DME Hold

[winsth]

Good evening Peter and all other coders/simmers,

I'm looking for a way to enable "DME HOLD" i.e. to keep the DME indications from a VOR/LLZ and still be able to tune in another VOR/LLZ. (Ask me and I'll explain in more detail, but I guess you know how it works)

DME HOLD is a function that almost 100% of all aircraft (larger than a C172) has today.

I want to keep using both NAV1 and NAV2 so using a "hidden" NAV2 for DME only is not an option. A third NAV in FS would solve my problem.. ;)

So...

...is there any way at all to read the distance to a third VOR?

...has anyone seen this function in a FlightSim addon or panel? I haven't tried Project Magenta. Do their addons have this feature?

I'm very grateful for any hints or leads! Please don't hesitate to post a reply if you know that this won't work (so I can give up :) ).

Have a great night and thanks in advance!

/ Magnus Winsth

[Pete Dowson]

...is there any way at all to read the distance to a third VOR?

No. FS has its DMEs tied exclusively to its NAV radios. There's no way possible unless you invent your own DME program with a complete database of VOR/DME stations.

Regards,

Pete

[winsth]

Thank you for your reply, Pete!

Ok... I guess one way would be to read(and store) the long,lat and elevation of the DME station (VOR) and triangulate the distance between those values and the aircraft position.

This works in theory (right?) but has anyone tried this in FS?

G'night!

/ Magnus

[Pete Dowson]

Ok... I guess one way would be to read(and store) the long,lat and elevation of the DME station (VOR) and triangulate the distance between those values and the aircraft position.

Yes, that is what I meant by using a database of stations.

If you didn't mind tuning into the VOR on an FS NAV radio first, then click a button or something to tell your program "this is the DME" (assuming it is a VOR-DME) then you could have that program carrying on giving you DME info for that station even after you re-tuned FS's NAV radio.

There is certainly enough information available from FSUIPC for all this, and the "triangulation" problem is pretty simple trig if you assume you are close enough to the station to use planar geometry rather than spherical.

This way you wouldn't need your own VOR database.

Regards,

Pete

[dfournie]

I got this to work earlier in the year. Using the DAFIF nav database and identifying stations that had co-located VOR/DMEs I was able to get my system to perform routine DME holds. Great for shooting DME arcs. This week I started to get TACAN to work the same way. By consulting the DAFIF nav database and looking for TACAN stations, I'm able to use the data available from VORTACs, and where the TACAN station is not co-located with a VOR, to simulate the station being there through a simple triangulation routine.

[winsth]

Hi again,

Sounds great! I think I will begin with the "simple" method without a database. I will read and store the position of the active DME station in a couple of variables when DME HOLD is switched on.

Have a great day!

/ Magnus