Was idly surfing the net looking for some more toys to put into my panel, when I came across this
TCAS unit
I'm really in two minds about the usefulness of this device.
There is no bearing information for the threats it detects. There are no TCAS resolution advisories. If you suddenly spot an aircraft during a traffic alert, there's no guarantee that it's the one the unit is warning you about.
On the other hand, a traffic warning would certainly concentrate your mind on the lookout, and may lead you to spot something sooner than you would otherwise.
So would you go buy one?