[time-nuts] Cold Rubidium over hyped?

[cdelect at juno.com]

Well I have been looking at the data in the 

https://www.researchgate.net/publication/325499937_A_portable_cold_87_Rb_
atomic_clock_with_frequency_instability_at_one_day_in_the_10-15_range

link and find that maybe they are overstating their performance!

In the plot of figure 5 my HP 5065A almost perfectly matches the Allan
deviation 
out to 1000 Sec.! (Although mine does have VERY good performance)

Also if you look at figure 7 all the Maser data shown seems to be from
poorly
operating Masers so any judgement of better clock performance versus the
Masers
is a bit much!

The figure 5 data looks much better but still is not beating a good
active Maser.

The EFOS2 a 1982 vintage Maser as well as the MHM 2010 and several other
modern Masers
I could find data for show between 2 and 5X10-15th at 1000 Sec.
The MHM 2010 specs at 5X10-15th at 100Sec and 2.0X10-15th at 1000Sec
All the Masers shown are worse than that spec!
Also my old Kvarz passive maser has  2x10-13th at 100 Sec just shy of 
matching the top two Masers at 100Sec, which I don't believe!

Something does not add up in their data!

So I'm not really that impressed and would take an Active or Passive
Maser anyday.

Just wonder if some  5065A can get so impressive that they don't just
make a modern large/cool cell classic Rubidium with modern electronics
technology! Certainly would be cheaper and more long lived also.

Just my thoughts!

Cheers,

Corby