Maximum TACAN distance ?

[Top Jockey]

Hello,

I went very far from the Carrier, and at the F-14's HSI monitor I keep getting the TACAN direction needles / arrows and the range digits to the Carrier keeps updating also.

... I've managed to go 620 nm from the Carrier and the TACAN info kept updating.

 

- Caucasus Map

- F-14A

- CVN-74 (no Supercarrier)

Can a Carrier TACAN signal get that far IRL ?

Wasn't it supposed for the needles and the range digits to disappear after one gets too far away ?

 

[draconus]

Quote

Operating range is approximately 300 NM, if line of sight is given.

https://www.heatblur.se/F-14Manual/general.html#tacan-system-an-arn-84

 

Wiki says:

Quote

TACAN stations can provide distance up to 390 nautical miles.

Edited October 13, 2023 by draconus

[Top Jockey]

24 minutes ago, draconus said:

https://www.heatblur.se/F-14Manual/general.html#tacan-system-an-arn-84

 

Yeah, I had the far recolection that it could be around 350 or even less.

 

So, assuming that when out of range from the Carrier TACAN, the info on the HSI (needles and range), as well as the deviation bar at the VDI and HUD should disappear - just like when entering the wrong TACAN channel ?

This is probably a bug, as I've managed to get TACAN signal from ranges of more than 950+ nm.

 

 

Edited October 13, 2023 by Top Jockey

[QuiGon]

6 minutes ago, Top Jockey said:

 

Yeah, I had the far recolection that it could be around 350 or even less.

 

So, assuming that when out of range from the Carrier the info on the HSI (needles and range), as well as the deviation bar at the VDI and HUD should disappear, this is probably a bug, as I've managed to get TACAN signal from even 950+ nm.

 

Have you tried that with other aircraft too?

[Top Jockey]

1 minute ago, QuiGon said:

Have you tried that with other aircraft too?

 

Not yet.

[QuiGon]

Just now, Top Jockey said:

Not yet.

Would be interesting to know if it's a general DCS issue or a Tomcat specific issue. I might test that myself when I find the time to do so as I'm curious now.

[Top Jockey]

2 hours ago, QuiGon said:

Would be interesting to know if it's a general DCS issue or a Tomcat specific issue. I might test that myself when I find the time to do so as I'm curious now.

 

I've been testing with the Hornet in roughly the same circumstances as the Tomcat, and the 'behavior' seems more plausible.

... although with some doubts from my part, as I do not have the slightest idea as how it really works in IRL.

 

- flying at 40.000 ft or above, it appears to get a solid TACAN reference at distances from 430 ~ 450 nm and below

- at those distances, it can sometimes get alternate random range readings of many different values, as if it is having difficulty in receiving a good, steady TACAN signal

- near 390 nm distance and below it gets definitely steady

 

On the other hand, it can also receive the Carrier TACAN signal at distances as far as 900+ nm ...

- even if for only a very small time fraction

- it does give correct distance (range) of 880.9 nm from Carrier - as in screenshot below, bearing marker, TKR Carrier code

- sometimes an " S " blinks instead of the TKR code

- after those very brief moments, the bearing marker may be lost or not, and the range readings get alternate random values again.

 

Concluding:

Is it realistic that even for very brief moments, (in good weather, high altitude) the Hornet could capture a Carrier TACAN signal from that far away ?

 

 

 

Edited October 13, 2023 by Top Jockey

[draconus]

The LOS horizon is 213nm at 40k ft alt but the VHF can propagate much longer due to the atmosphere effects/scatter. As for the signal that strong, I doubt it.

[Top Jockey]

22 minutes ago, draconus said:

The LOS horizon is 213nm at 40k ft alt but the VHF can propagate much longer due to the atmosphere effects/scatter. As for the signal that strong, I doubt it.

 

Ok, so should this issue be a bug report or what ?

[draconus]

17 minutes ago, Top Jockey said:

Ok, so should this issue be a bug report or what ?

@BIGNEWY What do you think? General DCS issue?

[IronMike]

Looks like a DCS issue, I remember not receiving TACAN in the F-14 until in range before.

[Top Jockey]

10 minutes ago, IronMike said:

Looks like a DCS issue, I remember not receiving TACAN in the F-14 until in range before.

 

So might it be (in my case) related to be currently using a Open Beta version ?

[draconus]

Idk, I also tested F-15E and got signal degradation around 360nm and max around 400nm from CVN-74 TACAN. Much shorter to ground station (140-170nm) but it could be some LOS issue.

F-14 otoh has no limits to TACAN either with CVN-74, S-3 (Caucasus) or ground station (PG) - I stopped testing over 500nm.

@latest beta

F-14 PG GND TACAN.trk F-14 S-3 TACAN.trk F-14 CVN-74 TACAN.trk

[Top Jockey]

2 hours ago, draconus said:

Idk, I also tested F-15E and got signal degradation around 360nm and max around 400nm from CVN-74 TACAN. Much shorter to ground station (140-170nm) but it could be some LOS issue.

F-14 otoh has no limits to TACAN either with CVN-74, S-3 (Caucasus) or ground station (PG) - I stopped testing over 500nm.

@latest beta

F-14 PG GND TACAN.trk 109.91 kB · 0 downloads F-14 S-3 TACAN.trk 73.25 kB · 0 downloads F-14 CVN-74 TACAN.trk 208.6 kB · 0 downloads

 

Thank you @draconus

Those are my conclusions also, even tried on typical quickstart not much edited / not very old (past open beta versions) missions.

 

If, in most cases the F-14 can get the Carrier's TACAN signal until near ~ 560 nm or so, on other missions for resons I don't know it can get the Carrier's TACAN signal from more than 960 nm.

 

I suppose ED or Heatblur could look at this.

[Victory205]

The rule of thumb is (1.22 * sqrt of the delta height in feet). This returns the distance in miles, either divide to convert distance to NM or use 1.06 as the coefficient in the formula.

Is the curvature of the earth modeled, or is it “flat” in DCS? The TACAN emitter is located on the mast on the carrier, at least 200 feet above the water as well. Guessing that isn’t modeled either. I’ve not checked to see if TACAN is masked by terrain either. TACAN operates on frequencies limited to line of sight. 

Edited October 15, 2023 by Victory205

[draconus]

12 hours ago, Victory205 said:

Is the curvature of the earth modeled, or is it “flat” in DCS? The TACAN emitter is located on the mast on the carrier, at least 200 feet above the water as well. Guessing that isn’t modeled either. I’ve not checked to see if TACAN is masked by terrain either.

The curvature is modeled for radars, for radios - idk. LOS is modeled for both.

[bonesvf103]

The huge indicated range to TACAN in the Hornet was a known bug, but I haven't experienced it lately.  What wyou did was you tuned the TACAN and you got some ridiculous range from it, then you turn off the TACAN and turn it back on  and the range was then correct.

@Victory205:  I do think terrain masks TACAN.  I've experienced it in the NNTR map for one--ducking behind a mountain and I'd lose the TACAN and it would come back when I crested it.  It think I saw it happen in the other maps too.

v6,

boNes