Terranav auto fixing even if radar is OFF?

I just have a question here. Isnt the terranav using the radar to know its location?

Howcome that even if I have the radar off the terranav still shows 5 on the datapad and updating the terranav system?

Do i really need to have the radar on for the terranav system to update?

The radar altimeter, yes.

The ground radar, no.

I think.

The radar altimeter, yes.

The ground radar, no.

I think.

You mean: I am sure. ;)

Only the radar altimeter is needed. Although currently turning of the RHM does not disable the TERNAV system. The RHM points downward, while the PS37 is located in the nose, really two completely different systems.

You mean: I am sure. ;)

 

Only the radar altimeter is needed. Although currently turning of the RHM does not disable the TERNAV system. The RHM points downward, while the PS37 is located in the nose, really two completely different systems.

So just to make sure I can also say "I am sure" - if you stick to barometric low altitude reading does the radar altimeter not emit?

I think it will have to emit for the TERNAV to work (barometric alt is useless for that) and also for altitude warnings to work. Should not be too hard to check.

I think it will have to emit for the TERNAV to work (barometric alt is useless for that) and also for altitude warnings to work. Should not be too hard to check.

Right no I understood that - what I am trying to figure out, is if I have the altimeter switched to Barometric, is the radar altimeter radar no longer emitting energy? I am trying to determine what needs to be done for an entirely passive flight.

If you want to go EMCON all the way, you can turn off the RHM (somewhere on the right panel in the neighborhood of the oxygen switch).

I tried to say that switching to barometric would probably not switch of the RHM, because:

1. It would also disable the height warning function. The latter should be based on RHM always as barometric altitude does not give height above ground in hills.

2. It would disable TERNAV and you would stop getting automatic NAV fixes.

Both are a pretty high price to pay for just wanting to see barometric altitude on the HUD. Therefore I concluded that RHM will remain on and thus transmitting. Using the RHM switch should do it though ...

If you want to go EMCON all the way, you can turn off the RHM (somewhere on the right panel in the neighborhood of the oxygen switch).

 

I tried to say that switching to barometric would probably not switch of the RHM, because:

1. It would also disable the height warning function. The latter should be based on RHM always as barometric altitude does not give height above ground in hills.

2. It would disable TERNAV and you would stop getting automatic NAV fixes.

Both are a pretty high price to pay for just wanting to see barometric altitude on the HUD. Therefore I concluded that RHM will remain on and thus transmitting. Using the RHM switch should do it though ...

We're on the same page then, I only wondered because I do think about emissions and detection by ground sensors - though this is probably poorly if at all modeled in DCS and thus irrelevant to "play" - if you were doing some real deep strike stuff IRL such considerations would probably matter but especially here it IS a major price to pay if the only simulated result is not having radar ranged altitude on the HUD.