Re: [time-nuts] PRS-10 Warm-up Time, Calibrating/Adjusting, and long-term poweron
We have operated about 40 PRS10s over the past 20 years or so. These are all run continuously in benign environments and monitored via GPS time-transfer . Some have died after just over a year; others have operated for more than 12 years. A new one generally takes a few months to burn in, before its frequency drift stabilises to something like the specifications. They do not behave very predictably, showing sudden changes in frequency and so on. One exhibited frequent steps for a few years and then the problem went away. Trying to predict what they would do at the level of better than a few parts in 10^11 seems difficult. Cheers Michael On Sat, 9 Mar 2019 at 3:03 am, Attila Kinali wrote: > On Fri, 8 Mar 2019 06:31:48 -0600 > Dana Whitlow wrote: > > > The point here is that there are apparently a number of warm up drift > > mechanisms operating, some of which take days to sensibly settle down. > > Longer. I know of one measurement, where the Rb had a kind of stable > drift until it suddenly switched to another slope quite suddenly > (within a few days) about half a year after power up. > > The aging mechanisms of Rb vapor cell standards are many and not > all of them are well understood, much less controlled. Compared > to that, an OCXO has "only" thermal stability of the oven, strain > relaxation of the holder/crystal and deposition/removal of contaminants > on the crystal surface. Ok, there are a couple more, but these three > are the main contributors for most OCXO out there. While for the > Rb vapor cell standard I could name you half a dozen just like that > and I am far from being an expert on these. > > For those interested, John Vig wrote a couple of papers on the aging > of OCXO in the 80s and 90s. The topic of Rb vapor cell aging is a lot > more messy and I don't know whether there is any good paper that reviews > the main contributors. > > Attila Kinali > -- > It is upon moral qualities that a society is ultimately founded. All > the prosperity and technological sophistication in the world is of no > use without that foundation. > -- Miss Matheson, The Diamond Age, Neal Stephenson > > ___ > 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.
Re: [time-nuts] Helium leaks
Hi Jim: When I was working in Semiconductors we used a fluorocarbon liquid in a heated fish tank first. If bubbles come out you have a "gross" leak. After that we put a whole bunch of parts in a 5 gallon paint pot and pressurized it with He and let them soak. Then a small number of parts were put into the Veeco He leak tester and it was pumped down to a vacuum and we looked for leaks. The problems are: 1. The first fluorocarbon test is very important since a gross (very large hole) will pass the He leak test. Think of a small can with no lid at all. 2. A leak may be small enough to pass the fluorocarbon test yet be big enough so that by the time it gets put into the leak tester and the pump has had time to pull a vacuum, it's been emptied. i.e. it passes both tests but is really a very leaky part. If your CSAC parts were leak tested I expect they used the above procedure, but with some added details such as the exact fluorocarbon, it's temperature, time observed for bubbles, pressure in the paint pot, soak time, maximum time between depressurizing the paint pot and active He leak detection is working. You might ask for the leak test procedure they used. AFAICR all of the parts I worked with were sealed in the clean room atmosphere. I don't remember sealing under Nitrogen or some other atmosphere. So the pressure after sealing will be near the clear room pressure at the time of seal. Maybe more different if the sealing process heats the part. It would be interesting to try testing a CASC in a pressurized He environment. But the result for a hermetic unit would be no effect. For a "Gross" leak or one of the above very leaky parts you would see something if this He problem is real. To check that you might be able to get a leak test reject that's leaky. -- Have Fun, Brooke Clarke https://www.PRC68.com http://www.end2partygovernment.com/2012Issues.html axioms: 1. The extent to which you can fix or improve something will be limited by how well you understand how it works. 2. Everybody, with no exceptions, holds false beliefs. Original Message There was discussion last October about the very tiny MEMS oscillators failing from He leaking in. By now, there's several videos online showing folks taking that MEMS oscillator and putting it in a chamber and demonstrating the failure. So here's something interesting - There are a remarkable number of places with high atmospheric helium concentrations. And it causes a variety of mystery failures. The one of interest here is that helium can leak into a physics package with Rb or Cs, and that changes a) the total pressure (which causes line broadening, apparently) and b) the thermal conductivity of the vacuum. The latter is of some concern to me, since I have some CSAC devices in space that may have been exposed to a helium rich environment during storage. The failure mode on a CSAC is that more heater power is needed to keep the vapor pressure up, due to increased heat loss through the "not as good a vacuum" in the physics package. Has anyone on the list ever had a CSAC in a He-rich environment? Noticed any performance differences? I've asked Microsemi - their first response was that it's not something they tested for and that the leak rate is very low. I suppose it's probably in a hermetic can (which are *tested* with Helium leak tests) Jim ___ 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.
Re: [time-nuts] Li Ion Battery for HP 5065A
Alternatively, buy a suitably spec'ed BMS PCB from your favourite online parts site and populate it with 18650 batteries recycled from "dead" laptop battery packs. Total cost will be in the double digits. On 9/03/19 11:14 AM, Bob kb8tq wrote: Hi For 100 to 120 AH at 13.4V you will pay in the $900 to $1000 range (delivered) for the RV batteries with built in BMS. Capacity / price / current sale deal vary a bit manufacturer to manufacturer. Warranty also varies from <1 year to 10 years ….. ___ 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.
