[time-nuts] hm H Maser
William H. Fite
omniryx at gmail.com
Sun Jan 8 11:57:29 EST 2017
Bob, I think you're missing the point here. This is not the quest for
utimate standards of accuracy/precision/resolution, it Is not about
economic viability, or even attainability, let alone being "worth the
It is about a fun project. Fun even if it comes to nothing. Is that
difficult to understand?
On Sunday, January 8, 2017, Bob Camp <kb8tq at n1k.org> wrote:
> > On Jan 8, 2017, at 11:21 AM, Dr. David Kirkby (Kirkby Microwave Ltd) <
> >> Hi
> >> I guess the question then would be:
> >> Is a H Maser that runs 6.6 x 10^-12 at 1 second worth the trouble?
> >> With 100 KHz / C temperature coefficients running around, getting
> >> good stability in a real world setting at 1 day will be “interesting”.
> >> Just for reference: The MH-2010 data sheet shows 1.5x10^-13 at
> >> 1 second for the “cheap” version and 8x10^-14 at one second for
> >> the low noise version. Data showing the 5065 Rb at 1x10^-12 at
> >> 1 second is running around on various web sites.
> >> The NIST paper suggests that they made several prototypes before
> >> they got one good one working. That’s a lot of “fun and games” with
> >> ceramic machine lathes and Rb magnetometers…..
> >> The punch line being - would the same effort / cost / many years of time
> >> be more
> >> fruitful (ADEV wise) doing a large package Rb (like a 5065) ? Based on
> >> the number of people making them in volume over the years, Rb’s appear
> >> be the easier item to debug, design, and build.
> >> Bob
> > If you build a H2 maser, you would learn a lot more than building a bunch
> > of rubidiums. That sounds a good enough reason to me.
> I’m not sure I agree with that. Both have their own issues. Much of the
> in both cases involves fiddly mechanical and machining details. Working
> out by a lot of trial and error would be useful for that particular
> standard. It’s hard
> to see how it would be useful for much else …. Yes, there is a bunch of
> physics involved in each, but again it’s very use specific stuff.
> > I've been contemplating buying one of the older HP 5061A or 5061B cesium
> > frequency standards from eBay. Almost all are sold as "for spares or
> > repair", and are probably not going to be economically viable to get
> > working due to the fact the tubes are probably useless. But I'd sure
> > a lot from playing around inside one of the older ones.
> > Dave
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