[time-nuts] Thinking outside the box a super reference

EWKehren at aol.com EWKehren at aol.com
Thu Nov 3 16:07:59 EDT 2016

Over the past there has been talk about building from  scratch high 
performance references. I think consensus was that it is out of  reach. In the mean 
time Corby is reworking an active maser which takes a lot of  know how. But 
let us look at his work on the super HP5065. It is able to  outperform a 
passive maser in the below 100 second range! Long term a proper  GPSDO should 
be possible to step in. We are working on it including pressure and  
temperature control. To make full use of it you also need to have the capability  
to monitor, record and analyze on a continuous basis preferably with out 
tying  up expensive equipment. We have the pieces in place and looking forward 
of  combining all the pieces and compare with Corby’s active Maser. We are 
back to  the GPSDO after being distracted by Tbolt performance. A third party 
is working  combining the GPSDO data stream with the data from the unit that 
generates  frequency, pressure and temperature data along with time to a 
USB stick, while  also be able to monitor with a PC.  
I know it is considered by some heresy but our lack of a  Maser and in Juerg
’s case no access to one, we try to overcome it with a GPSDO  tailored for 
Rb and Cs and control our Cs’s C field .   
There was a time that I did have a HP5065A but got rid of  it when I got 
some Cs’s. My best counter was A HP5345 and even with a Tracor 527  1 second 
performance was not an issue. That changed when Corby introduced me to  time 
nuts and frankly it was the first  time I learned about ADEV. But the 
HP5065A was gone. Now I have a cell  that Corby has plotted and time permitting 
may become a project. 
Let me get to the real issue. There are not enough  HP5065A’s out there and 
not affordable for all time nuts. Most are being kept  and are not for 
sale. But if a combined effort by many time nuts it MAY be  possible to recreate 
the guts of the HP5065A. The key word is MAY. 200 time nuts  be willing to 
invest $ 5000 each may get us there. The market does not justify  such an 
effort but time nuts keep bringing up discussions. All the other ideas  kicked 
around in the past will cost more. There are some among us that know what  
it cost and who can make the key elements like lamps, cells, filters etc. 
Just a  thought outside the box and hopefully may turn in to a limited 
constructive  dialog. We will continue on our path, which include FRK/M100, HP5065 
and  Cs. 
We would not be capable to contribute technically on the  physics package 
but I would be willing to contribute financially and with  monitoring 
equipment even if I would not be around when finished. 
Bert Kehren

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