[time-nuts] hm H Maser

[paul swed]

I have enjoyed reading the thread and learned a bit. But given some of the
other threads I have read on improving RBs and CS's don't they make more
sense for most Time Nuts. I mean the conversations in the $100K and above
and outside of being fun to read doesn't make sense at all.
If I had $100K I would buy a new CS or slightly worn and save the rest...

There is a very real aspect of the conversation thats very interesting. Say
you are building a maser thats as good as a C or maybe not quite. The fact
that it can be refilled does give the system a very very long life. What
opportunity does this give you in simplifying the design and cost? What is
the thing thats driving up the cost?
Hex pole magnets, the cavity....

Regards
Paul.
WB8TSL





On Tue, Jan 10, 2017 at 6:02 PM, Bob kb8tq <kb8tq at n1k.org> wrote:

> Hi
>
> > On Jan 10, 2017, at 5:26 PM, Bob Stewart <bob at evoria.net> wrote:
> >
> > This may be a dumb question, but how much of an H Maser's advantage over
> a Cs Standard, for us mere mortal time-nuts, is down to the output
> oscillator it uses, rather than the reference source (H MASER or Cs beam)?
>
> Pretty much none. You *can* design one with a crummy OCXO, but the
> question becomes - why would you do that? Putting a $10,000 OCXO into a
> $150K device is not that big a deal. If you put the same OCXO into a Cs
> standard, it would run a bit better out to the cross over point (a few 100
> seconds or so). Indeed *some* Cs standards have such OCXO’s in them and
> that’s what they do.
>
> Bob
>
> > Bob
> >
> >      From: Dr. David Kirkby (Kirkby Microwave Ltd) <
> drkirkby at kirkbymicrowave.co.uk>
> > To: Discussion of precise time and frequency measurement <
> time-nuts at febo.com>
> > Sent: Tuesday, January 10, 2017 4:12 PM
> > Subject: Re: [time-nuts] hm H Maser
> >
> > On 10 January 2017 at 15:35, Ole Petter Rønningen <opronningen at gmail.com
> >
> > wrote:
> >
> >> ... having said that, I for one think I'm with Bob on this one. The
> thing
> >> about masers are that they are big. At least active masers. And they
> >> require a substantial volume be kept at ultra high vacuum - which is not
> >> trivial, especially not in a homeshop. The cavity needs to be kept at a
> >> temperature stable to 0.001 degree C. With 4-5 magnetic shields. Add to
> >> this costly pumps to keep the vacuum this low even if you succeed at
> >> reaching that vacuum.. There's easily 1-2KUSD running cost per year
> just to
> >> keep the maser running.
> >>
> >
> > Looking at the Microsemi MHM 2010 Active Hydogen Maser data sheet, the
> > maser has a peak power of 150 W and an operating power of 75 W.  Based
> on a
> > power consumption of 75 W, that is 657 kW hr / year of energy. I pay
> around
> > £0.20 (GBP) per kW hr for electricity, so that's £131 (GBP) annually. I
> > believe electricity is cheaper in the USA than here in the UK, but
> > converting £131 (GBP) to USD, that's around $161/year in electricity. So
> > running costs don't seem to be an issue.
> >
> > But I must admit, the thought of spending a lot of time/money to build
> > something I could have bought for a lot less with higher performance is
> not
> > that attractive, although of course there would be a satisfaction from
> > building it yourself.
> >
> > Dave
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