Hi That 106 comes up *fast*. Take a look at the GR equivalent if you want to see slow…..
Bob On Oct 2, 2014, at 2:58 PM, Tom Van Baak <t...@leapsecond.com> wrote: > The most extreme example of slow ovenized oscillator warm-up I've seen is the > vintage hp106. These mid-1960's oscillators were designed as the ultimate, > "hp way", pre-atomic, frequency standard -- expected to be powered up, > uninterrupted, for years and decades. So there was no hurry in the (perhaps > once-in-a-lifetime) initial warm-up. Here's a plot/photo of one I recently > tested: > > http://leapsecond.com/museum/hp106a/ > > These HP-106 oscillators are among the best I have ever measured: stability > and daily drift rates in the very low -13's. Like the SR-71, these were > designed by gut and slide rule. And yet achieved extreme performance, even by > today's standards. > > The amazing thing -- as you know from your enviable career at HP -- is that > an instrument produced in 1964 can still work 50 years later in 2014. No > blown fuses, no electrolytics, no filaments, no f/w upgrades, no Y2K, no > decaying EEPROM, no batteries, not even any IC's. No user s/w, no USB, no > drivers, no OS. Not even an on/off switch! Just a 5-pin 24VDC backup or > 2-prong AC cord in and a pure 5 MHz BNC out, that's all. > > How many of the instruments we use today will still work out-of-the-box in > 2064? > > /tvb > > ----- Original Message ----- > From: "Richard (Rick) Karlquist" <rich...@karlquist.com> > To: "Discussion of precise time and frequency measurement" > <time-nuts@febo.com> > Cc: <hmur...@megapathdsl.net> > Sent: Wednesday, October 01, 2014 9:03 PM > Subject: Re: [time-nuts] How long do ovens take to cool to ambient after > power is removed? > > >> On 10/1/2014 1:04 PM, Hal Murray wrote: >>> >>> drkir...@kirkbymicrowave.co.uk said: >>>> Anyway, later today (tomorrow ??) I will post a plot of frequency vs time. >>>> The question is though, how long is thing thing likely to take too cool? >>> >>> I'd expect an exponential decay so you need to specify how close to ambient >>> you want to get. I'd guess a ballpark of 10x the warm up rate. >>> >>> You can probably measure it if you have the warmup graph. Turn it off, wait >>> a while, turn it on, measure the freq, consult warmup graph. >> >> When I was still with Agilent, I did some experiments with unpowered >> 10811's. Both the oven and oscillator were unpowered and I measured >> the temperature by looking at the B mode resonance of the crystal. >> I wanted to get rid of any linear frequency drift. As a rough >> rule of thumb, 1 hour of cool down is pretty good for most purposes. >> For extreme measurements, I would allow 10 hours. This reduced >> any exponential tail to below the ability to measure temperature and/or >> below the effects of the ambient. I had to put a box over it to >> reduce the effects of air currents. If I did not do that, then 1 hour >> was all I needed. >> >> Rick Karlquist N6RK > > > _______________________________________________ > time-nuts mailing list -- time-nuts@febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. _______________________________________________ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
