The Night Mail

[Tony_S]

2 hours ago, bbishop said:

I used to receive a wrist watch as a Christmas present every year and it was broke by twelfth night.  Then I found out that I have a magnetic personality.  

My father couldn’t wear a wrist watch either. They just stopped. He had a pocket watch. When he was about 60 he was given an inexpensive Sekonda and that seemed to work well.

I didn’t wear a watch after I stopped work but started again when we went on cruise holidays as I didn’t want to miss coaches when on day trips . I have a plastic body and strap  watch that charges its battery in sunlight. It was also very cheap. It does keep time well too. 

[Happy Hippo]

27 minutes ago, jamie92208 said:

For an old groaner like that we should have some sort of ground attack missile the seeks out Hippos from the rear, they would obviously have a large target.

 

Jamie

It's called a torpedo, and not a liquorice one either!!

[Happy Hippo]

18 minutes ago, Tony_S said:

I have a plastic body and strap  (on?)

And tonight dear readers, Tony is.....................................Action Man

Edited August 11, 2020 by Happy Hippo

[Tony_S]

46 minutes ago, Happy Hippo said:

And tonight dear readers, Tony is.....................................Action Man

Minimal movement is advisable here today. The only action is swatting mosquitos. 

[The Johnster]

4 hours ago, jamie92208 said:

For an old groaner like that we should have some sort of ground attack missile the seeks out Hippos from the rear, they would obviously have a large target.

My mum used to want a poetic justice missile that she could fire from her car at drivers who'd offended her in some way.  The concept was that the missile would not cause any harm, but make the engine cut out at the next set of traffic lights where there was a decent backup behind the victim, or similar.

 

I am of course a bloke, and wanted real missiles...

[Stubby47]

5 hours ago, The Johnster said:

 

I am of course a bloke, and wanted real missiles...

 

You probably need to speak to Aston Martin...

[Happy Hippo]

There was a bit of thunder and lightning here last night.

 

Of course the accompanying rain put the spoilers on it after we had spent some time watering parts of the garden less than two hours beforehand!

 

I am not sure what is on the cards this morning, perhaps some weeding of the veg plot before it gets too hot might be a plan.

 

I have been offered the plans and some castings of an LBSC Mollyette.

 

This is a gauge 0 live steam version of a 3F tank loco.  How close to scale it is remains to be seen as some of LBSC's designs were a bit fluid in the scale department.

 

Possibly it might be a plan to get an etched body kit and use it for a cosmetic shell for the extra detailing:  Conversely, it could be built as a bit of nostalgia in true 1930's style.

 

If I built it in S7, I could take it up to Hunt Towers.

 

Scorchio!

[Stubby47]

For the umpteenth year in a row, last night's Peresid Meteor showers were obscured by a full cloud cover....

[Dave Hunt]

7 hours ago, The Johnster said:

My mum used to want a poetic justice missile that she could fire from her car at drivers who'd offended her in some way.  The concept was that the missile would not cause any harm, but make the engine cut out at the next set of traffic lights where there was a decent backup behind the victim, or similar.

 

I am of course a bloke, and wanted real missiles...

 

I used to carry a full complement of phaser missiles that would instantly evaporate the offending car and its cockwomble driver. The firing control was a thumb press on the steering wheel rim. For lorries I could select multiple firings. Then I got past youth and just settled for bad language and teeth grinding.

 

Have a good day all. Forecast to reach 35 degrees where I am at present near Ellesmere.

 

Dave

[TheQ]

17 hours ago, Compound2632 said:

 

Linked either to a national time-signal, possibly the UK one, MSF, broadcast from Anthorn, Cumbria or for a product sold throughout Europe more likely the German one, DCF-77, broadcast from both Frankfurt and Anthorn, or to the GPS time signal. In all these cases, the transmitted signal is at several removes from an atomic clock.

 

The GPS signal is traceable back, via the satellites, to the ensemble of 60 commercial caesium atomic beam clocks at the United States Naval Observatory in Washington DC. I've been there, many years ago. My host was the head of their primary frequency standard development group, a most charming and un-military character with a surname of Swedish origin and parents living in Great Yarmouth. In one of the rooms full of serried ranks of HP ceasium clocks, he pointed out the one that he had, with great difficulty, managed to persuade his superiors to allow him to rotate through 90 degrees, just to check that there wasn't a N-S vs E-W frequency shift - such as might be induced by magnetic field, for instance. 

