Re: [time-nuts] NCOCXO anyone?

2016-07-24 Thread James Flynn
Richard (Rick) Karlquist writes: > The last thing you want in an oven is a lot of > added thermal overhead, especially in a double oven > where you already fighting against running out of > temperature range. If you want to ovenize everything > but the kitchen sink, put it in it's own oven that

Re: [time-nuts] NCOCXO anyone?

2016-07-24 Thread James Flynn
Hal Murray writes: > That still leaves the temperature quirks of the DAC and amplifiers. > > Has anybody put the DAC and all of the analog stuff inside the oven? Seems > like an obvious idea so somebody has probably patented it. > I am using a 5 MHz custom built design which has everything

Re: [time-nuts] HP5065A environmental sensitivities

2016-05-18 Thread James Flynn
writes: > I also have a weather station at 6 km distance away, which records barometric pressure at time intervals of > 10 minutes. Out from these measurements, I divided > my phase measurements into 10 minute intervals, calculated the 10 min average frequencies and made a > linear regression

Re: [time-nuts] What is "accuracy"? (newbie timenut, hi folks!)

2016-05-05 Thread James Flynn
Belinda, It is often good to ask such questions. So, please do not apologize. Accuracy is defined as how close a claimed parameter of a device or system (frequency, time, etc.) is to a standard. This claim has to be supported by measurements made to a certain precision, (there's that other w

Re: [time-nuts] When does NIST change to DST?

2016-03-13 Thread James Flynn
writes: > > I noticed that NIST, at http://nist.time.gov/ , is still sending standard time. When do they change? > > John WA4WDL > > As of 1849Z it was reporting DST. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to http

Re: [time-nuts] WWVB format change in 2012

2016-02-28 Thread James Flynn
le the proof-of-concept system is not being used for a refclock for NTP, it is able to keep time as described above and FREQUENCY to the under 1 E-10 range. I am still working to improve that and hope to verify it in a way directly traceable to NIST. James Flynn California State Univer

Re: [time-nuts] Trimble Thunderbolt error

2016-02-14 Thread James Flynn
Rob S. writes: > > Around 1/2 an hour ago ( I wasn't in front of mine when it happened ) at > roughly 00:45 UTC the Mates went into "holdover" mode and reported "no > Sats". I have just checked mine and it is reporting the same.. > At about 0045 Z 14FEB16 my Navman TU60 (surplus), which I run

Re: [time-nuts] Possible GPS Interference test - false alarm

2015-10-04 Thread James Flynn
James Flynn writes: > > I am away from experiment at moment, but what I could check remotely > indicated everything was running hot, straight and normal. > > I will check it again when I get back and put up data. > > I have not seen this before but was not runni

Re: [time-nuts] Possible GPS Interference test

2015-09-30 Thread James Flynn
Hal Murray writes: > > What sort of gear did that? Was it a GPSDO that went into holdover? Has it > gone into holdover at other times? > I am running a proof of constant test bed comparing time/transfer method using another medium with simple GPS time receiver. I have a disciplined dou

[time-nuts] Possible GPS Interference test

2015-09-29 Thread James Flynn
I recorded apparent anomalous activity on the GPS signal received near Los Angeles from about 0200Z to 0500Z 30 Sept. The 1PPS received signal shifted by -2E-10 in frequency (5 minute averages). There is a notice on the GPS website about possible interference today (29 Sept) through 30 Sept in

Re: [time-nuts] Z380XA The saga of the aging 10811

2015-09-25 Thread James Flynn
Bob Benward writes: > > Continuing this discussion, I have included a PDF showing the past 30days of > EFC. Amazingly, the drift has reversed direction! Anyone have any insights > into this behavior? Each data point represents 10 seconds. > I have found that three things can cause this be

Re: [time-nuts] Timepod Phase Noise Measurements and 3 corner hat

2015-08-30 Thread James Flynn
Martyn Smith writes: > MEASUREMENT TECHNIQUE > > We have three sources close in frequency (within 1 x 10E-8 of each other). > > Two sources are connected to the Ch0 and Ch 2 inputs of the timepod, the > unit under test to the ref input. > > According to John, the result will be the actual p

Re: [time-nuts] Know thy components

2015-08-07 Thread James Flynn
Hal Murray writes: > > Also the carbon composition resistor drifted with time at elevated > > temperature. > > I assume the drift is slow enough so that any any control loop will easily > track it. Actually, "ageing" is a better word than "drift". After the major change in resistance due to

[time-nuts] Know thy components

2015-08-06 Thread James Flynn
In the world of time nuts, little things matter. Nanoseconds are an eternity. We rip our hair out (if we have any left) over 1E-11 errors, weep over phase noise and shriek about Allen deviations, modified or otherwise. The question is: just where are the little things? If you are new at this,

Re: [time-nuts] Leap second results: WWVB

2015-07-01 Thread James Flynn
Scott Newell writes: > > My linux parallel port WWVB 'scope got a bit confused at the leap second: > > I have coded a WWVB receiver according to the published standard. It is all homebrew with an embedded processor and disciplined OXCO. I did not do any display shots (didn't think anyone wo