Hello Time-Nuts, I appreciate all the kind remarks regarding yesterday's post. Today the maser was tested on each of the attached power supplies and on battery power. Unit stayed lit and locked, and the alarm went off when on just battery. So, all the covers were replaced and the readings logged. We'll see where things stand in a week or so after it has had time to settle and reach its new thermal equilibrium. Sigma Tau Standards Corporation was the fist and only commercial manufacturer of hydrogen masers in the U.S., in fact, I believe there are only three companies world-wide (the other two being in Russia - Kvarz and ?). Harry Peters retired from NASA in 1975 after building several units there, and moved to Alabama to found Sigma Tau. Over the years Sigma Tau was bought by Symmetricom (when Harry Peters retired again), Symmetricom was purchased by MciroSemi, and MicroSemi was purchased by Microchip. The division is still active and producing product in Alabama. There is at least one of the old guard left from Sigma Tau, Bryan Owings. He was consulted on several occasions when the maser was trying to be coaxed into operation. It was VERY clear that he has seen many of these units and knows the intimate details of their construction. Have to say that I learned a few things from him as well. If you need some light reading on hydrogen masers you might try the following link - https://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19740008078.pdf It is from 1973 by Harry Peters and keeps it pretty basic. I don't think there was ever a commercial version of a variable volume unit, but it makes a good research tool. I hope to post again some months out when we have some data. Skip Withrow

Hi, On 2020-01-17 22:09, Skip Withrow wrote: > Hello Time-Nuts, > > I appreciate all the kind remarks regarding yesterday's post. > > Today the maser was tested on each of the attached power supplies and > on battery power. Unit stayed lit and locked, and the alarm went off > when on just battery. So, all the covers were replaced and the > readings logged. We'll see where things stand in a week or so after > it has had time to settle and reach its new thermal equilibrium. Good progress. > Sigma Tau Standards Corporation was the fist and only commercial > manufacturer of hydrogen masers in the U.S., in fact, I believe there > are only three companies world-wide (the other two being in Russia - > Kvarz and ?). T4Science, which is where the team from Observatoir Cantonell de Neuchatel (ON) ended up, for a while also through Oscilloquartz. The Kvarz masers have been repackaged by severals, such as Oscilloquartz. I only have a rubidium from the pre-cursor to Kvarz. I aim to bring that back into operations again. > Harry Peters retired from NASA in 1975 after building > several units there, and moved to Alabama to found Sigma Tau. Over > the years Sigma Tau was bought by Symmetricom (when Harry Peters > retired again), Symmetricom was purchased by MciroSemi, and MicroSemi > was purchased by Microchip. The division is still active and > producing product in Alabama. Sigma Tau went up into DATUM and then Symmetricom bought DATUM as I recall it. > > There is at least one of the old guard left from Sigma Tau, Bryan > Owings. He was consulted on several occasions when the maser was > trying to be coaxed into operation. It was VERY clear that he has > seen many of these units and knows the intimate details of their > construction. Have to say that I learned a few things from him as > well. Masers is quite a different beasts from your normal beam clock, in several ways. You become much more aware about things, and to some degree they are more open. You learn a lot with these things. > If you need some light reading on hydrogen masers you might try the > following link - > https://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19740008078.pdf > It is from 1973 by Harry Peters and keeps it pretty basic. I don't > think there was ever a commercial version of a variable volume unit, > but it makes a good research tool. > > I hope to post again some months out when we have some data. Look forward to hear more! Cheers, Magnus