 

The MSF and DCF-77 signals are derived from hydrogen masers - although based on an energy transition in the hydrogen atom, these are not true atomic clocks as there are slowly-changing environmental effects that mean that the true hydrogen frequency is not obtained. They do, however, provide a very stable frequency - it's only after several days that the drift in frequency becomes a problem.

 

Data from everybody's national timescale is submitted to the International Beaureau of Weights and Measures (BIPM), just outside Paris. The data is combined to produce an after-the-event timescale, TAI, which is offset by a whole number of seconds from UTC, which is the legally-recognised timescale in most nations. Thus the local timescales such as MSF, DCF-77, and GPS time, are approximations to UTC; if you want to know exactly what the time was, you have to look up the offset of the timescale you were using from UTC using the BIPM's Circular T, published every five days.

 

I should add that the whole thing is kept on the straight and narrow by a handful of caesium primary frequency standards at national metrology institutes around the world, such as NPL in Teddington, which provide the true frequency of the caesium transition that is used in the definition of the second in the SI units to an accuracy of around a gnat's whisker on the diameter of the Earth. That's the bit I used to be involved in - collecting gnat's whiskers.

 

The CERN laboratory at Geneva does not generate a publicly-available timescale but may well have one for the precision timing needs of its experiments; certainly large area radio telescope arrays rely on internal maser-based timescales to ensure synchronisation of signals from the telescopes in the array.

I have two GPS frequency standards a few feet from me, locked to the GPS they are accurate to 1X10^-12 , Unlocked  3X10^-10 (over 24 Hours). They are hooked up to many systems in the factory to keep them all ticking over together..

[Compound2632]

18 minutes ago, TheQ said:

I have two GPS frequency standards a few feet from me, locked to the GPS they are accurate to 1X10^-12 , Unlocked  3X10^-10 (over 24 Hours). They are hooked up to many systems in the factory to keep them all ticking over together..

 

Sounds about right. Unlocked is typical for a quartz oscillator. The GPS standard's accuracy is a dog's hair to the gnat's whisker of  the caesium primary frequency standards, which realise the definition of the SI second to getting on for 1x10^-16. The challenge now is getting that level of accuracy out of the lab and to the user.

 

[TheQ]

29 minutes ago, Compound2632 said:

 

Sounds about right. Unlocked is typical for a quartz oscillator. The GPS standard's accuracy is a dog's hair to the gnat's whisker of  the caesium primary frequency standards, which realise the definition of the SI second to getting on for 1x10^-16. The challenge now is getting that level of accuracy out of the lab and to the user.

 

Our standards are rubidium, our frequency distribution at the moment is co-ax, but is about to be replaced by fibre optic,

 

Meanwhile, 1, my little lab's replacement A/C should be delivered by Friday and installed next week,

Meanwhile 2, My steel toe capped, boots got a puncture, the left heel has just collapsed, new ones have been ordered.

Meanwhile 3, the new system I was calibrating is on hold, some cockwomble  built the UUT to Reference system cable adaptor incorrectly. So I'm measuring some shunts instead..

[Compound2632]

1 minute ago, TheQ said:

frequency distribution at the moment is co-ax, but is about to be replaced by fibre optic,

 

That's the way to do it. You'll be using rf modulation of the optical carrier. With great care, one can use the optical carrier directly to transmit a frequency over fibre with accuracy exceeding the 1x10^-16 of the caesium primary frequency standard - good for future optical frequency standards. That rather stumped the fibre optic pundits whose dictum was that the carrier transmits no information!

 

Dear me, its five years since I gave all this much thought!

 

[Happy Hippo]

I've been in the garden digging up weeds.

 

I don't think I will return to it this afternoon: Working in the garage or workshop will keep me out of the house, but it will be much cooler.

[Dave Hunt]

Note to the Q and Compound - it's about five past two here. And the best timekeeping was by Eccles, who had it writ on a piece of paper.

 

Dave

[TheQ]

Here it's 30 minute to ********* off home time , just one shunt to finish..

[Stubby47]

Already at home, 2 1/2 hours of pointless Team's meetings to go...

