Re: [time-nuts] EFOS Maser turns 34!

In message <8ee9c792-a2f6-402d-9d07-f8929f656...@gmail.com>, John Ponsonby writ es: > It turns out that the resonant frequency of the cavity is > much more critically dependent on its diameter than on its length. Copper has a quite high temperature expansion, so could you servo

Re: [time-nuts] Line Voltage - USA

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[time-nuts] Tom's PICDiv?

Hi all, I was wondering if anyone makes a nice, complete unit from one of Tom's PICDivs; preferably with an external 10MHz input, a 10MHz output and a 1PPS output?  It would be nice if it also accepted a 1PPS in to sync the PIC's output to an external 1PPS source, but that's not a necessity. 

Re: [time-nuts] Line Voltage - USA

That sounds like a dangerous idea to me. Lightning arrestors at service entrances are designed to crowbar only for a cycle or so. As mentioned earlier in this thread, residential distribution in the US nearly always consists of a center-tapped balanced feed with the center tap grounded. If you

Re: [time-nuts] Temperature (environmental) sensors

Right on the page at adafruit there is a downloads link. This gets you to software read data from the board. It uses SPI Use one of those $3 arduino nanos to talk spi to the sensor and USB to a computer. The linked software does that > On Jan 4, 2017, at 11:32 AM, Dan Kemppainen

Re: [time-nuts] Temperature (environmental) sensors

I have C code (for the 8051) that is simply the translation of what's in the app note. It does temperature and humidity but not the barometric pressure (no double precision float on that compiler). Works exactly as advertised. I have two. You can see one in action here:

Re: [time-nuts] Line Voltage - USA

Wonder if these cases could be used on social media to create enough fear that there would be a market for AC crowbars capable of blowing line/pole transformer HV fuses? There's a few hits with Google, mostly for DC crowbars. Too bad relays are so slow. Bill Hawkins -Original Message-

Re: [time-nuts] New stuff in my Tindie store

> On Dec 26, 2016, at 7:40 PM, Nick Sayer via time-nuts > wrote: > > > The second one will be up next week, and it’s a simple GPS clock. The listing for the clock is live now: https://www.tindie.com/products/nsayer/gps-clock/

Re: [time-nuts] σ vs s in ADEV

Hi Attila, The plain ADEV calculation is essentially a measure of unexpected or unwanted drift in frequency; which is the 1st difference of frequency error; the 2nd difference of phase error; the 3rd difference in clock time itself. When measuring the quality of a clock, the key idea is that

Re: [time-nuts] WWVB Simulator

Not all PC audio hardware includes such a low high frequency cutoff. http://www.clarisonus.com/Research%20Reports/RR001-SoundCardEval/RR001-PCsoundCards.html Based on the above review, the following cards which are still available have a response that extends significantly above 60kHz:

Re: [time-nuts] WWVB Simulator

time-nuts@febo.com said: > A PC can certainly generate a lot of frequencies. But if you want to use the > audio channels at 60KHz there is a little problem. There is a brick wall > filter in the audio channel set at about 25 KHz. The filters I'm familiar with in audio gear scale with the

Re: [time-nuts] WWVB Simulator

A PC can certainly generate a lot of frequencies. But if you want to use the audio channels at 60KHz there is a little problem. There is a brick wall filter in the audio channel set at about 25 KHz. Now I could set up the audio to output 15 KHz I and Q and mix it (quadrature mixer) with 45

Re: [time-nuts] WWVB Simulator

Here is some nice work which was done for DCF77, Its not the same as WWVB, but worth to have a look how it was done. http://endorphino.de/projects/electronics/timemanipulator/index_en.html On 2017-01-04 14:29, paul swed wrote: Simon Like you I tend to like hardware. But today complete

Re: [time-nuts] σ vs s in ADEV

Hi Attila, On 01/04/2017 09:12 PM, Attila Kinali wrote: Hi, A small detail caught my eye, when reading a paper that informally introduced ADEV. In statistics, when calculating a variance over a sample of a population the square-sum is divided by (n-1)(denoted by s in statistics) instead of (n)

[time-nuts] σ vs s in ADEV

Hi, A small detail caught my eye, when reading a paper that informally introduced ADEV. In statistics, when calculating a variance over a sample of a population the square-sum is divided by (n-1)(denoted by s in statistics) instead of (n) (denoted by σ) in order to account for a small bias the

Re: [time-nuts] Temperature (environmental) sensors

Hi All, Just ordered a few of these BME280 sensor boards. Also ordered a FTDI C232HM cable to try to SPI or to bit-bang data from the board directly to the PC. If a PIC or similar is required, does anyone on the list have 16Bit PIC code (pic24/dsPIC) C code for reading these BME280 sensors

Re: [time-nuts] WWVB Simulator

Simon Like you I tend to like hardware. But today complete micros are so cheap and powerful they make life easy. Heck a bit to complex use 2 or 3. I like to follow the "Get-er-done" philosophy. That said search the time-nuts archive for the wwvb cheatn d-psk-r. It knows how to create the bpsk

Re: [time-nuts] Line Voltage - USA

HAHAHAHAHAHA. No, -Original Message- From: time-nuts [mailto:time-nuts-boun...@febo.com] On Behalf Of Jeremy Nichols Sent: Tuesday, January 3, 2017 11:48 PM To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] Line Voltage - USA Did the utility replace

Re: [time-nuts] Line Voltage - USA

The electric company in OKC repaired a pole problem at my parents house there a few years back. Somehow they managed to hook up the 240 across a single leg of the 120. Fried most of the electrical stuff in the house and caused enough damage to the house to require a complete rewiring.