Re: [time-nuts] Li Ion Battery for HP 5065A
On 3/8/19 1:41 PM, ew via time-nuts wrote: A123 7Ah "brick" LiFePO4 who is the vendor?Bert Kehrren Here's one source https://www.buya123products.com/goodsdetail.php?i=1 ALM12V7 is what we were using, and yowza, the price went up $265 each.. Amazon has them for $140 which is closer to what we were paying.. Although ours were orange and black. More like this: https://www.amazon.ca/A123-Systems-ALM-12V7-B/dp/B008VVO6LE ___ 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] Helium leaks
There was discussion last October about the very tiny MEMS oscillators failing from He leaking in. By now, there's several videos online showing folks taking that MEMS oscillator and putting it in a chamber and demonstrating the failure. So here's something interesting - There are a remarkable number of places with high atmospheric helium concentrations. And it causes a variety of mystery failures. The one of interest here is that helium can leak into a physics package with Rb or Cs, and that changes a) the total pressure (which causes line broadening, apparently) and b) the thermal conductivity of the vacuum. The latter is of some concern to me, since I have some CSAC devices in space that may have been exposed to a helium rich environment during storage. The failure mode on a CSAC is that more heater power is needed to keep the vapor pressure up, due to increased heat loss through the "not as good a vacuum" in the physics package. Has anyone on the list ever had a CSAC in a He-rich environment? Noticed any performance differences? I've asked Microsemi - their first response was that it's not something they tested for and that the leak rate is very low. I suppose it's probably in a hermetic can (which are *tested* with Helium leak tests) Jim ___ 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] PTS160 DDS option, was Synthesized Signal Generator query
PTS have always been notoriously unhelpful to anyone aside from original purchasers. Around 15 years ago I was looking for a PTS160 manual and the UK agents were very helpful, and quite happy to request a price on my behalf, but then came back to tell me they'd been told by PTS they couldn't deal with me. When manuals did start to become available, as surplus items along with more used PTS units themselves, PTS were very quick to jump on anyone who made copies available from anything approaching a public download site. Option K, as shown in your serial number, is the 0.1Hz resolution DDS option as per the ordering information on page 30 of the current PTS catalog. This catalog is downloadable from the PTS web site and quite a useful source of information. I have one with option J, the "inferior" :-) 1Hz resolution DDS version, which the current catalog shows as an unavailable option for the PTS160 although it was in the past. Also commented in the catalog is that the PTS310 comes with DDS fitted as standard and the manual for that is available, although I'm not sure how similar the circuits might be as I tend to take an "if it ain't broke don't fix it" approach to these and so far have found all my PTS units to be very reliable.The only issues I recall have been items dislodged in transit, that DDS board for example, an obvious afterthought and a less secure fit than normal modules, was one, and a very small left over blob of solder that caused fun when it dropped into a module edge connector was another. The similar, ish, Wavetek 5120A, manual available, also uses a DDS section but again my previous comparisons focussed more on the standard modules than the DDS sections. The PTS160 and Wavetek 5120A both seem to derive from the earlier Rockland 5600 and all credit should go to PTS for greatly expanding the range, but they do seem somwhat over paranoid that someone else might jump on their bandwagon. Nigel GM8PZR I had a recent email exchange with PTS. I have a PTS 160 SK01G serial number 1A 8428. The output drops off rapidly below 70 KHz. It doesn?t match the manuals available online as it has .1Hz resolution but without the number of DM modules the manual says it should have. Instead it has a couple of DM modules and another module that apparently performs all the functions of multiple DM modules. I emailed PTS about the possibility of acquiring a manual that matches my unit and the response was: ?Sorry, don't routinely offer complimentary support or complimentary manuals. More to the point: PTS 160 has a specified lower limit of 100 KHz, no "fixing" possible to obtain outputs lower than that and not malfunctioning. If the failure is occurring when setting certain 10 KHz steps but at output frequencies above 100 KHz, we'll need to see the unit and the repair cost for a unit of that vintage is $2500. If you'd like the unit repaired, feel free to contact us, but we are not able to respond to any other inquiries on how to fix your unit.? I didn?t ask for anything ?complimentary? and would have been happy to pay a reasonable price for a manual matching my unit. Maybe explaining to them in my email that I?m a hobbyist and not a million dollar a year buyer was not a smart thing to do but I prefer to be upfront when making requests for information. If I felt the need, for $2500 I could buy a good assortment of PTS synthesizers on eBay and swap parts to my heart?s content. I?ve discovered the output amplifier rolls off quickly below 70 KHz so my unit is working correctly and I just need to switch over to a 3325B for the lower frequencies. Steve WB0DBS ___ 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.
Re: [time-nuts] Li Ion Battery for HP 5065A
On 3/8/19 1:41 PM, ew via time-nuts wrote: A123 7Ah "brick" LiFePO4 who is the vendor?Bert Kehrren A123 was the vendor (they're the mfr) I just googled, and it looks like there's now several authorized resellers of the batteries. ___ 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.
Re: [time-nuts] Li Ion Battery for HP 5065A
On 3/8/19 15:41, ew via time-nuts wrote: > A123 7Ah "brick" LiFePO4 who is the vendor?Bert Kehrren I sent this information several days ago. I guess my message never posted. Check with Bioenno Power: https://bioennopower.com This may be a drop-in replacement: https://bioennopower.com/collections/12v-series-lifepo4-batteries/products/12v-8ah-lfp-battery-abs-sealed-black-case -- Brian Lloyd 706 Flightline Spring Branch, TX 78070 +1.210.802.8359 ___ 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.
Re: [time-nuts] Li Ion Battery for HP 5065A
Hi For 100 to 120 AH at 13.4V you will pay in the $900 to $1000 range (delivered) for the RV batteries with built in BMS. Capacity / price / current sale deal vary a bit manufacturer to manufacturer. Warranty also varies from <1 year to 10 years ….. Bob > On Mar 8, 2019, at 2:32 PM, jimlux wrote: > > On 3/8/19 5:38 AM, Bob kb8tq wrote: >> Hi >> If you are headed into a “cost is no object” sort of battery backup bank for >> the lab / shelter / cave >> there are some interesting options out there. The RV world is very slowly >> waking up to the fact that >> big heavy lead acid batteries may not be ideal. For a ghastly amount of >> money, you can now get >> 12V 100AH “drop in” (no they are not drop in) Lithiums with fully integrated >> BMS systems in them. >> They *appear* to be safe and come with cute things like 10 year warranties . >> Be aware that you >> can buy a nice 5065 on eBay for what a couple of them will set you back ….. > > I've used the A123 7Ah "brick" LiFePO4 that replace the standard Lead Acid - > they weigh a LOT less, and cost a LOT more ($100 vs <$10) - They're pretty > nifty devices. As you note internal battery management, built in (easily > replaceable) 30A fuse, etc. > > They weigh about 850g (vs 2.6 kg) and work well at low temperatures (-20C) > > One peculiarity is that if you discharge them below minimum voltage, they > cutoff and put out nothing. You have to put a charging voltage on them to > turn them back on. This fouls up some "smart" battery chargers which use > the "discharged" battery voltage to tell them that there's a battery > connected. So we always had our smart chargers for day to day use, but had a > couple wall wart trickle chargers around to turn the battery back on. > > 100 Ah would set you back well over a kilobuck. But, you would be able to > lift it without you going over the OSHA 55lb/25kg "one person lift" limit. > > > > >> In return for your massive cash outlay, you get a battery that does not >> outgas or have the need >> to be watered along with the plants. It has a much flatter discharge voltage >> curve than a lead acid. >> Their peak current vs voltage generally is better than a lead acid. The BMS >> may impact this if it >> is an issue in your setup. They also is a *lot* lighter / smaller for the >> same amount of useful >> capacity. The built in BMS *should* take care of all of the fiddly little >> issues that might burn the >> house down. Lots to like other than the absolutely giant hole in the wallet >> …. >> Bob > > ___ > 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.
