Re: [time-nuts] AN/URQ-13 FE-15a oscillator question

I see a glass tape on the inner oven with writing "40.0". Thats it. Assuming C its a long way off.The flask is fine the ovens are heating to 110F. Both of them. So somethings wrong. Interesting as I peel something like caulking off the outer board I see what looks like a opamp. But its a FE house n

Re: [time-nuts] AN/URQ-13 FE-15a oscillator question

Hi If you are reading something below 60C on a dewar flask outer oven …. it is borken….. very broken. Bob > On Feb 12, 2021, at 7:25 PM, paul swed wrote: > > The temps I am reading are with a K thermocouple so pretty accurate. I had > simply slid the thermocouple into the flask on the outer e

Re: [time-nuts] The need for quartz crystals and mains frequency (was: Mains Frequency)

Hi Andy and Attila, On 2021-02-13 01:27, Attila Kinali wrote: > On Fri, 12 Feb 2021 18:23:54 + > Andy Talbot wrote: > >> Why should the microcontroller have a crystal at all? > Because you need accurate time or frequency. Often stability is issue. Depending on what you do, either or both may

[time-nuts] WWVB BPSK Atomic Clock Receiver Modules

Universal Solder has a Valentines day sale this weekend for up to 20% for members. They sell the WWVB BPSK Atomic Clock Receiver Modules and accessories for those interested. https://www.universal-solder.ca/ Cheers ___ time-nuts mailing list -- time

Re: [time-nuts] AN/URQ-13 FE-15a oscillator question

The temps I am reading are with a K thermocouple so pretty accurate. I had simply slid the thermocouple into the flask on the outer edge of the ovens.The assembly is out of the flask now and both inner and outer are heating. Will see what they do. Both seem to be heating at about the same rate. So

[time-nuts] The need for quartz crystals and mains frequency (was: Mains Frequency)

On Fri, 12 Feb 2021 18:23:54 + Andy Talbot wrote: > Why should the microcontroller have a crystal at all? Because you need accurate time or frequency. E.g.: You have a USB connected device. The USB specs say that the reference clock for the device must be accurate to 0.2% (2000ppm) under al

Re: [time-nuts] Mains Frequency

The joke in USA at that time was that the power companies adjusted their frequency by calling the local telephone company (which was ATT/Bell Telephone almost everywhere). In that era, you could call a local number and get the time. The power companies used that time number, it was joked, to adjust

Re: [time-nuts] Mains Frequency

It's still +47 seconds.Perhaps they'll correct over the weekend. Wind generation is high at the moment, contributing 13.64GW to the 34GW UK total demand (it it 22:100 as I write). Perhaps the high wind generation level is the reason for the extended high frequency session. Andy www.g4jnt.com

Re: [time-nuts] AN/URQ-13 FE-15a oscillator question

Hi According to table 1-2 in: http://www.navy-radio.com/freq/urq-eimb.pdf The URQ-9 and URQ-10 both were rated for 0 to 50C. Per: http://www.navy-radio.com/freq/urq23-MIL-T-28816.pdf The URQ

Re: [time-nuts] Mains Frequency

artgod...@gmail.com said: > Andy, what equipment do you use to monitor the cycle count ? I use a modem control signal connected to a serial port on a PC. Most OSes have code to grab a time stamp on an interrupt. The target usage was a PPS signal for timing. It works OK at 60 Hz as well as 1

Re: [time-nuts] Mains Frequency

Oh, they've moved on a long way from that. They often have mesh networked control now, using 868MHz or cell networks in some cases. On Fri, 12 Feb 2021 at 16:57, Adrian Godwin wrote: > I wouldn't be surprised to find that streetlight clocks use the same old > Sangamo or Venner electromechanical

Re: [time-nuts] Mains Frequency

at the time I grew up in Eastern Europe -- "communist time" -- they kept he clocks using the line frequency as reference -- by counting the periods during the day and week and for longer time for equal time interval the "provided" equal number of line frequency periods, as longer the time inter

