[time-nuts] Is 5061A by itself a primary reference? Was: Modern Rb atomic reference vs classic Cs

[Greg Maxwell]

On Sat, Mar 14, 2020 at 5:35 AM WB6BNQ <wb6bnq at cox.net> wrote:
> *By definition a Cesium frequency standard is just that, an absolute
> primary reference !  The only difference between the 5061A and another
> Cesium reference is a matter of degree of closeness to the absolute
> value.  For example the 5061A has a spec of +/- 1 in 10 to the -11th for
> accuracy, whereas, 30 later, the hp5071 has a spec of +/- 1 in 10 to the
> -12th.*

Because the 5061a does not automatically perform c-field adjustment by
itself and you cannot perform it without additional equipment (a
synthesizer), I wonder if it's pedantically correct to describe the
venerable 5061a _by itself_ as a primary reference?

The composite system of 5061+synthesizer+person-to-operate-it is a
primary reference.

Maybe my perspective on this is somewhat warped because I found
c-field adjustment on the 5061a to be a bit of a pain. :)

Perhaps this is all minutia,  but I also though it might be worth
reminding people that 5061a is not as plug-and-play as the 5071.