[TheQ]

15 minutes ago, Stubby47 said:

Already at home, 2 1/2 hours of pointless Team's meetings to go...

the joy of learning how to use microsoft teams in the morning...

[Florence Locomotive Works]

Well I present the fruits of my labors. One might notice there is no water gauge. It’s complicated story, but for now I’m just using blanking plugs. The engine has been made to look like one of those made by marklin in the last half of the 19th century, hence the shrouds over the motion. The plan was to have it belted up to a dynamo, but the engine doesn’t have enough torque to spin the one I have. The cylinder cap leaks a wee bit more than it probably should, but oh well. I will also be purchasing a Lionel gooseneck lamp to go in a hole between engine and boiler, even though there’s no dynamo to power it. Apologies for the poor video quality, YouTubes fault. 
 

stay healthy, 

 

Douglas

 

 

[The Johnster]

23 hours ago, Compound2632 said:

 

Linked either to a national time-signal, possibly the UK one, MSF, broadcast from Anthorn, Cumbria or for a product sold throughout Europe more likely the German one, DCF-77, broadcast from both Frankfurt and Anthorn, or to the GPS time signal. In all these cases, the transmitted signal is at several removes from an atomic clock.

 

The GPS signal is traceable back, via the satellites, to the ensemble of 60 commercial caesium atomic beam clocks at the United States Naval Observatory in Washington DC. I've been there, many years ago. My host was the head of their primary frequency standard development group, a most charming and un-military character with a surname of Swedish origin and parents living in Great Yarmouth. In one of the rooms full of serried ranks of HP ceasium clocks, he pointed out the one that he had, with great difficulty, managed to persuade his superiors to allow him to rotate through 90 degrees, just to check that there wasn't a N-S vs E-W frequency shift - such as might be induced by magnetic field, for instance. 

 

The MSF and DCF-77 signals are derived from hydrogen masers - although based on an energy transition in the hydrogen atom, these are not true atomic clocks as there are slowly-changing environmental effects that mean that the true hydrogen frequency is not obtained. They do, however, provide a very stable frequency - it's only after several days that the drift in frequency becomes a problem.

 

Data from everybody's national timescale is submitted to the International Beaureau of Weights and Measures (BIPM), just outside Paris. The data is combined to produce an after-the-event timescale, TAI, which is offset by a whole number of seconds from UTC, which is the legally-recognised timescale in most nations. Thus the local timescales such as MSF, DCF-77, and GPS time, are approximations to UTC; if you want to know exactly what the time was, you have to look up the offset of the timescale you were using from UTC using the BIPM's Circular T, published every five days.

 

I should add that the whole thing is kept on the straight and narrow by a handful of caesium primary frequency standards at national metrology institutes around the world, such as NPL in Teddington, which provide the true frequency of the caesium transition that is used in the definition of the second in the SI units to an accuracy of around a gnat's whisker on the diameter of the Earth. That's the bit I used to be involved in - collecting gnat's whiskers.

 

The CERN laboratory at Geneva does not generate a publicly-available timescale but may well have one for the precision timing needs of its experiments; certainly large area radio telescope arrays rely on internal maser-based timescales to ensure synchronisation of signals from the telescopes in the array.

Close enough for jazz, then...

[Compound2632]

1 minute ago, The Johnster said:

Close enough for jazz, then...

 

Timing is key.

[Happy Hippo]

54 minutes ago, Compound2632 said:

 

Timing is key.

I thought that was the essence of a good joke..........

[laurenceb]

Never trusted atomic clocks since the tim I saw two in a shop window showing totay diferent times

[Dave Hunt]

Currently monitoring the flood defences in the workshop/railway room after finding it flooded when we got home and as I write this undergoing a downpour of tropical intensity. More detail on ERs so I'll sign off now and go to see how the sandbags are getting on.

 

Dave

[Happy Hippo]

17 minutes ago, Dave Hunt said:

Currently monitoring the flood defences in the workshop/railway room after finding it flooded when we got home and as I write this undergoing a downpour of tropical intensity. More detail on ERs so I'll sign off now and go to see how the sandbags are getting on.

 

Dave

I'm sorry to hear about the flood.

 

I hope it all gets sorted out ok.