Re: [time-nuts] AN/URQ-13 FE-15a oscillator question

Hi In a dewar flask OCXO, all the heat loss is out the “mouth” of the flask. There is essentially zero energy flow between the inner and outer walls via the “vacuum filled” gap between them. The net result is that if you heat a “plug” in the flask, everything past that plug will be at the same t

Re: [time-nuts] AN/URQ-13 FE-15a oscillator question

Paul, from your description, it sounds like it's not an outer and inner oven in the traditional sense, but that the extra heater is to improve things at the weak spot in the Dewar system - the opening, where the high-grade insulation is lost, and conductive things pass through. So maybe it shou

Re: [time-nuts] Mains Frequency

Mine peaked at +50s earlier today, it may have gone higher but didn't see. Now down to +44s. There may be a longer term offset, since this monitor was set arbitrarily 265.3 hours ago, and who knows what the official offset was at that point Andy www.g4jnt.com

Re: [time-nuts] Mains Frequency

It seems the Swiss are in charge of regulating the frequency of the grid in Europe. According to https://www.swissgrid.ch/en/home/operation/regulation/frequency.html European clocks are running 21.064 s fast as of this writing. As mentioned earlier trading affects the frequency. You can see

Re: [time-nuts] Mains Frequency

Why should the microcontroller have a crystal at all? Many have factory trimmed RC oscillators, typical 1% accuracy, because accurate timing for other than timekeeping is rarely needed. A minute per month is 10ppm, typical of a bog standard crystal, and given the choice of that or mains timing for

Re: [time-nuts] AN/URQ-13 FE-15a oscillator question

Well there is no doubt someone has been deep into this unit. Hint missing screws internally. But appears both heater windings are ok. So inner and outer oven has a new meaning. I typically understood this to be one oven in another oven. Think the HP CS units of old. The same in other places HP3801.

Re: [time-nuts] Mains Frequency

Streetlights now use radio control from a master, using, at least round here, a GSM type of protocol on a dedicated frequency, so every individual light can be set, at different brightness levels. And they do do this - at least on a street basis. And they monitor every light. I take the 50Hz in

Re: [time-nuts] Mains Frequency

On 2/12/21 8:23 AM, Thomas D. Erb wrote: "I would think they try to hold it over 1 day, so that mains driven clocks don't run slow or fast.? That being said, I wonder how many clocks are still being built using a synchronous motor drive? Given that all the clocks on appliances in my kitchen ha

Re: [time-nuts] Mains Frequency

The classic 70's LED clock used a 60Hz mains transformer and yes it was easy enough to for the solid state electronics count pulses derived from the low voltage secondary winding of the mains transformer. If your appliances are from the 70's or 80's yes it is very likely the LED clock is counting A

Re: [time-nuts] Mains Frequency

I wouldn't be surprised to find that streetlight clocks use the same old Sangamo or Venner electromechanical timers that they've always used, and are far more of a problem to correct than domestic clocks. Andy, what equipment do you use to monitor the cycle count ? On Fri, Feb 12, 2021 at 2:55 P

Re: [time-nuts] Allan Deviation 68-95-99 rule

Nice explanation, Magnus. Thank you. On Fri, Feb 12, 2021, 9:33 AM Magnus Danielson wrote: > Hi, > > On 2021-02-12 12:25, Simon Lewis wrote: > > Hi everyone, > > > > Novice question, but does the 1-sigma, 2-sigma, 3-sigma (68-95-99) rule > > apply to Allan and modified deviations? That is, can I

Re: [time-nuts] AN/URQ-13 FE-15a oscillator question

Yes Bob they could get hot. But the radio rooms I have been in circa 1970s were all air conditioned from destroyers to aircraft carriers. Shirt sleeve. The best place to actually be when we were down by the equator was the radio room, ET shop, CIC and radar and just maybe the Captain's stateroom. B

