... 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.
Granted, I've never built a maser, but personally I think the problems that would need to solving (and lead to learning) would be much more on the vacuum-systems, shielding and temperature long before electronics becomes a major factor. And the chance of actually get a result comparable to a commercial maser (or even just better than what you could realistically pick up from ebay for a few K) are pretty slim. And LOT of time and cash would be burned before you are even close to getting some sort of oscillation. A rubidium does look like a more realistic project.. Dont get me wrong - it would be beyond cool if someone built a homemade maser. The first ones were built by regular people in regular labs, so sure it can be done. Well, my $0.02 has been spent.. Ole > Den 10. jan. 2017 kl. 15.15 skrev Ole Petter Ronningen > <[email protected]>: > > Not sure how relevant that particular example is. PHM on Galileo was new > science (at least the sapphire loaded cavity), and *very* different > reliability engineering. > > AHM's are nothing new, the science hace been done, the construction is known, > down to exact drawings and circuit diagrams. There are numbers from 1982 that > can possibly be used as a startingpoint for estimating an amateur project in > https://library.nrao.edu/public/memos/vlba/main/VLBA_65.pdf > > As a side note, I am also not convinced that sourcing the fused quartz teflon > coated bulbs would be a show stopper for a limited number (<5) of masers, I > for one have one on my shelf. It is quite possible that old bulbs for > previous designs exists with the current manufacturers that they might be > willing to part with. > > They are also still manufactured, Vremya or one of the others might be > willing to sell them - although I have no idea about the cost. > > As another side note, on a trip to Switzerland I was allowed a glimpse of a > couple of the PHM's for Galileo in person. Impressive. > > Ole > >> On Tue, Jan 10, 2017 at 2:18 PM, ewkehren via time-nuts <[email protected]> >> wrote: >> Do we know what the PHM development for Galileo cost? >> >> >> >> >> Sent from Samsung tabletBob Camp <[email protected]> wrote:Hi >> >> > On Jan 10, 2017, at 2:45 AM, Dr. David Kirkby (Kirkby Microwave Ltd) >> > <[email protected]> wrote: >> > >> > Once 9 Jan 2017 12:59, "Bob Camp" <[email protected]> wrote: >> >> >> >> Hi >> >> >> >> Ok here are some rough numbers: >> >> >> >>> On Jan 9, 2017, at 4:35 AM, Dr. David Kirkby (Kirkby Microwave Ltd) < >> > [email protected]> wrote: >> > >> >>> It would be interesting to see your breakdown of the costs and man hours >> >>> for an H2 maser. I suspect that others would find cheaper/faster >> > solutions. >> >> >> >> $100M for the H2 >> >> >> >> $25M for the Rb >> > >> > With all due respect, and I apprectiate you have a good knowledge of this >> > field, but that's not a breakdown of costs or man hours I wanted to see, >> > but a cost which appears to be plucked from the air. >> >> Hardly plucked from the air. The last Rb design that I was involved with was >> roughly 5X that expensive. >> >> > >> > There's a BIG difference between a volunteer effort where >> > >> > * Salaries are not paid >> > * Items of test equipment are likely to be borrowed or people provide >> > access to them for no charge etc, >> > * Academics are likely to provide consultancy for free, in return for being >> > on papers published. >> > * Software licenses could probably be obtained free, or enough people get >> > trials. >> >> That’s where the 5:1 cost reduction comes from. >> >> > >> > compared to a commercial company building a maser where >> > >> > * Salaries are paid >> > * All equipment is purchased new >> > * Bench power supplies with 3.5 digit displays are sent out for calibration >> > each year. >> > * No outside body will do anything except at a commercial rate. >> > * Flights are booked for meetings which could be done over the Internet. >> > * High end software licenses are huge. >> > >> >> $500M for the fountain. >> > >> > But on what basis do you arrive at that figure? >> >> The numbers that the people who have done it come up with when you talk to >> them. >> >> > >> >> To get sponsorship for anything remotely close to those numbers, you >> >> need to have some massively good credentials. >> >> >> >> Bob >> > >> > Yes agreed at $500M. But someone like Tom, who does have massively good >> > credentials, could perhaps get $500,000, and perhaps that wisely spent >> > could get a fountain built. Without knowing how you arrive at $500M, it is >> > not possible for anyone to look at ways of shaving that cost. >> >> >> This is *not* a cheap field to be doing things in …. >> >> Bob >> >> > >> > The Lovell Telescope at Jodrell Bank in the UK was built on a shoestring >> > budget. It was at the time the world's largest steerable radio telephone. >> > Half a century later only 2 larger ones have been built. >> > >> > Maybe I am too nieve. >> > >> > Dave. >> > _______________________________________________ >> > time-nuts mailing list -- [email protected] >> > To unsubscribe, go to >> > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >> > and follow the instructions there. >> >> _______________________________________________ >> time-nuts mailing list -- [email protected] >> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >> and follow the instructions there. >> _______________________________________________ >> time-nuts mailing list -- [email protected] >> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >> and follow the instructions there. > _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
