All of the available Rb standards that I've seen have a 10 MHz output, Some have a 1 PPS output as well.
The nice thing about a Rb is that its short term stability (seconds to minutes and perhaps even longer) is much better than that of a GPS timing receiver. The bad news is that Rb standards exhibit long term frequency drift in the neighborhood of a few parts in 10^11 per month. A pretty fair compromise is to use an Rb standard that is disciplined by GPS PPS pulses with a loop time constant on the order of a day or so. The SRS model PRS-10 seems to be well-regarded and can be had for $1500 factory new. Many are on sale by ebay and similar sources- however these are often left over from telecom service and are actually a modified model that has had the PPS locking facility removed so that the original buyer could save a few bucks. My PRS-10 is one of these. The Rb standards seem to prefer being powered up continuously, and if one is turned back on after any significant storage without power, it can cake several days to really settle down to its steady state behavior. Also, because of the long-term frequency drift, one must periodically retune the unit back on frequency by referring it to GPS. Both units I own (a PRS-10 and an L-PRO) have an analog tuner port, wherein application of 0 to 5V DC tunes the frequency of the Rb through the range of +/- a few parts in 10^9. This has been straightforward but a bit tedious; if I want to get it within a few parts in 10^12, even a good 10-turn pot is barely adequate to the task, and I'm sometimes turning the shaft through an angle so small that I'm not sure I even moved it until I've observed the phase drift against GPS for an hour or more. So, that's my version of Rb 101. See what others have to say as well, as I'm also fairly new at the game. Dana (K8YUM) On Mon, Sep 16, 2019 at 4:02 PM pisymbol . <[email protected]> wrote: > First off, thanks to everyone who replied. > > On Mon, Sep 16, 2019 at 11:00 AM Bob kb8tq <[email protected]> wrote: > > > What are you really trying to do here? > > > > Take over the world - one epoch at a time. > > If it’s a “from scratch” atomic standard, then you just aren’t going to get > > there. Sorry about that ... > > > > Ok. > > > > If it’s a wall clock sync’d to an external radio service then indeed you > > might get there. > > > > Well, I want something maybe in between. Currently I think I have that: I > have a RPi disciplined to the Adafruit Ultimate GPS HAT via chrony (PPS > etc.). This works well. > > > > In-between those two lie tings like buying eBay telecom Rubidium’s, > > attaching them to a power supply and you have a working standard. > > > > So I think this is what I'm talking about. I want something a little bit > more esoteric than a GPS 1PPS. Can you explain a bit about these > prepackaged Rubidium standards? Upside/downside etc. Do I have to > maintain/check these black boxes? > > > > Lots of very different directions this could go and and they all could be > > called an atomic clock …. Not at all knock on doing something, just > > confusion > > about what exactly you want to do. > > > > Again, take over the world. Sorry for not being upfront about that. That > would have made things A LOT clearer. > > So I guess: How can I get a simple Rubidium standard that outputs a > reference frequency as a discipline to say ntpd or chrony. > > Btw, I'm a noob. Please be gentle. > > -aps > _______________________________________________ > time-nuts mailing list -- [email protected] > To unsubscribe, go to > http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com > and follow the instructions there. > _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