Re: [time-nuts] Li Ion Battery for HP 5065A
A123 7Ah "brick" LiFePO4 who is the vendor?Bert Kehrren In a message dated 3/8/2019 4:03:53 PM Eastern Standard Time, jim...@earthlink.net writes: On 3/8/19 5:38 AM, Bob kb8tq wrote: > Hi > > If you are headed into a “cost is no object” sort of battery backup bank for > the lab / shelter / cave > there are some interesting options out there. The RV world is very slowly > waking up to the fact that > big heavy lead acid batteries may not be ideal. For a ghastly amount of > money, you can now get > 12V 100AH “drop in” (no they are not drop in) Lithiums with fully integrated > BMS systems in them. > They *appear* to be safe and come with cute things like 10 year warranties . > Be aware that you > can buy a nice 5065 on eBay for what a couple of them will set you back ….. > I've used the A123 7Ah "brick" LiFePO4 that replace the standard Lead Acid - they weigh a LOT less, and cost a LOT more ($100 vs <$10) - They're pretty nifty devices. As you note internal battery management, built in (easily replaceable) 30A fuse, etc. They weigh about 850g (vs 2.6 kg) and work well at low temperatures (-20C) One peculiarity is that if you discharge them below minimum voltage, they cutoff and put out nothing. You have to put a charging voltage on them to turn them back on. This fouls up some "smart" battery chargers which use the "discharged" battery voltage to tell them that there's a battery connected. So we always had our smart chargers for day to day use, but had a couple wall wart trickle chargers around to turn the battery back on. 100 Ah would set you back well over a kilobuck. But, you would be able to lift it without you going over the OSHA 55lb/25kg "one person lift" limit. > In return for your massive cash outlay, you get a battery that does not > outgas or have the need > to be watered along with the plants. It has a much flatter discharge voltage > curve than a lead acid. > Their peak current vs voltage generally is better than a lead acid. The BMS > may impact this if it > is an issue in your setup. They also is a *lot* lighter / smaller for the > same amount of useful > capacity. The built in BMS *should* take care of all of the fiddly little > issues that might burn the > house down. Lots to like other than the absolutely giant hole in the wallet …. > > Bob ___ 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.
Re: [time-nuts] PRS-10 Warm-up Time, Calibrating/Adjusting, and long-term poweron
> A PRS10 with a long shelf life will need more than 10 months (not days !) to > get its final drift. Its dépends of the homogeneity of the gas mixture > (Rb85,87 and krypton) in the cell and a long non running time affects the > mixture. What's going on there? Why/how does the mixture change? How does the mixture effect the frequency? If that is significant, how do they make the mixture at the factory accurately enough? Or is it small so they just tune around it? -- These are my opinions. I hate spam. ___ 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.
Re: [time-nuts] Li Ion Battery for HP 5065A
On 3/8/19 5:38 AM, Bob kb8tq wrote: Hi If you are headed into a “cost is no object” sort of battery backup bank for the lab / shelter / cave there are some interesting options out there. The RV world is very slowly waking up to the fact that big heavy lead acid batteries may not be ideal. For a ghastly amount of money, you can now get 12V 100AH “drop in” (no they are not drop in) Lithiums with fully integrated BMS systems in them. They *appear* to be safe and come with cute things like 10 year warranties . Be aware that you can buy a nice 5065 on eBay for what a couple of them will set you back ….. I've used the A123 7Ah "brick" LiFePO4 that replace the standard Lead Acid - they weigh a LOT less, and cost a LOT more ($100 vs <$10) - They're pretty nifty devices. As you note internal battery management, built in (easily replaceable) 30A fuse, etc. They weigh about 850g (vs 2.6 kg) and work well at low temperatures (-20C) One peculiarity is that if you discharge them below minimum voltage, they cutoff and put out nothing. You have to put a charging voltage on them to turn them back on. This fouls up some "smart" battery chargers which use the "discharged" battery voltage to tell them that there's a battery connected. So we always had our smart chargers for day to day use, but had a couple wall wart trickle chargers around to turn the battery back on. 100 Ah would set you back well over a kilobuck. But, you would be able to lift it without you going over the OSHA 55lb/25kg "one person lift" limit. In return for your massive cash outlay, you get a battery that does not outgas or have the need to be watered along with the plants. It has a much flatter discharge voltage curve than a lead acid. Their peak current vs voltage generally is better than a lead acid. The BMS may impact this if it is an issue in your setup. They also is a *lot* lighter / smaller for the same amount of useful capacity. The built in BMS *should* take care of all of the fiddly little issues that might burn the house down. Lots to like other than the absolutely giant hole in the wallet …. Bob ___ 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.
