Bill Turner ) writes:

Also, a GDO is likely to be much less expensive
than the three separate items.


Bill, W6WRT

That's always been some of its appeal. Throw one together, or buy one,
and you get a tool for finding the rough frequency of a coil. But you
also get that ability to figure out an unknown L or C, you get a signal
generator, you get a wavemeter (which also still has potential use),
you get a general purpose oscillator that you can connect a crystal to,
and you get likely some other uses that don't immediately come to mind.

They date from a time, late forties is when they started becoming popular
but I'm uncertain if the concept was there before, when the average ham
had little test equipment, and even labs and repair places might not
have all that much of it. It was a handy little unit, relatively easy
to build, that did give good returns.

Of course, a lot of recent equipment isn't conducive to as easy use
with a GDO, with self-shielding toroids and the rest shielded in cans.
Construction isn't nearly as wide open as in the days of tubes.

But whether it's worth having likely depends on a mindset. If someone
wants to load down on tons of test equipment, then a GDO is likely
redundant. But a GDO can have its uses, especially if one doesn't have
a wide-range signal generator.

Michael VE2BVW