After many yeaqrs admiring form afar, I've acquired my first piece of timenuttery, an Efratom PC-10 portable rubidium clock, S/N 101 (possibly the first production unit?). It has the usual decade sine and ttl outputs plus a front panel intervalometer or clock, or at least that's as much as I've figured out since it came with no documentation whatsoever It warms up, the unlock light and crsytal adjust lights go out, and it seems to keep time as accurately as anything I can measure it against (no surprise). The 10MHz output beats dead on to my recently retuned HF rig. It's a great little unit but I could use some more information on e.g. the phase shift adjustment which seems to allow you to discipline it with a front panel 1PPS input but isn't super obvious, as well as maintenance, calibraiton, and test. As far as I can tell Microsemi, who bought Microchip, who bought Symmetricom, who bought Datum, who bought Efratom, have never heard of this adorable little beast, nor has the internet. Google image search mostly returns pictures of my unit (I know there's at least one other one out there as it has a different front panel switch). It's based on an Efratom FRK-H oscillator, but does anyone know anything at all about the PC-10 specifically? I'd love any docs you have. Some quick and dirty photos at https://www.flickr.com/photos/9100973@N06/albums/72157711587895206 --more to come. thanks, david n8qg

In an eBay search I found several PC-10s for sale. One of them had a Ball logo as part of the model/serial number sticker. Ball Efratom Division PC-10 Portable Clock ATOMIC CLOCK Don Resor N6KAW Sent from someone's iPhone > On Nov 1, 2019, at 12:04 AM, David Bliss <n8qg@dbsi.org> wrote: > > After many yeaqrs admiring form afar, I've acquired my first > piece of timenuttery, an Efratom PC-10 portable rubidium clock, S/N 101 > (possibly the first production unit?). It has the usual decade sine > and ttl outputs plus a front panel intervalometer or clock, or at least > that's as much as I've figured out since it came with no documentation > whatsoever > > It warms up, the unlock light and crsytal adjust lights go out, and it > seems to keep time as accurately as anything I can measure it against > (no surprise). The 10MHz output beats dead on to my recently retuned HF > rig. > > It's a great little unit but I could use some more information on e.g. > the phase shift adjustment which seems to allow you to discipline it > with a front panel 1PPS input but isn't super obvious, as well as > maintenance, calibraiton, and test. > > As far as I can tell Microsemi, who bought Microchip, who bought > Symmetricom, who bought Datum, who bought Efratom, have never heard of > this adorable little beast, nor has the internet. Google image search > mostly returns pictures of my unit (I know there's at least one other > one out there as it has a different front panel switch). > > It's based on an Efratom FRK-H oscillator, but does anyone know anything > at all about the PC-10 specifically? I'd love any docs you have. > > Some quick and dirty photos at > https://www.flickr.com/photos/9100973@N06/albums/72157711587895206 --more to come. > > thanks, > david n8qg > > > _______________________________________________ > time-nuts mailing list -- time-nuts@lists.febo.com > To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com > and follow the instructions there. >

Hi I was about to mention that there actually are a few more steps in the “who bought who” chain :) The date codes put this back to 1992. That’s a long time in “internet years”. Portable clocks were made for a variety of markets. It’s not even clear which market this one was aimed at. Obviously it stayed in service a *long* time doing something for somebody (one would guess a mobile cal lab ). The FRK-H that is at the heart of the beast does have information out in the wild. In addition several list members have done deep dives into the internals of the device. Keeping that part running should be very possible. Bob > On Nov 1, 2019, at 4:03 AM, Don R <organlists1@sonic.net> wrote: > > > In an eBay search I found several PC-10s for sale. One of them had a Ball logo as part of the model/serial number sticker. > > Ball Efratom Division PC-10 Portable Clock ATOMIC CLOCK > > > Don Resor > N6KAW > > Sent from someone's iPhone > >> On Nov 1, 2019, at 12:04 AM, David Bliss <n8qg@dbsi.org> wrote: >> >> After many yeaqrs admiring form afar, I've acquired my first >> piece of timenuttery, an Efratom PC-10 portable rubidium clock, S/N 101 >> (possibly the first production unit?). It has the usual decade sine >> and ttl outputs plus a front panel intervalometer or clock, or at least >> that's as much as I've figured out since it came with no documentation >> whatsoever >> >> It warms up, the unlock light and crsytal adjust lights go out, and it >> seems to keep time as accurately as anything I can measure it against >> (no surprise). The 10MHz output beats dead on to my recently retuned HF >> rig. >> >> It's a great little unit but I could use some more information on e.g. >> the phase shift adjustment which seems to allow you to discipline it >> with a front panel 1PPS input but isn't super obvious, as well as >> maintenance, calibraiton, and test. >> >> As far as I can tell Microsemi, who bought Microchip, who bought >> Symmetricom, who bought Datum, who bought Efratom, have never heard of >> this adorable little beast, nor has the internet. Google image search >> mostly returns pictures of my unit (I know there's at least one other >> one out there as it has a different front panel switch). >> >> It's based on an Efratom FRK-H oscillator, but does anyone know anything >> at all about the PC-10 specifically? I'd love any docs you have. >> >> Some quick and dirty photos at >> https://www.flickr.com/photos/9100973@N06/albums/72157711587895206 --more to come. >> >> thanks, >> david n8qg >> >> >> _______________________________________________ >> time-nuts mailing list -- time-nuts@lists.febo.com >> To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com >> and follow the instructions there. >> > _______________________________________________ > time-nuts mailing list -- time-nuts@lists.febo.com > To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com > and follow the instructions there.