A10C TACAN Problem

[Barrettone]

I'm having an issue with the TACAN on both A10C & A10C II - very simple, I turn the TACAN on, with TCN selected below the HSI, the correct station selected, powered to T/R for landing or A/A T/R for tankers, and in multiplayer, mission or training I get no response - no noise despite adjusting volume, no range, no bearing, nothing. I feel like I'm missing something obvious but I can't see it. 

Any advice? 

[Jascha]

What's the range to your selected TACAN station? Is it within line of sight?

[Barrettone]

Various, but in the case of tankers, within line of sight and <50nm. 

In the latest failed effort, 8nm to Batumi

[Jascha]

I just checked Instant Action - Free Flight for A-10C (Caucasus). After gaining some altitude I picked up Batumi (16X) and Kobuleti (67X) from ~80nm with no problems (heading and range). I suggest you check this default mission as well.

As for the volume - did you unmute TCN switch on the intercom radio panel (with RMB)? It must be up.

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Edited June 25, 2022 by Jascha

[Barrettone]

Ah, I was rotating that but didn't realise it had to be popped out , that seems to have solved the problem. Thanks.

[jaylw314]

For reference, both the ILS and TCN knobs on the audio panel default in the down/off position.  All the others start out up/on.

Doesn't explain why you weren't getting range/bearing.  If you were receiving the TCN signal, you'd be getting range/bearing regardless of whether the audio knob is on or off, so there was probably some other step that was missed...

Also, FWIW, in DCS, tankers use T/R mode, not AA T/R.

Edited June 25, 2022 by jaylw314

[Jascha]

1 hour ago, jaylw314 said:

Also, FWIW, in DCS, tankers use T/R mode, not AA T/R.

That's correct. Although from my experience - if tanker is on TACAN channel Y, AA T/R works... but only partially (provides bearing but no range). Has this been officially reported?

[jaylw314]

2 hours ago, Jascha said:

That's correct. Although from my experience - if tanker is on TACAN channel Y, AA T/R works... but only partially (provides bearing but no range). Has this been officially reported?

Yes, I can't recall where, but ED stated that was their intention.  The why is controversial and unclear

[Jascha]

8 hours ago, jaylw314 said:

Yes, I can't recall where, but ED stated that was their intention.  The why is controversial and unclear

Meaning that it is correct as is?

I guess, it should be rather easy to verify with people who used/use this IRL.

[ASAP]

From everything I’ve ever read/heard, IRL the tanker would have a tacan code (x or y doesn’t really matter whatever is assigned) and the receivers would set their tacan 63 out from that and matching the x or y (ie. if tanker has 6Y receivers have 69Y set). The tacan should be set to AA T/R and the fighters would get range only to the tanker, no bearing. 

[Jascha]

31 minutes ago, ASAP said:

The tacan should be set to AA T/R and the fighters would get range only to the tanker, no bearing. 

You mean bearing only (no range), right?

[Yurgon]

4 hours ago, Jascha said:

You mean bearing only (no range), right?

No, I'm pretty sure it's range only.

The KC-10 and the KC-46 can do bearing. The KC-135 (and the KC-130 and the S-3, when we look at probe and drogue in DCS) can't, that's range only. So what ASAP describes is the same kind of TACAN that aircraft in a flight can use among one another: TACAN yardstick, giving range information only.

In DCS, the KC-135 does give bearing information, but if we want to do it realistically, mission designers should deactivate the bearing information for these tanker aircraft.

[ASAP]

6 hours ago, Jascha said:

You mean bearing only (no range), right?

nope. All you get is range. DCS has it backwards.

[Frederf]

4 hours ago, Yurgon said:

mission designers should deactivate the bearing information for these tanker aircraft.

I have never had the "bearing" checkbox in the editor ever have an effect. With unchecked I got bearing. With checked I got bearing. (this is in the old times when tanker TCN was A/A mode).

[jaylw314]

10 hours ago, Jascha said:

Meaning that it is correct as is?

I guess, it should be rather easy to verify with people who used/use this IRL.

"Correct" is a relative term  .  Maybe it's best left "as intended."

FWIW, range-only TACAN would be tough to use for rendezvous when you have dumb AI tankers.  AFAIK, IRL the tanker would help you out in a variety of ways (hitting waypoints on time, communications, etc.), all of which the AI tankers are incapable of doing.

Bearing is actually trickier because you need some kind of directional antenna to broadcast bearing info.  Range is pretty easy and just requires to radios "handshake" a signal--one airplane signals the other, the other signals back, and the first airplane times how long it takes to determine slant range.  That takes a minimum of equipment and a tiny antenna.

