TACAN just isn't OK

Hi

I've been flying around in MP using various sources for TACAN to train interceptions with tankers and carrier ops.

I've noticed that tuning TACAN via Jester he tends to tune in the first frequency correctly, but seems to not update it when I order him to change to another.

So pressing the TACAN selector to me "PLT", I tune the new station but the it seems my radio doesn't tune anything. Switching back and forth doesn't work, and sometimes it just keeps the first frequency I asked Jester to tune, sometimes no TACAN is tuned, either via RIO or my panel.

Is this a known bug?

I have experienced what you are talking about, but what you have to remember is that TACAN is 'Line of Sight' (LOS). Meaning you have to be high enough for the antenna to "see" the TACAN station you dialed in. Just my two-cents to help you out, I have had no problems with TACAN lately on MP.

What I noticed in single player you ask him to change and it doesn’t show on the pilots Tacan but if you jump in the RIO’s seat it’s tuned correctly.

TACAN is working fine here as well.

Its not supposed to show on the pilots TACAN panel. Jester tunes his TACAN panel which is seperate from the pilots panel. The panel that is used to feed the HSD/_BDHI can be selected with the tacan cmd button

What I noticed in single player you ask him to change and it doesn’t show on the pilots Tacan but if you jump in the RIO’s seat it’s tuned correctly.

You mean the actual HSD, right? It wouldn't show on your knobs.

Well, even if Jester does tune the proper TACAN in the back, it's not showing any bearing or range on my HSI. Since I only fly MP, there's no way to know if Jester is doing his job.

If I tune the second TACAN on my own radio, though, I can't also get the new station. Either goes blank or just captures the previous tuned freq.

I can't be the only one with this. Just try it. Go to a MP server, tune a TACAN, say a tanker, then, tune another tanker or even a carrier, asking Jester to do it or doing it yourself. Unless all the servers I fly in are bugged, the Tomcat has an issue switching TACAN freqs.

I seem to have regular issues with Tacan in MP. Sometimes just doesn't work at all, and isn't even in the Jester menu to select. Putting it in manually as the pilot doesn't work either.

Hmm, I do not have any issues in MP. Only time it doesn't work is when I am not in range or do not have line of sight.

It's a DCS bug that TACANs intermittently stop working and come back later in MP. It has been around for a long long time and has nothing to do with the F-14.

Anyone has experience tacan lagging behind the C130 on Single player? at about 2NM tacan points about 10° left of where the AC is.

a bit of an unrelated question but on the HSD, the two diamonds represent the nose and tail of the aircraft but what is the house shaped symbol 90 degrees between the diamonds

Recovering this issue.

It now seems that TACAN erratic behavior is not a Tomcat exclusive issue. It seems to be happening on multiple aircraft too. I would say it looks like a DCS issue, not a module bug.

Sometimes it's there, sometimes it's not. Double and triple checking the freqs on Mission Editor, it just seems that the TACANs stop broadcasting randomly. Reason? Unknown.

The reason is that DCS units sometimes simply turn off their TACAN, this is a known issue. With switched condition triggers, time since flag and ai task set and flag off and on again this can be rectified however, and some servers simply do not do this.

As for the Tacan bearing showing about 10° off close to the tanker; this is due to the magnetic variation and is correct. The closer you get to the unit; the more apparent the magvar will become. It also depends on whether you fly a north south course or an east west course, as the magnetic deviation also depends on the earth curvature bending. all of this is simulated very accurately, and you will thus notice that on most east to west courses (which most missions use) the deviation will be bigger than on south north courses. Pitching will affect this additionally, again due to the earth's curvature. Another reason is that grumman did not connect the turn accelerometer to the AHRS amplifier, only the longitudinal accelerometer, which is also modeled correctly, to quote our dear Supergrover:

"Then, there's the magnetic flux valve (Magnetic Azimuth Detector - MAD) in the vertical tail. It's fixed. It feeds the AHRS with the relative direction of the magnetic North. When you roll or pitch, it becomes sensitive to the vertical component of Earth's magnetic field. This means - it becomes erroneous. That's why the directional gyro slaves to the MAD only in horizontal flight. At least in theory. In practice - you fly constant speed in a nose up attitude or with some hardly noticed bank for long enough, your directional gyro will slave to a slightly erroneous magnetic North.

