Michael wrote:

wrote
I would prefer to have one of those boxes (I forget what they're called
- they're from before my time 8^) ) that creates virtual waypoints using
VORs and DME. I would think that would be the ideal alternative to GPS,
seeing as the VOR/DME signals are less susceptible to environmentally
caused signal degradation.

They're caller rho-theta RNAV (also VOR-DME RNAV). The KNS-80 was
probably the most popular, and it works well, but there are quirks.
Most importantly, it won't usbstitute for the underlying navaid on an
approach, the way GPS and LORAN will - get low and you lose the VOR
and/or DME signal.

[...]

They can't. Actually, I use LORAN all the time. IMO the hot setup is
LORAN and GPS in separate boxes with separate power sources.

I like the idea of two separate units[1], but why not have both be "combo"
units like (I think) one you mentioned earlier on this thread. In fact,
why not have that "combo" unit also exploit VOR/DME input? There's really
no reason why the current GPS UIs couldn't be put on a box that uses any
(reasonably accurate {8^) means of navigation.

The fact that some signals disappear under certain conditions (satellite
view, sunspots, descending below VOR coverage, etc.) must become part of
the procedure for using the box...but this is already the case, just on
separate devices.

Ultimately, I hope, adding a new navigation sensor (ie. GA-cheap inertial
navigation {8^) will make no real difference in the procedures through
which we use our navigation devices.

- Andrew

[1] I just flew a GPS approach today that had a GPS-only
missed. As I fly with only a single IFR-certified GPS,
these make me somewhat uncomfortable.