wrote:

I just find it comical that throughout my avionics upgrade, many people
categorically gave the knee-jerk reaction to install a Garmin 430 or 530 and that the
KNS-80 was "obsolete junk." Apparently, if you don't fly behind a color, moving-map,
IFR-certified GPS, you're plane's barely capable of a sunday afternoon $100 hamburger.
It may be old, but is highly undervalued compared to replacing its functionality with
the de-facto units (e.g. KX-155 w/ GS costs about 2-3x, 430 costs 8-10x as much as a
KNS-80).

It isn't a knee-jerk reaction. Rho Theta calculations are marginal at best, and dangerous
at worst. The VOR system has lost a lot of accuracy since Rho Theta was the engineering
"rage" of the late 1970s.

If all you want is a $100 hamburger, get a hand-held GPS and fly VFR.