Hi HighVoltage,
All your 4 instruments confirm the very good stability of the SVR-T, essentially the same magnitude as with my 3458A.
All these references, especially the LTZ, are very sensitive to AF noise, especially from switch mode PSUs.
So in my basement, where my analogue lab is situated, there are conventional lamps (50Hz) only, no WLAN, no cellular phones and no DECT station.
The steel wires in the concrete roof also filters most of radiation from outside.
(FM radio can be received, through a small window, anyhow.)
So, a (good German) basement gives a near perfect shielded lab.
A pity, that in many areas of northern Germany , you don't have basements in the houses.
(My brother in law doesn't have one, either, he's living in the
Oldenburger Münsterland, where they have moorland. So he use to bury many of his tools in his 1/2 hectare garden..
)
PS: When will you have the opportunity to compare the SVR-T etc to a DKD lab?
Frank