[time-nuts] Used Hydrogen Maser

[Michael Wouters]

I recently got some prices on Russian masers. The passive masers are about
$us90K and the active masers are about $US250K. There’s apparently quite a
bit of paperwork to do with the export licensing but it just needs a bit of
patience :-)


Cheers
Michael

On Thu, 11 Jul 2019 at 3:01 am, Bob kb8tq <kb8tq at n1k.org> wrote:

> Hi
>
> One of the gotcha’s if you are in the US is that the most often seen
> “alternate
> brand” of Maser comes out of Russia. Depending on the phase of the moon and
> just what the rule book says this week, you may well not be able to bring
> one
> into the country.
>
> Back when things were a bit more cordial and trade was more rational, the
> quoted
> price was in the $150 $200K range.
>
> Bob
>
> > On Jul 10, 2019, at 8:57 AM, Dana Whitlow <k8yumdoober at gmail.com> wrote:
> >
> > Perry,
> >
> > The only H-maser with which I've had direct experience (the MHM-2010)
> costs
> > around $250,000 new.  But there are some other brands, mostly foreign.
> >
> > The immediate operating cost is that of AC power.  IIRC, the '2010 uses
> > about
> > 100W or maybe 125W, *all the time*.  The H-maser is *not* the kind of
> thing
> > one
> > turns on when needed and back off in between uses.
> >
> > The hydrogen supply is usually large enough to last about 15 years or
> more.
> >
> > A sort of hidden cost is that the unit must be operated in a
> > temperature-controllled
> > environment for best stability- hence there is also the purchase and
> > operating costs
> > of a suitable A/C system.
> >
> > Also note that H-masers *do* drift in frequency over time.  The one we
> had
> > at Arecibo
> > typically needed frequency correction of about 3.5E-14 about every 4
> months
> > on average,
> > to keep the observatory's master clock on time within 25-50 nsec as
> needed
> > for certain
> > types of radio astronomy situations.  We used the H-maser because it has
> > the best
> > stability (over the range of seconds to hours) of anything commercially
> > available.
> >
> > The maser operated without difficulty for about the first 8 years before
> it
> > lost one of
> > its two vacion pumps.  We had to pay $12k for an engineer from
> Symmetricom
> > to
> > bring down a pair of new pumps and oversee the installation.  He replaced
> > the failed
> > one on one day while I took notes; then the next day I replaced the 2nd
> one
> > under
> > his close supervision and scrutiny.  Because the maser was well designed
> > with vacuum
> > isolation valves, both pump replacements were accomplished without
> shutting
> > down
> > the maser and with no disturbance to observations.
> >
> > A few years later the maser's internal log data showed that the hydrogen
> > pressure
> > was oscillating, along with synchronized fluctuations in drive to the Pd
> Pd
> > "valve",
> > with a period of about 11 days.   At this point there was no noticeable
> > effect on timing
> > accuracy.  A series of calls to Symmetricom customer service indicated
> that
> > they had
> > no idea what was going on, and they counseled "watchful waiting".  We did
> > that for
> > several more years up until I retired in Dec 2016, with the only change
> > being a very
> > gradual drift in oscillation period and amplitude.  The in late Dec 2018,
> > the maser
> > basically died outright, and Symmetricom (then part of Micro-Semi) was
> > unable to
> > provide a definite diagnosis- just a couple of theories.  But they
> advised
> > against
> > trying to fully diagnose and repair the unit, considering its advanced
> age
> > (approx
> > 15 years at the time).
> >
> > Hope this helps ...
> >
> > Dana
> >
> >
> >
> >
> > On Wed, Jul 10, 2019 at 7:00 AM Perry Sandeen via time-nuts <
> > time-nuts at lists.febo.com> wrote:
> >
> >> Yo Bubba Dudes!,
> >> OK, I'll finally ask the question that probably a lot of list members
> >> wanted to know but were reticent to ask.
> >> First, what is the price of one of a new Hydrogen Maser? (This is
> >> important if I win the lottery.)
> >> Second, what would be prices for used Hydrogen Maser in *reasonable*
> >> working condition and what might be the long term costs to keep it
> running?
> >> Thirdly, what are the chances of finding a used one?
> >> Then again, might it be better, money wise just to limp along with used
> HP
> >> Cs?
> >> Regards,
> >> Perrier
> >>
> >>
> >>
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