[time-nuts] how long dues this rubidium standard last for

[cdelect at juno.com]

Paul,

I agree with Bob, the small telecom ones to include the Efratom ones have
a lifetime that is just a guess at this point.

A brand new PRS10 with a warranty and the original owner repair discount
would be a good bet, they do however have lamp assy problems unless that
has been redesigned.

The HP5065A however has no significant failure modes, and I have worked
on and seen good performance out of 40 Year old units!

As discussed here before 5065A performance leaves the others "in the
dust".

The filter (either Edmund or Thor labs sell them) will run about
$170-$200 however you cannot guarantee a performance increase with every
5065A as there are other parameters that must be met.

The main problem is finding one that is affordable!

Due to it's excellent short term stability (<1.5X10-13th at 100 Sec) it's
in high demand and prices have been increasing as the available ones get
snapped up!

As Bob noted a last production serial number (prefix 2816A) recently went
for $4000.00

Mid vintage ones can run $2000.00

If you don't need the 5065A performance then just buy a telecom one
whenever your current one dies!

Cheers,

Corby