My rubidium frequency standard (Accubeat AR60A) finally got its nice box with good cooling and some LED's showing the status. While watching the unlock LED I noticed the AR60 say's it is locked, about 4 or 5 minutes after cold start, when the frequency error jumps below about 1e-8 It takes 2 or 3 more minutes of slow drift to become stable within 1e-10. Is this to be expected? With this locking speed it is tempting to switch off the AR60A unless needed for some measurement. Would daily switching on/off have any impact on lifetime?

Hi Yes, that’s pretty normal operation for any of the telecom Rb’s. They also typically drift about 1x10^-9 over the first day of operation. It’s best to leave them running all the time. Second best is to turn them on a couple days before you need to use them. Bob > On Dec 11, 2021, at 2:23 AM, Erik Kaashoek <erik@kaashoek.com> wrote: > > My rubidium frequency standard (Accubeat AR60A) finally got its nice box with good cooling and some LED's showing the status. > While watching the unlock LED I noticed the AR60 say's it is locked, about 4 or 5 minutes after cold start, when the frequency error jumps below about 1e-8 > It takes 2 or 3 more minutes of slow drift to become stable within 1e-10. Is this to be expected? > With this locking speed it is tempting to switch off the AR60A unless needed for some measurement. Would daily switching on/off have any impact on lifetime? > _______________________________________________ > time-nuts mailing list -- time-nuts@lists.febo.com -- To unsubscribe send an email to time-nuts-leave@lists.febo.com > To unsubscribe, go to and follow the instructions there.

Totally agree with Bob. Same experience. On Sat, Dec 11, 2021 at 8:12 AM Bob kb8tq <kb8tq@n1k.org> wrote: > Hi > > Yes, that’s pretty normal operation for any of the telecom Rb’s. They > also typically drift about 1x10^-9 over the first day of operation. It’s > best to leave them running all the time. Second best is to turn them > on a couple days before you need to use them. > > Bob > > > On Dec 11, 2021, at 2:23 AM, Erik Kaashoek <erik@kaashoek.com> wrote: > > > > My rubidium frequency standard (Accubeat AR60A) finally got its nice box > with good cooling and some LED's showing the status. > > While watching the unlock LED I noticed the AR60 say's it is locked, > about 4 or 5 minutes after cold start, when the frequency error jumps below > about 1e-8 > > It takes 2 or 3 more minutes of slow drift to become stable within > 1e-10. Is this to be expected? > > With this locking speed it is tempting to switch off the AR60A unless > needed for some measurement. Would daily switching on/off have any impact > on lifetime? > > _______________________________________________ > > time-nuts mailing list -- time-nuts@lists.febo.com -- To unsubscribe > send an email to time-nuts-leave@lists.febo.com > > To unsubscribe, go to and follow the instructions there. > _______________________________________________ > time-nuts mailing list -- time-nuts@lists.febo.com -- To unsubscribe send > an email to time-nuts-leave@lists.febo.com > To unsubscribe, go to and follow the instructions there.

hi Paul, Bob, Is there a significant difference between these telco-surplus Rb and the more 'fancy' ones in this regard? I happen to own an Efratom MRK-HLN, which, I presume, is also more geared towards "always on". So, I wonder would the MRK be better or worse compared to a telco-surplus unit? Arguably a telco-surplus unit is also of the always-on variety or? best, Wilko (newbie trying to get a feel for this) > On 11 Dec 2021, at 16:27, paul swed <paulswedb@gmail.com> wrote: > > Totally agree with Bob. Same experience. > > >> On Sat, Dec 11, 2021 at 8:12 AM Bob kb8tq <kb8tq@n1k.org> wrote: >> >> Hi >> >> Yes, that’s pretty normal operation for any of the telecom Rb’s. They >> also typically drift about 1x10^-9 over the first day of operation. It’s >> best to leave them running all the time. Second best is to turn them >> on a couple days before you need to use them. >> >> Bob >> >>>> On Dec 11, 2021, at 2:23 AM, Erik Kaashoek <erik@kaashoek.com> wrote: >>> >>> My rubidium frequency standard (Accubeat AR60A) finally got its nice box >> with good cooling and some LED's showing the status. >>> While watching the unlock LED I noticed the AR60 say's it is locked, >> about 4 or 5 minutes after cold start, when the frequency error jumps below >> about 1e-8 >>> It takes 2 or 3 more minutes of slow drift to become stable within >> 1e-10. Is this to be expected? >>> With this locking speed it is tempting to switch off the AR60A unless >> needed for some measurement. Would daily switching on/off have any impact >> on lifetime? >>> _______________________________________________ >>> time-nuts mailing list -- time-nuts@lists.febo.com -- To unsubscribe >> send an email to time-nuts-leave@lists.febo.com >>> To unsubscribe, go to and follow the instructions there. >> _______________________________________________ >> time-nuts mailing list -- time-nuts@lists.febo.com -- To unsubscribe send >> an email to time-nuts-leave@lists.febo.com >> To unsubscribe, go to and follow the instructions there. > _______________________________________________ > time-nuts mailing list -- time-nuts@lists.febo.com -- To unsubscribe send an email to time-nuts-leave@lists.febo.com > To unsubscribe, go to and follow the instructions there.