Re: [time-nuts] PRS-10 Warm-up Time, Calibrating/Adjusting, and long-term poweron
A PRS10 with a long shelf life will need more than 10 months (not days !) to get its final drift. Its dépends of the homogeneity of the gas mixture (Rb85,87 and krypton) in the cell and a long non running time affects the mixture. After the end of this warm up period, adjustement is time consuming as the drift is parabolic and the top of the parabole tends to flatten with the successive adjustements. You can get 1 or 2 x 10^-11 and the retrace is in order of this magnitude after a couple of days without power. At this magnitude of adjustement you have to look at the barometric pressure to avoid false adjustements but the effect is little compared with the 5065A whose tube is much bigger (and with less noise...). The 5065A is a very good barometer but a little bit costly.. On Fri, 3/8/19, Attila Kinali wrote: Subject: Re: [time-nuts] PRS-10 Warm-up Time, Calibrating/Adjusting, and long-term poweron To: "Discussion of precise time and frequency measurement" Date: Friday, March 8, 2019, 4:45 PM On Fri, 8 Mar 2019 06:31:48 -0600 Dana Whitlow wrote: > The point here is that there are apparently a number of warm up drift > mechanisms operating, some of which take days to sensibly settle down. Longer. I know of one measurement, where the Rb had a kind of stable drift until it suddenly switched to another slope quite suddenly (within a few days) about half a year after power up. The aging mechanisms of Rb vapor cell standards are many and not all of them are well understood, much less controlled. Compared to that, an OCXO has "only" thermal stability of the oven, strain relaxation of the holder/crystal and deposition/removal of contaminants on the crystal surface. Ok, there are a couple more, but these three are the main contributors for most OCXO out there. While for the Rb vapor cell standard I could name you half a dozen just like that and I am far from being an expert on these. For those interested, John Vig wrote a couple of papers on the aging of OCXO in the 80s and 90s. The topic of Rb vapor cell aging is a lot more messy and I don't know whether there is any good paper that reviews the main contributors. Attila Kinali -- It is upon moral qualities that a society is ultimately founded. All the prosperity and technological sophistication in the world is of no use without that foundation. -- Miss Matheson, The Diamond Age, Neal Stephenson ___ 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.
Re: [time-nuts] PRS-10 Warm-up Time, Calibrating/Adjusting, and long-term poweron
今日は On Fri, 8 Mar 2019 14:09:20 + (UTC) Taka Kamiya via time-nuts wrote: > Why? Because nature of GPSDO and Rb, time constant is set to 2 to 3 hours. > (still experimenting) It takes few cycles of this to lock and stabilize. In > short, you'll be safe if you wait 24 to 48 hours. Rb modules are relatively > cheap. I really don't see a need to baby it. There are techniques to cut the "first lock time" down quite a bit. Most of them involve either switching of all the long time constant parts of the control loop or switching between different configurations (ie different multiplicative constants or even different topologies). The working principle of all is, that once you are reasonably close in frequency/phase, your long-time-constant loop will not have a large difference to work with and its internal state converges quickly to something close of what it should be. One very simple approach (which not always works) is to decompose your PI controller into a P and I part, and disable on startup the I part. Wait until the P part has gotten the error to something stable (not neccesarily small) then switch on the I term, with its internal state initialized to zero. A more sophisticated variant of this, uses an I part with a smaller time constant first to reduce the residual error, then estimates from its internal state the state of the real I part and switches over to that. Analysis of these dynamic loops can be a bit cumbersome and I recomend to read a good textbook on this topic before attempting to do something like this, as it's very easy to shot your foot. Attila Kinali -- It is upon moral qualities that a society is ultimately founded. All the prosperity and technological sophistication in the world is of no use without that foundation. -- Miss Matheson, The Diamond Age, Neal Stephenson ___ 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.
Re: [time-nuts] Li Ion Battery for HP 5065A
Hi If you are headed into a “cost is no object” sort of battery backup bank for the lab / shelter / cave there are some interesting options out there. The RV world is very slowly waking up to the fact that big heavy lead acid batteries may not be ideal. For a ghastly amount of money, you can now get 12V 100AH “drop in” (no they are not drop in) Lithiums with fully integrated BMS systems in them. They *appear* to be safe and come with cute things like 10 year warranties . Be aware that you can buy a nice 5065 on eBay for what a couple of them will set you back ….. In return for your massive cash outlay, you get a battery that does not outgas or have the need to be watered along with the plants. It has a much flatter discharge voltage curve than a lead acid. Their peak current vs voltage generally is better than a lead acid. The BMS may impact this if it is an issue in your setup. They also is a *lot* lighter / smaller for the same amount of useful capacity. The built in BMS *should* take care of all of the fiddly little issues that might burn the house down. Lots to like other than the absolutely giant hole in the wallet …. Bob > On Mar 8, 2019, at 6:43 AM, ew via time-nuts wrote: > > For my frequency stand alone setup opposite the rest of the lab I have a 100 > A 12V AGM/Inverter/Resonsnt Transformer that will power the setup for 10 > hours, but like you I like remove the HP 5065A powered up. Did consider a > similar system for the HP 5061B but have not and most likely will not touch > it.I am concerned about fire but I have more than 10 in one form or the other > Li Ion batteries in the house. The Battery is inside the frame that comes > with the unit. Starting with a quality product, slow charging and dual max > voltage control and dual low voltage shut out risk is very low. Changing the > Zener in the 65 reduces the output from 33V to 29.5V. The 65 cut out of 21.5V > is perfect for 7 batteries. Charging will be close to C/20. Most problems > out there seem to be do to over charge and temperature rise. Multiple tests > will be done with the pack outside the unit to allow close monitoring.The > main reason for my posting is the pile of junk batteries and finding a > reliable source.in the US. > Bert Kehren > In a message dated 3/7/2019 8:24:09 PM Eastern Standard Time, jlt...@att.net > writes: > > Bert, > > I'm interested in your quest. > > I'm interested in batteries for not only the 5065A but also the 5061A and B. > I was thinking of an SLA for the 5061's. I like the idea of being able to > move the units without having to also move a separate battery backup system > simultaneously. > > What have you come up with and how have you addressed the potential for > catastrophic failure of a Lithium Ion battery? > > Hope all is well. > > Joe > > -Original Message- > From: time-nuts [mailto:time-nuts-boun...@lists.febo.com] On Behalf Of ew via > time-nuts > Sent: Thursday, March 07, 2019 3:37 PM > To: time-nuts@lists.febo.com > Cc: ew > Subject: [time-nuts] Li Ion Battery for HP 5065A > > > > Having recently acquired a HP 5065A with clock I decided to put a battery in > it. My choice is 5000 mA Lithium Ion. Having in the past very good experience > with a Florida vendor, was first choice. Sadly he is going out of business. > 90+% out there is junk, have 26650s with 1800 mA. Last week finally located a > reliable vendor, purchased seven 21700 Samsung B50s, reasonable price. 21700 > is a better fit in the 50 X 65 X175 mm battery frame. After extensive dialog > with vapah.inc and bench tests of all seven 4800 to 5200 mA, I am convinced > that I found in the US a very viable source. No commercial or any other > interest, now my only problem is how to get rid of the other junk. > > > Bert Kehren > ___ > 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. > > ___ > 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.