Re: [time-nuts] Mains Frequency

"I would think they try to hold it over 1 day, so that mains driven clocks don't run slow or fast.? That being said, I wonder how many clocks are still being built using a synchronous motor drive? Given that all the clocks on appliances in my kitchen have drifted apart, I'll bet they use their

Re: [time-nuts] AN/URQ-13 FE-15a oscillator question

Hi If it’s 105F “outdoors” that’s 40C. Military gear back in the days of the URQ10 did not live in air conditioned enclosures. It did get deployed to places with temperatures at or above that level. If it’s 40C outdoors, by the time you get to a pile of electronics gear *indoors*, a >10C rise

Re: [time-nuts] Allan Deviation 68-95-99 rule

Hi, On 2021-02-12 12:25, Simon Lewis wrote: > Hi everyone, > > Novice question, but does the 1-sigma, 2-sigma, 3-sigma (68-95-99) rule > apply to Allan and modified deviations? That is, can I say that that if my > MDEV is 1e-11 for 1s, 99% of samples fall within 3 MDEVs? I know that the > standard

Re: [time-nuts] AN/URQ-13 FE-15a oscillator question

Bob OK there is the math. and that all starts to line up. So most likely for other URQ units there will be an ambient max in the spec's. At least on the URQ10 in real life even in the hot tropics the radio room was shirt sleeve temps. But the question asked was 110 F correct as measured on the outs

Re: [time-nuts] AN/URQ-13 FE-15a oscillator question

Bad news for me. None of the military manuals states the temperatures of the inner and outer ovens. Pretty sure various HP manuals never did either. Regards Paul. On Fri, Feb 12, 2021 at 9:22 AM paul swed wrote: > Paul > This is Paul to confuse the thread. I always thought the outer was cooler >

Re: [time-nuts] AN/URQ-13 FE-15a oscillator question

Hi Indeed the outer oven (as a minimum) needs to be 5 to 10 C above the maximum ambient. If it’s not it goes out of regulation (runs away) and you loose any benefit from it. ( = it now works against you ). The inner oven as a minimum needs to be 5 to 10 C above the outer oven. Again if it is low

Re: [time-nuts] Mains Frequency

On 2/12/21 3:12 AM, Andy Talbot wrote: I maintain a real time display of mains frequency, and the cumulative timing offset from real time. It was last reset 10 days ago when we had a brief power outage (HV fault a mile or so away). Since then, for the first few days the timing discrepancy kept

Re: [time-nuts] AN/URQ-13 FE-15a oscillator question

Paul This is Paul to confuse the thread. I always thought the outer was cooler also. Its becoming clear many things I have learned over the years might be a bit off. I was thinking of looking at several other references that do have documentation urq10 and 23. See what the maintenance documents say

Re: [time-nuts] Mains Frequency

Hi Andy I recall many years ago when most of us had mains synchronous motor clocks the frequency was tweaked nationally to set the clocks right at I think 06:00 every morning. I guess since most now use quartz clocks that has been dropped.interesting! Just turn the wind down a bit will

Re: [time-nuts] Mains Frequency

IIRC the requirement used to be that it was correct averaged over 24 hours. I think the Europe wide rules go like this: 1. In the short term (seconds to hours), several mechanisms are employed that continuously try to keep the frequency as close as possible to 50. Hz, but that do no

[time-nuts] Allan Deviation 68-95-99 rule

Hi everyone, Novice question, but does the 1-sigma, 2-sigma, 3-sigma (68-95-99) rule apply to Allan and modified deviations? That is, can I say that that if my MDEV is 1e-11 for 1s, 99% of samples fall within 3 MDEVs? I know that the standard variance is the same as the ADEV for white FM, but are

[time-nuts] Mains Frequency

I maintain a real time display of mains frequency, and the cumulative timing offset from real time. It was last reset 10 days ago when we had a brief power outage (HV fault a mile or so away). Since then, for the first few days the timing discrepancy kept within plus/minus perhaps 20 seconds. B