VOR Question, Direct-TO Indicators on HSI of a Dynon EFIS

[eetrojan]

Hi All, I train in a plane that has a Dynon EFIS-D100 fed by a Garmin SL30 NavCom. The EFIS includes an HSI consisting of a DG with a VOR overlay.

When I have a VOR tuned in, the Direct-TO indicator always shows the heading to fly directly to the station (the yellow diamond-tipped indicator below), or "reciprocally speaking," the radial from the station.

The Dynon manual shows a secondary or "standby" Direct-TO indicator (the orange colored circle-tipped indicator below), but I have never seen it.

If possible, I want to see two VORs at the same time to quickly triangulate my position in a "Lost-Diversion" exercise. So, I am trying to figure out if I can do that and, if so, how to also get the "standby" Direct-TO indicator to show up.

I tossed in a generic image of the Garmin SL30 for good measure.

Has anybody done this? If so, steps?

Thanks!

 

[gismo]

If I understand your question correctly I believe the answer is that this is not possible. IIRC, with a single SL-30 there's only one nav signal output even though the unit itself can monitor the "standby" frequency and display a bearing or radial for a second VOR. Now if you had two SL-30s (or one SL-30 plus a second VOR receiver of some other sort) I think your Dynon EHSI could show both pointers (BTW this is RMI functionality and the indications are generally referred to as "bearing pointers").

Also worth noting is that while some RMIs can show a bearing pointer to VORs in addition to NDBs (with suitable receivers attached) the processing of each is quite different. With a NDB, the bearing pointer follows a direct output from an ADF receiver (bearing is what an ADF delivers). But with a VOR signal, the bearing has to be computed from a combination of the VOR radial (what the VOR receiver decodes) and your heading. IOW if your heading is off, an ADF bearing pointer will still show the correct angle between the longitudinal axis of the airplane and the line to the transmitter but with VOR input, any error in heading will also show up in the relative bearing indication (and GPS bearings are a completely different animal from either VOR or NDB).

 

[eetrojan]

...with a single SL-30 there's only one nav signal output even though the unit itself can monitor the "standby" frequency and display a bearing or radial for a second VOR.

Thanks! I'll confirm this to the best of my abilitity, but I think you're right.