[time-nuts] Re: Efratom FRK with "inoperative lamp"
On Sat, 2022-02-05 at 20:48 +1100, Julien Goodwin wrote: > I /think/ it's using more power than it did before (right around 20W > at > total cold, dipping to 10W after a while), although silly me didn't > make > a note of it, but even after 30 minutes it's not locking. I don't have any experience with this brand/model, but I have resurrected some "dead" rubidium standards. I'm mostly going from experience with gas lasers, but I found the same approach worked on the rubidium units that I have here. It's well worth being patient with the lamp, if it's been off for many years, it may have a gas pressure/mix that's far from optimal. If you let it sit with the heater and exciter running, it may just strike after a while. (You should measure the current going into the exciter, it should jump up suddenly when the lamp strikes. Measure the unlit condition with the lamp cold and the exciter on. On mine, the current roughly doubles when it is lit.) If it does strike, keep it running for a few days, don't power it off. It can get even harder to light, before it gets easier again. You might consider using a UPS for this procedure, as Murphy could strike just after the lamp does! On one of my units, I had to manually run the lamp heater to a higher than normal temperature, before it would light. (With a thermocouple, it's best to use some heatsink grease, otherwise the readings can be a long way off.) The needed temperature gradually came down, until the unit could be reassembled and used normally. On another, I just waited for several hours at the usual temperature, and that was enough. Although again, it took a couple of days of operation before it would light without hesitation. On yet another unit, the lamp would light normally, but the photodiode signal was too weak to achieve a lock. (The firmware said nope.) So I just left it running overnight, and then after a power cycle, it locked immediately! So I wanted to point out that if the lamp has everything it needs, and still won't light, you might just need to leave it powered for a while. And you have not much to lose, if you need to run it at a higher temperature for a while. Have fun, Darren ___ time-nuts mailing list -- time-nuts@lists.febo.com -- To unsubscribe send an email to time-nuts-le...@lists.febo.com To unsubscribe, go to and follow the instructions there.
[time-nuts] Re: Leap indicator set to 1 !
Hi all, this appears to be the explanation for the bogus leap second: https://berthub.eu/articles/posts/leapseconds-expose-bugs-even-when-they-dont-happen/ Have fun, Darren On Sat, 2021-11-27 at 09:22 -0600, Steven Sommars wrote: > FYI. > > At 2021-11-27 00:00:00 UTC many public NTP servers began setting the > leap > indicator to 1. > This may be gpsd related > ___ > time-nuts mailing list -- time-nuts@lists.febo.com -- To unsubscribe > send an email to time-nuts-le...@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-le...@lists.febo.com To unsubscribe, go to and follow the instructions there.
[time-nuts] Re: 1 pps
On Thu, 2021-11-11 at 14:07 +, Andy Talbot wrote: > I made a 5MHz doubler plus distribution for my HP5061. You can see > the > design at http://g4jnt.com/10MHzDist.pdf The doubler is a full wave It's worth noting that the HP5370A has a doubler on the reference input. It will accept either 5 or 10 MHz, and in the case of 5 MHz, it doubles. It may not be as clean as what you need, but the full schematic is in the service manual. There is a reasonable chance that I could measure mine and see if it comes close. Bear in mind that it converts to a square wave in order to drive the counter, but also back to a sine wave for the reference output. Have fun, Darren ___ time-nuts mailing list -- time-nuts@lists.febo.com -- To unsubscribe send an email to time-nuts-le...@lists.febo.com To unsubscribe, go to and follow the instructions there.
[time-nuts] Re: Ryzen mobos with serial port for Garmin GPS?
On Thu, 2021-11-04 at 22:36 -0700, Rich Wales wrote: > However, mobos with a serial port are becoming harder to find. That's not really been my experience, they just moved it to a header. You will need to supply a DE9 to ribbon cable, say on a bracket, or installed in a cutout elsewhere in the case. This is the first one that I checked, and it has such a port labelled COMA, along the left/bottom edge. https://www.gigabyte.com/Motherboard/B450-AORUS-M-rev-1x/sp#sp Also note that the Linux PPS driver supports the standard PC parallel port, which you can usually find as a header. If you are having performance issues with one, try the other. (But you may need to supply negative-going edges to the parallel port.) Have fun, Darren ___ time-nuts mailing list -- time-nuts@lists.febo.com -- To unsubscribe send an email to time-nuts-le...@lists.febo.com To unsubscribe, go to and follow the instructions there.
[time-nuts] Re: Query about List and about 10 MHz Distro
On Sun, 2021-08-29 at 09:21 -0500, Dana Whitlow wrote: > I believe that a significant problem in my case was not leakage > through the > shield, but > rather common-mode currents on the cable. My experiences were with > RG-6 > style cable, Chiming in with a maybe tangential issue. I had some really unreliable strange behaviour in my lab, and I traced it to some low quality BNC crimp plugs. The noise at my receiver would fluctuate by tens of dB, as I wiggled the connector. With a good connector, it's dead quiet all of the time. My conclusion was that the outer conductor was not making contact when the plug was mated with a socket, and so outer currents were flowing through the spring, and through the part of the plug that you rotate when locking it to the socket. That adds some impedance, and your receiver is now also listening to the common-mode current, that should flow harmlessly to the chassis. Visually, you can spot these particular bad plugs from the lack of slots in the outer conductor. There's no way for it to compress as it's mated with the socket, so they are under-sized instead. They often feel loose. It may work sometimes, but not with all sockets, and only if gravity is pulling on the cable just right. All of the ones I've received from China have been like this. They went in the bin. The ones from Jaycar, my local electronics shop, appear to be identical. I used them anyway, because I was travelling a lot. Since that time, I have been cutting them off my cables, hopefully I've gotten them all. It's been a sad lesson. Time and money down the drain, but at least I worked out what was going on in the end. Maybe someone else is struggling with this issue? Try wiggling all the connectors :) Have fun, Darren ___ time-nuts mailing list -- time-nuts@lists.febo.com -- To unsubscribe send an email to time-nuts-le...@lists.febo.com To unsubscribe, go to and follow the instructions there.
