+x

 

cloudless - 8/22/2022 9:58:46 AM

Hi everyone,

new SkyDemon user here.

I'm a bit confused because the way I learned VORs is that they are referenced to magnetic north. At least to a certain amount, as they are not updated every time the variation changes.

But it seems SkyDemon defaults to referencing them to something else? For example, see the KRH VOR in south-west germany:

On the right side is an ICAO chart pulled from DFS AIS with the 360° radial in red and the SkyDemon one copied from the left picture in black.

The one from skydemon

a.) doesn't match with the one provided by the DFS

b.) isn't directly 360° true north either, it seems more like 355° or something

c.) the difference between them could be the variation (something link 2-3° here)

So is the data of the VOR wrong?

I had expected SkyDemon to provide, display and reference radials of VORs according to "magnetic". In parenthesis because, as noted above, their might be a slight discrepancy by the VORs not always updating their reference with every variation change.

Thanks for the clarification,

cloudless

+x

 

cloudless - 8/22/2022 8:08:23 PM

Is this a real question? Of course it matters: the orientation of the VOR rose is the visual representation of the north reference.

So if I pull up my ICAO chart and read a course of radial 45° magnetic outbound it seems to be a legit questions why the radial 45° of the same VOR in SkyDemon has an offset to the one provided in the official chart - or am I missing something?

In fact, the orientation of the VOR rose is the only way to get the real radial from a VOR (besides pulling up the data of the variation used by the VOR in some database).

EDIT:

So I re-checked/measured with the help of the SkyDemon map ruler and it seems that the VORs are oriented according to true north and point b.) in my listing was wrong.

The difference of the radial to the one provided by the official DFS map source could be indeed attributed to the variation in the area. Since VORs are oriented to magnetic north (to a certain degree) rather than true north, I would still prefer to have them oriented that way. I don't know about elsewhere but at least in switzerland and germany it is common for them to be displayed that way.

I mean just think about what happens if you fly in an area of 90° E variation (and say the VOR is updated to this variation) but your SkyDemon VOR north reference still points to true north:

- If you fly, say, radial 180 outbound of the VOR (the real one) you would fly a true course of 270°

- Now you want that radial on your SkyDemon map. You "Track Radial" and input 180° (as this is the value you turned your OBS in the cockpit to). But as far as I can see it, SkyDemon takes that as a true north value. So in your SkyDemon map you would get an actual southbound course whereas the course you actually fly is a westward one.