That's why it's important to observe the HSD and the TID for the MV acronym (magnetic variation). It is displayed alternately with the IN or IM when the difference between the computed magnetic variation (MC) and the manual magnetic variation (VM) is greater than 5°.

If your directional gyro/synchro is shifted, it may result in erroneous interpretation of the TACAN direction on all instruments. You might have the tacan unit straight in front of your nose, but the BDHI will show the TACAN a few degrees to your left or right. However, the radial (bearing) reading would be correct; it would be just your magnetic heading wrong.

And there's much more... "

The reason is that DCS units sometimes simply turn off their TACAN, this is a known issue. With switched condition triggers, time since flag and ai task set and flag off and on again this can be rectified however, and some servers simply do not do this.

 

As for the Tacan bearing showing about 10° off close to the tanker; this is due to the magnetic variation and is correct. The closer you get to the unit; the more apparent the magvar will become. It also depends on whether you fly a north south course or an east west course, as the magnetic deviation also depends on the earth curvature bending. all of this is simulated very accurately, and you will thus notice that on most east to west courses (which most missions use) the deviation will be bigger than on south north courses. Pitching will affect this additionally, again due to the earth's curvature. Another reason is that grumman did not connect the turn accelerometer to the AHRS amplifier, only the longitudinal accelerometer, which is also modeled correctly, to quote our dear Supergrover:

 

"Then, there's the magnetic flux valve (Magnetic Azimuth Detector - MAD) in the vertical tail. It's fixed. It feeds the AHRS with the relative direction of the magnetic North. When you roll or pitch, it becomes sensitive to the vertical component of Earth's magnetic field. This means - it becomes erroneous. That's why the directional gyro slaves to the MAD only in horizontal flight. At least in theory. In practice - you fly constant speed in a nose up attitude or with some hardly noticed bank for long enough, your directional gyro will slave to a slightly erroneous magnetic North.

 

That's why it's important to observe the HSD and the TID for the MV acronym (magnetic variation). It is displayed alternately with the IN or IM when the difference between the computed magnetic variation (MC) and the manual magnetic variation (VM) is greater than 5°.

 

If your directional gyro/synchro is shifted, it may result in erroneous interpretation of the TACAN direction on all instruments. You might have the tacan unit straight in front of your nose, but the BDHI will show the TACAN a few degrees to your left or right. However, the radial (bearing) reading would be correct; it would be just your magnetic heading wrong.

 

And there's much more... "

Thank you Ironmike for this precious insight. I have two questions, if I may:

1- Can you (or would you) explain how to rectify the TACAN issue within ME. I mean, could you give me an example of a unit (say a carrier) and what I should do to prevent this? I can understand if you are reluctant to give these steps. This is a DCS issue, but there are no topics about this in this forum with proper support on this subject.

2- Is there a procedure to correct mag var in the Tomcat, then? Sorry but I come from civilian aviation where we're supposed to correct our gyro every 15 minutes using the wet compass as reference in my Cessna. Is this what you're supposed to do in the Tomcat too? Don't mind the joke, but that makes the F-14 a giant Cessna 172 :) . I thought these big jets had systems to correct this.

Thank you Ironmike for this precious insight. I have two questions, if I may:

 

1- Can you (or would you) explain how to rectify the TACAN issue within ME. I mean, could you give me an example of a unit (say a carrier) and what I should do to prevent this? I can understand if you are reluctant to give these steps. This is a DCS issue, but there are no topics about this in this forum with proper support on this subject.

 

2- Is there a procedure to correct mag var in the Tomcat, then? Sorry but I come from civilian aviation where we're supposed to correct our gyro every 15 minutes using the wet compass as reference in my Cessna. Is this what you're supposed to do in the Tomcat too? Don't mind the joke, but that makes the F-14 a giant Cessna 172 :) . I thought these big jets had systems to correct this.