Re: [time-nuts] PRS-10 Warm-up Time, Calibrating/Adjusting, and long-term poweron
On Fri, 8 Mar 2019 06:31:48 -0600 Dana Whitlow wrote: > The point here is that there are apparently a number of warm up drift > mechanisms operating, some of which take days to sensibly settle down. Longer. I know of one measurement, where the Rb had a kind of stable drift until it suddenly switched to another slope quite suddenly (within a few days) about half a year after power up. The aging mechanisms of Rb vapor cell standards are many and not all of them are well understood, much less controlled. Compared to that, an OCXO has "only" thermal stability of the oven, strain relaxation of the holder/crystal and deposition/removal of contaminants on the crystal surface. Ok, there are a couple more, but these three are the main contributors for most OCXO out there. While for the Rb vapor cell standard I could name you half a dozen just like that and I am far from being an expert on these. For those interested, John Vig wrote a couple of papers on the aging of OCXO in the 80s and 90s. The topic of Rb vapor cell aging is a lot more messy and I don't know whether there is any good paper that reviews the main contributors. Attila Kinali -- It is upon moral qualities that a society is ultimately founded. All the prosperity and technological sophistication in the world is of no use without that foundation. -- Miss Matheson, The Diamond Age, Neal Stephenson ___ 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.
Re: [time-nuts] PRS-10 Warm-up Time, Calibrating/Adjusting, and long-term poweron
Hi > On Mar 8, 2019, at 7:47 AM, Attila Kinali wrote: > > On Fri, 8 Mar 2019 01:18:45 -0700 > "Forrest Christian (List Account)" wrote: > >> 1) Assuming the PRS-10 has been off for a long time, how long should I >> plan on leaving this on for the 10Mhz to stabilize? I see the >> longest warmup time on the spec-sheet is 7 minutes - although this >> seems a lot shorter than I'd likely use in real life, I'm also not >> sure if there's much benefit to an excessively longer warmup time >> (like days), would like opinions on this. > > The warm-up time is from "I switched it on" to "there is a 10MHz signal > and it's 'stable'". I.e. at latest after 7 minutes you should be able > to use the ouptut of the PRS10. But keep in mind that the stable-after-warm-up > is not tha same as stable-for-a-time-nut. A Rb vapor cell standard has > a retrace (ie change of frequency after being switched on, for details see > John Vig's tutorial) of several weeks to a few months, depending on the > exact construction of the Rb cell, how long it has been in use and how > long it has been off. > > >> 2) Longer-term I'd like to use the 1PPS output from a Trimble >> Thunderbolt to calibrate the PRS10 and adjust if necessary just to >> trim out any aging drift on the PRS10. Initially I thought I was >> going to discipline the PRS10 on a continual basis with the >> Thunderbolt using the PPS input on the PRS10, but I've recently >> realized that leaving the PRS10 on permanently might not be the best >> option (see Question 3). So I'm looking for opinions on how to keep >> the PRS10 calibrated/adjusted. I.E. trim with the trimmer, adjust >> using digital commands, etc. > > Switching it on and off several times a month would be worse in > terms of longevity than having it running continuously. The vapor > cell itself is usually run between 60°C and 100°C and the Rb lamp > usually between 120°C and 170°C. As you can imagine, power cycling > gives a huge thermal strain on all the components. The inner construction > of the PRS10 is not optimized for power cycling but thermal insulation > of the sensitive components (see e.g. http://time.kinali.ch/Rb/PRS10/ ) > > So I would rather feed the PPS to the PRS10 directly and let itself > do the work. This will also give you an optimized control loop for > the performance of the PRS10 without you having to go through the > process of desiging and optimizing the loop. > > >> 3) As implied in #2, I was originally planning on leaving the PRS10 on >> a continuous basis. I've read a couple of things which imply that >> there is little benefit to doing so, and that every hour it's on >> consumes the lamp life. Assuming I only need the highly stable PRS10 >> source every few months for things like jitter measurements on 1PPS >> sources, is there any benefit to leaving the PRS10 on? > > If you want to do just jitter measurement, then I wouldn't use a Rb standard > but a stable OCXO instead. At averaging times below 1-10s an OCXO will beat > any Rb standard, even one that has an OCXO like the PRS10 (admittedly, it's > not a high quality OCXO but it's one none-the-less). An OCXO has a shorter > warm-up time (usually 2-3 minutes until stable, usually less than a day > until time-nuts-stable, less than a month until nutty-time-nut-stable). > > I personally, would use an OCXO as reference to the TICC (or TICCs?) > and use the PRS10 as an additional input to the TICC. This way you > can do a multi-way comparison between the GPSDOs and the Rb, removing > out the (in-)stability of the reference OCXO. > Putting some dimensions on this: A “telecom” Rb should be in the 0.01 ppb at one second (ADEV) range. It should improve by sqrt(tau) so at 100 seconds it will be at 0.001 ppb. It should improve some past that. Counting on 0.0001 ppb at 10,000 seconds …. not so much. A cheap / small OCXO may be at the same 0.01 ppb at 1 second level. An OCXO does not have a “predictable” improvement rate. You may have the same at 100 seconds as at 1 second. A very good (but maybe cheap … who knows …) OCXO could get you to 0.001 ppb at 1 second. You also could buy a few dozen to get one that actually does that. Testing could be involved to sort them out. Both the Rb and the OCXO have temperature stability specs on them. What those numbers are may be unknown on a surplus item. The “best case” claimed temperature stability on a telecom Rb is often better than the “best case” stability on your cheap OCXO. Indeed there are (rare) OCXO’s out there that get down to 0.0001 ppb at 1 second and hang in there out to 1,000 seconds. Finding one at all can be tough. Finding one cheap … you would have to be very lucky. Working out that you *do* have one will involve testing. Bob > > Beside those comments, you have not told us at what kind of performance > you are aiming at. There is a huge difference whether you need 1e-10 or > 1e-13 and whether you need it at 1s, 1ks or even 100ks averaging
Re: [time-nuts] Synthesized Signal Generator query
