[time-nuts] Thinking outside the box a super reference
kb8tq at n1k.org
Thu Nov 3 20:59:46 EDT 2016
Ok, how many full performance Hydrogen Masers can you build (size is not an issue) and
deliver for < $10,000 (2X Bert’s number) ?
> On Nov 3, 2016, at 8:55 PM, Tim Shoppa <tshoppa at gmail.com> wrote:
> It would obviously be larger than a homebrew Cs, but why not a homebrew
> Hydrogen Maser Frequency standard?
> The commercial Cs units always seemed objects of pure miniaturized hi-tech
> materials science magic, while the Hydrogen Masers I've seen seem much
> larger-scale\ and more a matter of vacuum plumbing. Obviously the materials
> cost for the copper microwave cavity will be very large, and I'm sure
> Teflon-coating a quartz chamber is an art, but the pumps and magnets are
> very familiar from my years in grad school working with plasma kettles and
> mass spectrometers.
> Tim N3QE
> On Thu, Nov 3, 2016 at 4:07 PM, Bert Kehren via time-nuts <
> time-nuts at febo.com> wrote:
>> 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
>> 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
>> to monitor, record and analyze on a continuous basis preferably with out
>> tying up expensive equipment. We have the pieces in place and looking
>> 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
>> is working combining the GPSDO data stream with the data from the unit
>> 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
>> ’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
>> performance was not an issue. That changed when Corby introduced me to
>> 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
>> 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
>> 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
>> 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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