[time-nuts] CS frequency standard

[John Miles]

> Few people need the CS on all the time. The other funny thing on the HP
> series you can turn the tube off and just use the OCXO after its been
> adjusted accurately.
> I run my HP 5065a Rb the same way. Power as needed and every 6 months.
> So you are very lucky to have a good CS.

Rbs are a bit different in that they need time to stabilize.  Shortly after you turn on a Cs standard it is as stable as it will ever be, but a 5065A or other Rb will often need at least a couple of days to achieve its best stability.  So I leave my 5065As on all the time but I only run Cs standards when needed.  They are left plugged in to keep the tube pumped down with the beam current shut off.   I had to modify my 5062C to allow that by adding an extra switch, and IMHO you should do the same thing with the 4060 if it doesn't already have a standby mode.  

You don't have to power up the whole thing periodically as long as the ion pump is left running 24/7.  I've seen a couple of cases where the tube has failed due to an open hot-wire ionizer filament so I prefer not to turn mine on all the way except when they're needed, or as a (very) occasional check.

-- john, KE5FX
Miles Design LLC