I had a recent email exchange with PTS. I have a PTS 160 SK01G serial number 1A 8428. The output drops off rapidly below 70 KHz. It doesn’t match the manuals available online as it has .1Hz resolution but without the number of DM modules the manual says it should have. Instead it has a couple of DM modules and another module that apparently performs all the functions of multiple DM modules. I emailed PTS about the possibility of acquiring a manual that matches my unit and the response was: “Sorry, don't routinely offer complimentary support or complimentary manuals. More to the point: PTS 160 has a specified lower limit of 100 KHz, no "fixing" possible to obtain outputs lower than that and not malfunctioning. If the failure is occurring when setting certain 10 KHz steps but at output frequencies above 100 KHz, we'll need to see the unit and the repair cost for a unit of that vintage is $2500. If you'd like the unit repaired, feel free to contact us, but we are not able to respond to any other inquiries on how to fix your unit.“ I didn’t ask for anything “complimentary” and would have been happy to pay a reasonable price for a manual matching my unit. Maybe explaining to them in my email that I’m a hobbyist and not a million dollar a year buyer was not a smart thing to do but I prefer to be upfront when making requests for information. If I felt the need, for $2500 I could buy a good assortment of PTS synthesizers on eBay and swap parts to my heart’s content. I’ve discovered the output amplifier rolls off quickly below 70 KHz so my unit is working correctly and I just need to switch over to a 3325B for the lower frequencies. Steve WB0DBS > On Mar 7, 2019, at 8:59 PM, John Ackermann N8UR wrote: > > A couple of comments about the PTS units... > > While the potential noise floor is very low (depending on the quality of the > reference oscillator), there can be significant spurs depending on how many > non-zero digits you have dialed in. With the analog multiply and mix > architecture, the more digit stages are in use, the more spurs you get above > the low noise floor. > > The lower frequency units tend to have better noise than the ones with higher > frequency ranges. The PTS X10, 040, and 160 models are the quietest if you > can live with their upper frequency limits (10, 40, and 160 MHz respectively). > > There's also one very tricksie version out there that is particularly > interesting for time-nuts -- the PTS250/SX51 where the SX51 option is a > switchable divider that turns a 250 MHz synthesizer with 1 Hz resolution into > a 25 MHZ synthesizer with 0.1 Hz resolution, and a significant phase noise > improvement. Its noise floor is around -145 dBc/Hz, while the other units > are in the -125 to -135 range. > > I have a bunch of measurements of PTS boxen at > https://febo.com/pages/pts_synth/ > > (And, I'm getting ready to sell a few of the too-many PTS boxes in my lab, > including an SX51... look out for a notice in the next week or so.) > > John > > >> On 3/7/19 7:15 PM, Alex Pummer wrote: >> that is a relative low noise synthesizer >> Programmed Test Sources PTS 160 Frequency Synthesizer >> 73 >> Alex >>> On 3/7/2019 11:04 AM, Richard (Rick) Karlquist wrote: >>> >>> On 3/7/2019 8:56 AM, Didier Juges wrote: The king of low close-in noise are the HP8662 (990MHz) and HP8663 (2GHz?) by about 20dB at 1kHz compared to the 8644A Didier KO4BB >>> >>> When I worked at Agilent, my lab had a half dozen HP8662's and some 63's. >>> They were not useful for any kind of high performance clock requirement, >>> unless we divided them down with, for example, a Centellax (now Microchip) >>> divide by 8 to 511 eval board. That was SOP in those days. >>> >>> If you just want 100 MHz, there are inexpensive 100 MHz VCXO's >>> (about $25 at D/K or Mouser) that will blow the doors off of >>> an HP signal generator. You can phase lock them to a 10 MHz OCXO >>> if necessary. Besides 100 MHz, there are various other frequencies >>> available. See Crystek and Abracon, etc. These VCXO's put out >>> CMOS logic signals, so you have to convert sine to square. >>> >>> Rick N6RK >>> >>> ___ >>> 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. >>> >>> --- >>> This email has been checked for viruses by AVG. >>> https://www.avg.com >> ___ >> 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 >
Re: [time-nuts] PRS-10 Warm-up Time, Calibrating/Adjusting, and long-term poweron
I am experimenting with exactly the same thing. PRS-10 with Thunderbolt. PRS-10 takes about a day to stabilize. When physics lock happens, it has limited stability - which is mentioned in manual. Before I calibrated, I waited for 2 days. These movements are visible if you feed GPSDO into channel 1 of scope and set a trigger on it, and feed PRS-10 output to channel 2. For thunderbolt GPSDO, I am using a telecom unit, Nortel GPSTM modified with 1 pps output. PRS-10 can take this input and lock, but it takes 1 to 2 hours to lock up. I've tried 3 different GPSDO and they were all the same. When it locks on, it is still not stable. Why? Because nature of GPSDO and Rb, time constant is set to 2 to 3 hours. (still experimenting) It takes few cycles of this to lock and stabilize. In short, you'll be safe if you wait 24 to 48 hours. Rb modules are relatively cheap. I really don't see a need to baby it. --- (Mr.) Taka Kamiya I'm stuck in a wormhole Hello, worms! On Friday, March 8, 2019, 4:00:34 AM EST, Forrest Christian (List Account) wrote: Hopefully you'll all grace me with a few answers to a beginner time-nut question or two. I have a PRS-10 I've never used other than to power it on with a recently-acquired heatsink and verify that it seems to operate correctly and that the operational parameters don't seem out of tolerance. I would like to use this in the near future as a 10Mhz reference for a TAPR TICC which I'd like to use to measure the jitter performance of the PPS output of various consumer GPS receivers, the goal being to end up with a jitter histogram. So three interrelated questions: 1) Assuming the PRS-10 has been off for a long time, how long should I plan on leaving this on for the 10Mhz to stabilize? I see the longest warmup time on the spec-sheet is 7 minutes - although this seems a lot shorter than I'd likely use in real life, I'm also not sure if there's much benefit to an excessively longer warmup time (like days), would like opinions on this. 2) Longer-term I'd like to use the 1PPS output from a Trimble Thunderbolt to calibrate the PRS10 and adjust if necessary just to trim out any aging drift on the PRS10. Initially I thought I was going to discipline the PRS10 on a continual basis with the Thunderbolt using the PPS input on the PRS10, but I've recently realized that leaving the PRS10 on permanently might not be the best option (see Question 3). So I'm looking for opinions on how to keep the PRS10 calibrated/adjusted. I.E. trim with the trimmer, adjust using digital commands, etc. 3) As implied in #2, I was originally planning on leaving the PRS10 on a continuous basis. I've read a couple of things which imply that there is little benefit to doing so, and that every hour it's on consumes the lamp life. Assuming I only need the highly stable PRS10 source every few months for things like jitter measurements on 1PPS sources, is there any benefit to leaving the PRS10 on? -- - Forrest ___ 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.
