter "108.00" into the VOR but you might as well enter 17X. It's the same thing. It's just a convention that the military uses the channels by name and non-military uses the raw frequency.

 

In fact if you tune a VOR-DME in a Cessna the DME part won't use the frequency you enter. E.g. if you tune VOR-DME 109.60, the DME radio in the airplane knows to actually tune DME 1057 MHz because it knows to associate that DME frequency with that VOR frequency. Even if it's just a DME station with no VOR often you can tune in the VOR frequency (which won't work) to force the DME to tune in the frequency of that same channel. The Cessna DME radio I used would let you pick between automatic matching VOR1 or VOR2, or manually set. Manual DME was rarely used but in theory you could. In just the same way when you tune an ILS localizer the glideslope radio automatically tunes the associated glideslope frequency (which is about 3x higher).

 

https://www.tele.soumu.go.jp/resource/e/search/share/pdf/a2-2.pdf

 

Using the linked PDF channel-frequency table. You tell me what TACAN channel to tune if you want distance readout to VOR-DME 113.30 MHz.

That would be 80X. So i just tried it out with a VOR/DME station, ADF tuning into 114.60 mhz, working great, TACAN tuning into 93X and its not working, its just circling in the HSI searching for a signal i guess. What am i doing wrong here?

 

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That would be 80X. So i just tried it out with a VOR/DME station, ADF tuning into 114.60 mhz, working great, TACAN tuning into 93X and its not working, its just circling in the HSI searching for a signal i guess. What am i doing wrong here?

 

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It should hunt for azimuth because there's no azimuth TACAN service on a VOR-DME. What should happen is you get only distance the same as air to air "yard stick."

 

Either there is some aspect of the F-18's TACAN hardware which is inhibiting DME readout if azimuth service is unavailable or DCS World programmers didn't include the ability for non-TACAN DME facilities to provide ranging to TACAN receivers even though that is a real capability. My guess is the second one.

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