Wilco Great to hear from you. Here is my 10 cents. Most of the things we happen to find are generally of the telco grade. The FRS as an example is a nicely built unit that used to be had for as little as $25. I picked a few up. Well maybe 8. These had all been in service (approx 1994) and so after a while they tended to suffer the plating out of the RB on the lamp. Ending the useful life. Thanks to time-nuts its been shown you can melt the RB off the lamp and you are back in business. For me at least another 5 years. The better units most likely have better reserve in the lamp. Maybe easier to repair and be stabilized perhaps a bit better. I would trust Bob's thoughts, thats why mine is worth 10 cents. Regards Paul WB8TSL On Sat, Dec 11, 2021 at 1:37 PM Wilko Bulte <wkb@xs4all.nl> wrote: > hi Paul, Bob, > > Is there a significant difference between these telco-surplus Rb and the > more 'fancy' ones in this regard? > > I happen to own an Efratom MRK-HLN, which, I presume, is also more geared > towards "always on". So, I wonder would the MRK be better or worse compared > to a telco-surplus unit? Arguably a telco-surplus unit is also of the > always-on variety or? > > best, > Wilko > (newbie trying to get a feel for this) > > > On 11 Dec 2021, at 16:27, paul swed <paulswedb@gmail.com> wrote: > > > > Totally agree with Bob. Same experience. > > > > > >> On Sat, Dec 11, 2021 at 8:12 AM Bob kb8tq <kb8tq@n1k.org> wrote: > >> > >> Hi > >> > >> Yes, that’s pretty normal operation for any of the telecom Rb’s. They > >> also typically drift about 1x10^-9 over the first day of operation. It’s > >> best to leave them running all the time. Second best is to turn them > >> on a couple days before you need to use them. > >> > >> Bob > >> > >>>> On Dec 11, 2021, at 2:23 AM, Erik Kaashoek <erik@kaashoek.com> wrote: > >>> > >>> My rubidium frequency standard (Accubeat AR60A) finally got its nice > box > >> with good cooling and some LED's showing the status. > >>> While watching the unlock LED I noticed the AR60 say's it is locked, > >> about 4 or 5 minutes after cold start, when the frequency error jumps > below > >> about 1e-8 > >>> It takes 2 or 3 more minutes of slow drift to become stable within > >> 1e-10. Is this to be expected? > >>> With this locking speed it is tempting to switch off the AR60A unless > >> needed for some measurement. Would daily switching on/off have any > impact > >> on lifetime? > >>> _______________________________________________ > >>> time-nuts mailing list -- time-nuts@lists.febo.com -- To unsubscribe > >> send an email to time-nuts-leave@lists.febo.com > >>> To unsubscribe, go to and follow the instructions there. > >> _______________________________________________ > >> time-nuts mailing list -- time-nuts@lists.febo.com -- To unsubscribe > send > >> an email to time-nuts-leave@lists.febo.com > >> To unsubscribe, go to and follow the instructions there. > > _______________________________________________ > > time-nuts mailing list -- time-nuts@lists.febo.com -- To unsubscribe > send an email to time-nuts-leave@lists.febo.com > > To unsubscribe, go to and follow the instructions there. > _______________________________________________ > time-nuts mailing list -- time-nuts@lists.febo.com -- To unsubscribe send > an email to time-nuts-leave@lists.febo.com > To unsubscribe, go to and follow the instructions there.

Hi The Efratom “big” Rb’s are sort of an early version of the telco devices. Their design dates back well before the smaller units came out. There also are very similar devices made by EG&G ( we wanted a part of that market, back in the day ….). Bob > On Dec 11, 2021, at 10:59 AM, Wilko Bulte <wkb@xs4all.nl> wrote: > > hi Paul, Bob, > > Is there a significant difference between these telco-surplus Rb and the more 'fancy' ones in this regard? > > I happen to own an Efratom MRK-HLN, which, I presume, is also more geared towards "always on". So, I wonder would the MRK be better or worse compared to a telco-surplus unit? Arguably a telco-surplus unit is also of the always-on variety or? > > best, > Wilko > (newbie trying to get a feel for this) > >> On 11 Dec 2021, at 16:27, paul swed <paulswedb@gmail.com> wrote: >> >> Totally agree with Bob. Same experience. >> >> >>> On Sat, Dec 11, 2021 at 8:12 AM Bob kb8tq <kb8tq@n1k.org> wrote: >>> >>> Hi >>> >>> Yes, that’s pretty normal operation for any of the telecom Rb’s. They >>> also typically drift about 1x10^-9 over the first day of operation. It’s >>> best to leave them running all the time. Second best is to turn them >>> on a couple days before you need to use them. >>> >>> Bob >>> >>>>> On Dec 11, 2021, at 2:23 AM, Erik Kaashoek <erik@kaashoek.com> wrote: >>>> >>>> My rubidium frequency standard (Accubeat AR60A) finally got its nice box >>> with good cooling and some LED's showing the status. >>>> While watching the unlock LED I noticed the AR60 say's it is locked, >>> about 4 or 5 minutes after cold start, when the frequency error jumps below >>> about 1e-8 >>>> It takes 2 or 3 more minutes of slow drift to become stable within >>> 1e-10. Is this to be expected? >>>> With this locking speed it is tempting to switch off the AR60A unless >>> needed for some measurement. Would daily switching on/off have any impact >>> on lifetime? >>>> _______________________________________________ >>>> time-nuts mailing list -- time-nuts@lists.febo.com -- To unsubscribe >>> send an email to time-nuts-leave@lists.febo.com >>>> To unsubscribe, go to and follow the instructions there. >>> _______________________________________________ >>> time-nuts mailing list -- time-nuts@lists.febo.com -- To unsubscribe send >>> an email to time-nuts-leave@lists.febo.com >>> To unsubscribe, go to and follow the instructions there. >> _______________________________________________ >> time-nuts mailing list -- time-nuts@lists.febo.com -- To unsubscribe send an email to time-nuts-leave@lists.febo.com >> To unsubscribe, go to and follow the instructions there. > _______________________________________________ > time-nuts mailing list -- time-nuts@lists.febo.com -- To unsubscribe send an email to time-nuts-leave@lists.febo.com > To unsubscribe, go to and follow the instructions there.