[ASAP]

8 minutes ago, jaylw314 said:

"Correct" is a relative term  .  Maybe it's best left "as intended."

FWIW, range-only TACAN would be tough to use for rendezvous when you have dumb AI tankers.  AFAIK, IRL the tanker would help you out in a variety of ways (hitting waypoints on time, communications, etc.), all of which the AI tankers are incapable of doing.

Bearing is actually trickier because you need some kind of directional antenna to broadcast bearing info.  Range is pretty easy and just requires to radios "handshake" a signal--one airplane signals the other, the other signals back, and the first airplane times how long it takes to determine slant range.  That takes a minimum of equipment and a tiny antenna.

Real life there are air refueling rendezvous points, control points, set rendezvous times and talk ons both from radar controllers and tanker position callouts like you said. Probably easier for DCS to sprinkle some magic dust on the whole thing and just give us a tacan bearing. Doing it the right way requires a lot of mission planning, understanding of procedures,(and a smart tanker crew like you said). I can’t really fault DCS for taking the easier option here.

[Yurgon]

33 minutes ago, Frederf said:

I have never had the "bearing" checkbox in the editor ever have an effect. With unchecked I got bearing. With checked I got bearing. (this is in the old times when tanker TCN was A/A mode).

Oh my, I never knew this, but you're right, that's still how it works.

I filed a bug report.

[Jascha]

5 hours ago, Yurgon said:

No, I'm pretty sure it's range only.

The KC-10 and the KC-46 can do bearing. The KC-135 (and the KC-130 and the S-3, when we look at probe and drogue in DCS) can't, that's range only. So what ASAP describes is the same kind of TACAN that aircraft in a flight can use among one another: TACAN yardstick, giving range information only.

In DCS, the KC-135 does give bearing information, but if we want to do it realistically, mission designers should deactivate the bearing information for these tanker aircraft.

Ok, but how about using regular T/R mode instead of AA T/R to make it work with tankers? Is this how it should be?

And does TACAN channel X/Y should matter? Because in DCS apparently it does (tanker on channel X results in AA T/R not working, channel Y - bearing only, no range). At least that's my experience with A-10C. I'm not sure if the TACAN channel number is relevant too.

[Yurgon]

1 hour ago, Jascha said:

Ok, but how about using regular T/R mode instead of AA T/R to make it work with tankers? Is this how it should be?

For range only, it should be AA T/R. With DCS, it's changed so much over the years and between the versions, I'm not even sure any more what works these days. I just keep trying T/R and AA T/R and Y or X until it works. If it all fails, then it's probably not working as intended, which was the case a couple of versions ago.

1 hour ago, Jascha said:

And does TACAN channel X/Y should matter?

Yes it should, but a few versions ago, it was inverted.

Generally, I believe ground based stations are usually using X while air based stations use Y, or at least that's what I've gathered, but I'm not 100 % certain that this is really how it works IRL. And again, in DCS it works one way this month and another way next month, hard to keep track.

[Frederf]

Most folks say no. ED are investigating last I hear.

The reason for X/Y mattering is frequencies. Ground X and Air X use different frequencies. Ground Y and Air Y use the same frequencies. This is why setting 1X A/A in your airplane when tanker is broadcasting ground 1X it doesn't work. However when you set 1Y A/A in your airplane and tanker is broadcasting ground 1Y it does. I don't think in real life 1Y ground and 1Y A/A are supposed to crosstalk despite using the same frequencies, but that's the DCS logic.

• 1X Ground, Interrogate, 1025 MHz (12µs), Reply 962 MHz (12µs)
• 1Y Ground, Interrogate, 1025 MHz (36µs), Reply 1088 MHz (30µs)
• 1X Airborne, Transpond, 1025 MHz (12µs), Receive 1088 MHz (12µs)
• 1Y Airborne, Transpond, 1025 MHz (36µs), Receive 1088 MHz (36µs)

You can see that 1XG and 1XA don't even match up frequencies for sending and receiving while 1YG and 1YA do. 1YG and 1YA should filter each other out based on signal characteristics (single/double pulse, pulse spacing) but they don't in DCS.

[ASAP]

Simple answer is the x or y makes a difference. 6X only pairs with 69X not 69Y, 6Y only pairs with 69Y and not 69X. It’s easiest to think of them as completely different frequencies. Generally ground stations will be X and air to air tacans will be Y but I don’t think that’s a hard and fast rule

 

Edited June 26, 2022 by ASAP