Re: [time-nuts] Datum GPSDO up and running

How to know if your 10MHz reference is accurate?If you happen you have a "known-good" 10MHz reference you compare your new one to the old one.But lacking and "old one" and any other sophisticated time interval counters you can get a two channel oscilloscope and put your 10MHz signal on

Re: [time-nuts] Datum GPSDO up and running

On the image from LH, it says "no data from COM port". You probably need to do some tweaks to make it works. May be USB2SERIAL is picky. Also it worth to check the COM port settings. I have similar StarLockII which works ok with current LH. The only concern is device itself. For some

Re: [time-nuts] Line Voltage - USA

Hi David. I've been told that in Canada the residential supply voltage in a neighbourhood is often set to account for the voltage drop in typical residential branch circuits. The last time the supply voltage in my home was checked it read 125 volts from each "service pole" to neutral or 250

Re: [time-nuts] EFOS Maser turns 34!

Re: EFOS Maser turns 34! In a hydrogen maser the hydrogen atoms have to be confined in a storage-bulb within which the oscillating RF magnetic field is all in-phase. The storage-bulb has to be made from fused quartz for mechanical stability and for very low dielectric loss. The bulb

Re: [time-nuts] Line Voltage - USA

On 4 January 2017 at 14:25, Dr. David Kirkby (Kirkby Microwave Ltd) < drkir...@kirkbymicrowave.co.uk> wrote: > > I just phoned Tektronix and they want £160 (GBP) + VAT to calibrate this > 6000 count handheld DMM. Ouch. I will not bother with that. > Sorry, 60,000 touch - 4 3/4 digits.

Re: [time-nuts] Line Voltage - USA

Dr. David Kirkby Ph.D CEng MIET Kirkby Microwave Ltd Registered office: Stokes Hall Lodge, Burnham Rd, Althorne, Essex, CM3 6DT, UK. Registered in England and Wales, company number 08914892. http://www.kirkbymicrowave.co.uk/ Tel: 07910 441670 / +44 7910 441670 (0900 to 2100 GMT only please) On 4

Re: [time-nuts] Line Voltage - USA

Time to call your supply co. Dave -Original Message- From: time-nuts [mailto:time-nuts-boun...@febo.com] On Behalf Of Dr. David Kirkby (Kirkby Microwave Ltd) Sent: 04 January 2017 13:42 To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] Line Voltage - USA

Re: [time-nuts] Line Voltage - USA

On 4 January 2017 at 09:34, Poul-Henning Kamp wrote: > > > >Do you have a reference to this +6%? I've heard from various sources that > >the UK is 230 -6%/+10%. If the EU dictates otherwise, then I'm certainly > >over the 6% limit. I may or may not be over the 10%

Re: [time-nuts] Line Voltage - USA

Hi > On Jan 4, 2017, at 3:42 AM, Hal Murray wrote: > >> Did the utility replace the damaged equipment? > > A friend lived in a building when the city crew working on a transformer put > 440 on the line. It blew out all the electronics in 12 condos - mostly TVs. > I

Re: [time-nuts] Line Voltage - USA

> How much trouble do hams have with their insurance companies? Typically very little if you have a rider to cover it. Costs a few $ a year Had my basement flood a number of years back and take out a few k worth of vintage computer gear. Not a problem. Covered to replacement cost. I have a

Re: [time-nuts] Line Voltage - USA

I think you meant : In 240V countries it was -10%/+6%. In 220V countries it was -6%/+10% Cheers Dave -Original Message- From: time-nuts [mailto:time-nuts-boun...@febo.com] On Behalf Of Poul-Henning Kamp Sent: 04 January 2017 09:34 To: Discussion of precise time and frequency

Re: [time-nuts] FE-5650A option 58 tuning word for 10 MHz output

Hello Mathias, I did mis-speak. You're correct that only 32 bits (8 hex digits) are used to program the DDS chip. As Mark points out they store a 64 bit number and only use 56 bits but he does not elaborate on what is done with the bits beyond 32. Also, after reviewing my comment on the

Re: [time-nuts] FE-5650A option 58 tuning word for 10 MHz output

Hoi Mathias! On Tue, 03 Jan 2017 17:55:32 +0100 Mathias Weyland wrote: > On 2017-01-02 12:18, Attila Kinali wrote: > > May I ask what you want to achieve? Resp. what you need a 10MHz > > reference for? > > I've always been wondering about those devices, I guess out of pure

Re: [time-nuts] Temperature (environmental) sensors

I like the Bosch BME280 conneced to a Raspberry PI. https://learn.adafruit.com/adafruit-bme280-humidity-barometric-pressure-temperature-sensor-breakout/pinouts https://github.com/adafruit/Adafruit_Python_BME280/blob/master/README.md -- Björn Some performance plots are

Re: [time-nuts] Line Voltage - USA

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Re: [time-nuts] Observations of NTP during the leap second

Deirdre O'Byrne wrote: > My setup is a raspberry pi running Linux 4.1.19 and ntpd version 4.2.6p5. > It's being fed a PPS signal from a GPS receiver, and also checks the time > against the ntp pool. > > For the second starting at 23:59:58.0 UTC, NTP was reporting second number > 0xdc12c4fe, and

Re: [time-nuts] Line Voltage - USA

> Did the utility replace the damaged equipment? A friend lived in a building when the city crew working on a transformer put 440 on the line. It blew out all the electronics in 12 condos - mostly TVs. I think toasters and refrigerators were OK. There wasn't any question that the city was