It is fairly easy: so say we want to have the Stennis turn back its tacan every ten minutes:

First you need to click on the unit and then you get all the tabs like you would with aircraft, payload etc etc

The tab we want to go to is called triggered actions: it allows you to set advanced waypoint actions for the trigger actions AI TASK SET and AI TASK PUSH, in this case we want -> perform command -> activate tacan -> then set tacan frequency for example 74 and X and select the unit that is the stennis (ICLS btw is also affected so I recommend setting a second perform command triggered action to activate ICLS)

Nonetheless we want it also active at mission start, so on the spawn point of the Stennis, we just do the advanced waypoint option and set the same tacan and ICSL channel as in the triggered actions tab. (this is the one that will turn off after a while)

This is all we need to do with the unit itself.

Now we go to the triggers, and we want to setup 2 different triggers:

1. we set a trigger MISSION START - no condition - trigger action: Flag On (can use 1 for flag or any number you like, just note it down)

2. we set a trigger for SWITCHED CONDITION - condition: TIME SINCE FLAG, FLAG 1, 600 seconds - and now trigger action AI TASK PUSH: you will now be able to select from the drop down menu both activate Tacan and activate ICLS for the Stennis, so make 2 AI TASK PUSH actions, one for tacan, one for ICLS. Additionally: FLAG OFF (FLAG 1) and FLAG ON (FLAG 1)

And that is it; So every 10 minutes it will reactivate the tacan and ICLS, turn off the flag and turn the flag on again and then 10 min after the flag has been turned on again, due to switched condition trigger, it will do it again. Like that it will keep repeating every ten minutes for as long as you play the mission. :-)

For the magvar: you cannot correct the magvar as such (the earth dictates it), but you can correct the deviation of the AHRS by pressing the COMP button to the right of your right knee, hold it for about 1 minute, while flying straight and level at constant speed. The magvar will still exist though, as explained in my previous post above. (means you will still see the tacan carot point to either side depending on the magnetic variation)

Hope that was all clear and helps. :-)

It is fairly easy: so say we want to have the Stennis turn back its tacan every ten minutes:

 

First you need to click on the unit and then you get all the tabs like you would with aircraft, payload etc etc

 

The tab we want to go to is called triggered actions: it allows you to set advanced waypoint actions for the trigger actions AI TASK SET and AI TASK PUSH, in this case we want -> perform command -> activate tacan -> then set tacan frequency for example 74 and X and select the unit that is the stennis (ICLS btw is also affected so I recommend setting a second perform command triggered action to activate ICLS)

 

Nonetheless we want it also active at mission start, so on the spawn point of the Stennis, we just do the advanced waypoint option and set the same tacan and ICSL channel as in the triggered actions tab. (this is the one that will turn off after a while)

 

This is all we need to do with the unit itself.

 

Now we go to the triggers, and we want to setup 2 different triggers:

 

1. we set a trigger MISSION START - no condition - trigger action: Flag On (can use 1 for flag or any number you like, just note it down)

 

2. we set a trigger for SWITCHED CONDITION - condition: TIME SINCE FLAG, FLAG 1, 600 seconds - and now trigger action AI TASK PUSH: you will now be able to select from the drop down menu both activate Tacan and activate ICLS for the Stennis, so make 2 AI TASK PUSH actions, one for tacan, one for ICLS. Additionally: FLAG OFF (FLAG 1) and FLAG ON (FLAG 1)

 

 

And that is it; So every 10 minutes it will reactivate the tacan and ICLS, turn off the flag and turn the flag on again and then 10 min after the flag has been turned on again, due to switched condition trigger, it will do it again. Like that it will keep repeating every ten minutes for as long as you play the mission. :-)

 

 

For the magvar: you cannot correct the magvar as such (the earth dictates it), but you can correct the deviation of the AHRS by pressing the COMP button to the right of your right knee, hold it for about 1 minute, while flying straight and level at constant speed. The magvar will still exist though, as explained in my previous post above. (means you will still see the tacan carot point to either side depending on the magnetic variation)

 

Hope that was all clear and helps. :-)

Awesome help Ironmike. Thanks a bunch! :) You rock!