Re: [time-nuts] PRS-10 Warm-up Time, Calibrating/Adjusting, and long-term poweron
Keep in mind that the 7 min "warmup time" of the PRS-10 is jut the time for the unit to get the physics package close enough to final temperature for the dithering loop to lock to the atomic transition. But based on measurements of current drawn by the oven(s), it takes more like an hour for the ovens to settle down very well. My own experiments with a well-used "telecom mod" PRS-10 suggest that it takes my unit more like 3 or 4 days to really settle down to its background frequency drift rate. This rate is specified as something like "< 5E-11 per month", which is frankly pretty awful. Mine seems to be better than spec, more like 2E-11 per month (frequency increasing over time). The point here is that there are apparently a number of warm up drift mechanisms operating, some of which take days to sensibly settle down. I've been wondering about the issue of whether it's best to operate a PRS-10 only at times of need, or continuously, with respect to life. I posed the question direct;y to SRS, and they claim that it is better to leave it running all the time. My own "algorithm" has become "leave it on all the time" when I'm around and even remotely active with time-nuttery, but shut it down when I'm away on vacation. This is mostly out of concern for something going wrong with the power supply and burning the house down. Lightning storms are one such risk, for example. DanaK8YUM On Fri, Mar 8, 2019 at 3:00 AM Forrest Christian (List Account) < li...@packetflux.com> wrote: > Hopefully you'll all grace me with a few answers to a beginner > time-nut question or two. > > I have a PRS-10 I've never used other than to power it on with a > recently-acquired heatsink and verify that it seems to operate > correctly and that the operational parameters don't seem out of > tolerance. I would like to use this in the near future as a 10Mhz > reference for a TAPR TICC which I'd like to use to measure the jitter > performance of the PPS output of various consumer GPS receivers, the > goal being to end up with a jitter histogram. > > So three interrelated questions: > > 1) Assuming the PRS-10 has been off for a long time, how long should I > plan on leaving this on for the 10Mhz to stabilize? I see the > longest warmup time on the spec-sheet is 7 minutes - although this > seems a lot shorter than I'd likely use in real life, I'm also not > sure if there's much benefit to an excessively longer warmup time > (like days), would like opinions on this. > > 2) Longer-term I'd like to use the 1PPS output from a Trimble > Thunderbolt to calibrate the PRS10 and adjust if necessary just to > trim out any aging drift on the PRS10. Initially I thought I was > going to discipline the PRS10 on a continual basis with the > Thunderbolt using the PPS input on the PRS10, but I've recently > realized that leaving the PRS10 on permanently might not be the best > option (see Question 3). So I'm looking for opinions on how to keep > the PRS10 calibrated/adjusted. I.E. trim with the trimmer, adjust > using digital commands, etc. > > 3) As implied in #2, I was originally planning on leaving the PRS10 on > a continuous basis. I've read a couple of things which imply that > there is little benefit to doing so, and that every hour it's on > consumes the lamp life. Assuming I only need the highly stable PRS10 > source every few months for things like jitter measurements on 1PPS > sources, is there any benefit to leaving the PRS10 on? > > -- > - Forrest > > ___ > 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.
Re: [time-nuts] PRS-10 Warm-up Time, Calibrating/Adjusting, and long-term poweron
On Fri, 8 Mar 2019 01:18:45 -0700 "Forrest Christian (List Account)" wrote: > 1) Assuming the PRS-10 has been off for a long time, how long should I > plan on leaving this on for the 10Mhz to stabilize? I see the > longest warmup time on the spec-sheet is 7 minutes - although this > seems a lot shorter than I'd likely use in real life, I'm also not > sure if there's much benefit to an excessively longer warmup time > (like days), would like opinions on this. The warm-up time is from "I switched it on" to "there is a 10MHz signal and it's 'stable'". I.e. at latest after 7 minutes you should be able to use the ouptut of the PRS10. But keep in mind that the stable-after-warm-up is not tha same as stable-for-a-time-nut. A Rb vapor cell standard has a retrace (ie change of frequency after being switched on, for details see John Vig's tutorial) of several weeks to a few months, depending on the exact construction of the Rb cell, how long it has been in use and how long it has been off. > 2) Longer-term I'd like to use the 1PPS output from a Trimble > Thunderbolt to calibrate the PRS10 and adjust if necessary just to > trim out any aging drift on the PRS10. Initially I thought I was > going to discipline the PRS10 on a continual basis with the > Thunderbolt using the PPS input on the PRS10, but I've recently > realized that leaving the PRS10 on permanently might not be the best > option (see Question 3). So I'm looking for opinions on how to keep > the PRS10 calibrated/adjusted. I.E. trim with the trimmer, adjust > using digital commands, etc. Switching it on and off several times a month would be worse in terms of longevity than having it running continuously. The vapor cell itself is usually run between 60°C and 100°C and the Rb lamp usually between 120°C and 170°C. As you can imagine, power cycling gives a huge thermal strain on all the components. The inner construction of the PRS10 is not optimized for power cycling but thermal insulation of the sensitive components (see e.g. http://time.kinali.ch/Rb/PRS10/ ) So I would rather feed the PPS to the PRS10 directly and let itself do the work. This will also give you an optimized control loop for the performance of the PRS10 without you having to go through the process of desiging and optimizing the loop. > 3) As implied in #2, I was originally planning on leaving the PRS10 on > a continuous basis. I've read a couple of things which imply that > there is little benefit to doing so, and that every hour it's on > consumes the lamp life. Assuming I only need the highly stable PRS10 > source every few months for things like jitter measurements on 1PPS > sources, is there any benefit to leaving the PRS10 on? If you want to do just jitter measurement, then I wouldn't use a Rb standard but a stable OCXO instead. At averaging times below 1-10s an OCXO will beat any Rb standard, even one that has an OCXO like the PRS10 (admittedly, it's not a high quality OCXO but it's one none-the-less). An OCXO has a shorter warm-up time (usually 2-3 minutes until stable, usually less than a day until time-nuts-stable, less than a month until nutty-time-nut-stable). I personally, would use an OCXO as reference to the TICC (or TICCs?) and use the PRS10 as an additional input to the TICC. This way you can do a multi-way comparison between the GPSDOs and the Rb, removing out the (in-)stability of the reference OCXO. Beside those comments, you have not told us at what kind of performance you are aiming at. There is a huge difference whether you need 1e-10 or 1e-13 and whether you need it at 1s, 1ks or even 100ks averaging times. Attila Kinali -- It is upon moral qualities that a society is ultimately founded. All the prosperity and technological sophistication in the world is of no use without that foundation. -- Miss Matheson, The Diamond Age, Neal Stephenson ___ 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.
