In article , Robert Casey
writes:

Creative PLL and DDS subsystems of today, designed by others,
make it possible for anyone to select 10 Hz increments on any
HF band (30,000 frequencies within 300 KHz) with crystal-
controlled accuracy.

Analog VFOs are continuously variable. Making it possible for anyone
to select an *infinite* number of "increments" within a 300Hz
bandwidth much less your coarse 300 Khz wide example.

Sure, but those old VFOs tended to change the frequency a little
over time. AKA "drift".

Of course. That problem was insignificant in good-quality amateur gear by the
mid-late 1950s. Curing it was mostly a matter of getting away from bandswitched
self-controlled oscillators.

Most amateur HF operation does not require excellent long-term frequency
stability.

Me thinks one desires to select a frequency
and then have the rig stay put on it. Modern rigs can do that
to the accuracy and drift of a good crystal oscillator to some
set resolution. But for our uses, 10Hz resolution is more than
sufficient.

Exactly! But the designers have gone one better and commonly offer 1 Hz
resolution.

However, the original point was that such frequency synthesizers were somehow
"necessary" for hams. That is simply untrue.

And they do it
without generating any phase noise or other forms of crud synthesizers
toss out.

Kellie, define "phase noise" insofar as amateur radio operation is
concerned. You, for the limits of your technical knowledge, should
call that "incidental FM" which is what the industry term "phase
noise" refers. :-)

Then you should examine exactly how low that terrible phase noise
is. You can use the term "dbc" referring to the number of decibels
below the "carrier" (center frequency reference, not a modulated
carrier per se). The "crud" (as you term it) is quite far down in
relative power and certainly won't affect morse code reception of an
on-off keyed station's carrier.

The above reflects ignorance of the HF receiving environment commonly
encountered by hams, particularly those in DX, contest, and other competitive
situations.

Early 2 meter synthesized rigs had some trouble with this (the
phase noise would "add" to the FM modulation and produce extra
noise. Phase modulation and frequency modulation are closely
related, one is the integral (as in calculus) of the other.

Agreed.

As for HF CW, some poorly designed novice xtal oscillator
circuits probably had it worse than a modern synthesized rig.

Not at all.

And then there's chirp...

All curable with proper design.

73 de Jim, N2EY