Re: [time-nuts] Li Ion Battery for HP 5065A
For my frequency stand alone setup opposite the rest of the lab I have a 100 A 12V AGM/Inverter/Resonsnt Transformer that will power the setup for 10 hours, but like you I like remove the HP 5065A powered up. Did consider a similar system for the HP 5061B but have not and most likely will not touch it.I am concerned about fire but I have more than 10 in one form or the other Li Ion batteries in the house. The Battery is inside the frame that comes with the unit. Starting with a quality product, slow charging and dual max voltage control and dual low voltage shut out risk is very low. Changing the Zener in the 65 reduces the output from 33V to 29.5V. The 65 cut out of 21.5V is perfect for 7 batteries. Charging will be close to C/20. Most problems out there seem to be do to over charge and temperature rise. Multiple tests will be done with the pack outside the unit to allow close monitoring.The main reason for my posting is the pile of junk batteries and finding a reliable source.in the US. Bert Kehren In a message dated 3/7/2019 8:24:09 PM Eastern Standard Time, jlt...@att.net writes: Bert, I'm interested in your quest. I'm interested in batteries for not only the 5065A but also the 5061A and B. I was thinking of an SLA for the 5061's. I like the idea of being able to move the units without having to also move a separate battery backup system simultaneously. What have you come up with and how have you addressed the potential for catastrophic failure of a Lithium Ion battery? Hope all is well. Joe -Original Message- From: time-nuts [mailto:time-nuts-boun...@lists.febo.com] On Behalf Of ew via time-nuts Sent: Thursday, March 07, 2019 3:37 PM To: time-nuts@lists.febo.com Cc: ew Subject: [time-nuts] Li Ion Battery for HP 5065A Having recently acquired a HP 5065A with clock I decided to put a battery in it. My choice is 5000 mA Lithium Ion. Having in the past very good experience with a Florida vendor, was first choice. Sadly he is going out of business. 90+% out there is junk, have 26650s with 1800 mA. Last week finally located a reliable vendor, purchased seven 21700 Samsung B50s, reasonable price. 21700 is a better fit in the 50 X 65 X175 mm battery frame. After extensive dialog with vapah.inc and bench tests of all seven 4800 to 5200 mA, I am convinced that I found in the US a very viable source. No commercial or any other interest, now my only problem is how to get rid of the other junk. Bert Kehren ___ 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. ___ 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.
Re: [time-nuts] PRS-10 Warm-up Time, Calibrating/Adjusting, and long-term poweron
> 1) Assuming the PRS-10 has been off for a long time, how long should I plan > on leaving this on for the 10Mhz to stabilize? I see the longest warmup > time on the spec-sheet is 7 minutes - although this seems a lot shorter than > I'd likely use in real life, I'm also not sure if there's much benefit to an > excessively longer warmup time (like days), would like opinions on this. Run the experiment. Collect some data from your GPS/PPS signals. Assume the GPS is correct and back compute the PRS-10 frequency. After you get everything sorted out, turn the PRS-10 off for a day, then collect data when you turn it back on and collect more data. After it has warmed up, the frequency will be stable. Look on your graph back toward the turnon time. Where can you see that the frequency differs from the stable value? It's warmed up a bit past that. -- These are my opinions. I hate spam. ___ 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.
Re: [time-nuts] injection locking crystal oscillator
Thank you for all the hints. I did several experiments, but was not able to get reliable injection locking, several times the crystal jumped some 10-20Hz down, and stayed there. Think I have decided to just remove the 10MHz crystal and drive the oscillator from a external source. BR. Thomas. Den man. 4. mar. 2019 kl. 18:41 skrev ed breya : > > In this case, it appears what you want is choice of two 10 MHz reference > sources, and not any frequency conversion. Instead of injection locking, > why not just switch between one or the other? It's quite simple to > externally drive the built-in oscillator in most ICs. You can make the > circuits however necessary to disable the crystal, and connect the > external drive, manually, or automatically - it doesn't take a lot. Then > there will be no issue of possible signal complications associated with > injection locking. > > Ed > > ___ > 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. -- With Best regards, Thomas S. Knutsen. Please avoid sending me Word or PowerPoint attachments. ___ 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.
Re: [time-nuts] Synthesized Signal Generator query
On 8/3/19 1:19 am, Don@True-Cal wrote: > Hi Jim, > The 100K to 3G frequency range of the 8664A is what I'm looking for as a > general signal source. The low phase noise needed will mostly be under > 100MHz for work on clock, trigger and timing circuits. Thanks for the reply, If you're willing to split the job, the Stanford Research CG635 is a nice unit for clock work. Especially if you build your own pods for more unusual output needs (I built some for an LVCMOS circuit I'm working on) https://thinksrs.com/products/cg635.html ___ 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.
