Atomic Clock

[TheInterocitor]

Does anyone use "atomic clock" in Russia? My friend wants me to send a (wall) clock or (wrist) watch, I can't tell, the words are translated to the same word in Russian!

This Sharp (Japanese company) atomic clock, I got one at an auction just a couple of weeks ago, for $2. Nobody else at the auction knew what it was. They go at the Walmart for $30-$150. You put the battery in, and press the "reset" button, and the hands revolve until it gets to the correct time. The exact time. It is getting a radio signal from somewhere in the US, and the clock updates itself maybe twice a day, so it always has the correct time, to the precise second.

It is not, internally, this type of clock, but receiving the signal from a similar clock, I think:

US and Russia Researchers, Working Together, Make Most Precise Clock Ever

I wonder they have equivalent type clock in Russia, or if they can pick up signal from US?

[Hans.KK]

I wonder they have equivalent type clock in Russia, or if they can pick up signal from US?

In the most south-western part of Russian you may be able to use the German DCF77 system/signals.
On my consumer grade clock I have placed in our window facing south-west it works mostly ok, but the clock inside the same room 4 meters from the window do not work.
I worked on a professional DCF77 system some 30 years ago, it was not easy to get a stable radio signal alt all and we were located app 7-800 km from the transmitter in Germany. For a consumer grade clock it is ok to get a good signal now and them to make the clock look like it is accurate, but for a timekeeping device in a system where you are billing your customers by the 1/10 of a second you need a 100% stable time signal all the time.

The British have also a radio transmitted system (mostly to change tariff on electricity meters), but it works only in the UK, and I recall French also had a radio system to time keeping, but again, French only.

Today you would use GPS, and if you use a choke ring antenna (it also have another name I can't remember) then you can get a very prices time signal, these special antennas are huge, up to 20-30 cm in diameter for some of them, and their purpose is to filter off all kinds of reflected versions of the main signal, a reflected signal, just for a few centimetre away gives a longer travelling time for the signal and a wrong time. It is a bit crazy we are talking cm of of a total travelling distance of 20000 km.

In GSM (mobil phone systems) antenna ground systems, they use a rubidium timekeeping device as the local time source and they often have a GPS time source too, because the know the precise geographical position of the antenna and the have the GPS signal they can calculate a correction factor for that place on the earth that can be used in the neighbourhood at special GPS receivers (DGPS) to calculate a even more precise time (and position of an object) on an moving object, farmers use it, and pay a premium for the service.

The term "atomic" is there because the time source is coming from an atomic clock. https://en.wikipedia.org/wiki/Atomic_clock

[TheInterocitor]

In the most south-western part of Russian you may be able to use the German DCF77 system/signals.
On my consumer grade clock I have placed in our window facing south-west it works mostly ok, but the clock inside the same room 4 meters from the window do not work.
I worked on a professional DCF77 system some 30 years ago, it was not easy to get a stable radio signal alt all and we were located app 7-800 km from the transmitter in Germany. For a consumer grade clock it is ok to get a good signal now and them to make the clock look like it is accurate, but for a timekeeping device in a system where you are billing your customers by the 1/10 of a second you need a 100% stable time signal all the time.

The British have also a radio transmitted system (mostly to change tariff on electricity meters), but it works only in the UK, and I recall French also had a radio system to time keeping, but again, French only.

Today you would use GPS, and if you use a choke ring antenna (it also have another name I can't remember) then you can get a very prices time signal, these special antennas are huge, up to 20-30 cm in diameter for some of them, and their purpose is to filter off all kinds of reflected versions of the main signal, a reflected signal, just for a few centimetre away gives a longer travelling time for the signal and a wrong time. It is a bit crazy we are talking cm of of a total travelling distance of 20000 km.

In GSM (mobil phone systems) antenna ground systems, they use a rubidium timekeeping device as the local time source and they often have a GPS time source too, because the know the precise geographical position of the antenna and the have the GPS signal they can calculate a correction factor for that place on the earth that can be used in the neighbourhood at special GPS receivers (DGPS) to calculate a even more precise time (and position of an object) on an moving object, farmers use it, and pay a premium for the service.

The term "atomic" is there because the time source is coming from an atomic clock. https://en.wikipedia.org/wiki/Atomic_clock

The signal is traveling 300,000 kilometers/second, a few centimeters makes a big difference?

I wonder what farmers use it for?

Strange clock this one. I put the battery in and it changed the time, but it was a minute late. A couple of hours later, it made itself 3 minutes late. Then the next day, it corrected itself to synchronize with time same as computer and cell-phone time.

[Hans.KK]

The signal is traveling 300,000 kilometers/second, a few centimeters makes a big difference?

Yes, GPS is all about timing.
Consumer grade, my small USB GPS receiver out on a small hill on the fields, nothing around that flat soil, I log the position and the accuracy from the thing, all raw data and analyse it afterwards, we are all over the shop, moving 1-25 meters within seconds, and up to 100 meters for no reason, the device is just standing still nobody around, it is there for hours. Then we get a guy to come with professional gear, he puts a stick in the ground at the top of the hill, place a 30 cm round UFO there and record the position, the raw data do not change that much, a few cm that is all. Difference in price on these solutions is just a numbers of zero's and just about 10-15 times in size.
The consumer device is optimised for small size, the pro version for accurate position indication. So the apparently high precision on your GPS on your smartphone, or car's navigation system, is exactly that, apparently.
The high accuracy in the pro gear is more than a damn good antenna, it also these correction data that change with the atmospheric conditions, so these are dynamic because the atmosphere is dynamic, so in the pro gear there is also a small mobile phone that only can send and receive data, your correctional data, so it need to have access to the mobile phone network to work.
These places where this corrections data is generated is often just inside a mobile phone cell tower, and it is just software, all data it needs to work is a by product in the cell tower anyway, so it is a dead giveaway to make it into money and sell this service. And this service is also a victim in trade wars now and then, the US wanted to punish Russia for what ever reason, and ban them for selling GPS correction data in the US, and Russia did as they often do, they copied the US ban and imposed it on US company's operating in Russia, then a lot of US company's was upset, "Hi US government, we are making a shitload of money in Russia and we need these data to sell our main product, stop that silly ban on Russian company's operation in the US", and that was the end of that trade war. For those that do not know then there are two main players in GPS systems, a US and a Russian system, the EU and Japan I think are trying something but are to small to matter.

I wonder what farmers use it for?

To place your tractor with it's gear on the exact place before starting your work like spray poison all over, when you get to the end of the field you turn the tractor and run back exactly X amount of cm from the first run and you repeat this over and over and you get a perfect covering of the field with what ever shit you pollute the environment with, in this way you get the work done with minimum of expense to poison/fertiliser/seeds and maximum covering, some of the stuff that are put on the fields are crazy expansive so you can save a lot of money to do it perfectly.
Some machinery are even self-driven, so it is important that you do not plow up the road next to your fields, and at the same time you want to plow just to the edge.
We had a guy that was asleep at the wheel and did not respond fast enough to the alarm signal "You are off track" and parked a million dollar expensive toys into a stream. His only task was to turn the machine (approximately once every 60 minutes) when it reached the end of the field, the machine could only drive and steer automatically when it went pretty straight ahead, it could not turn itself, 50 meters wide and it is a bit of a task to turn it around without taking too much time, and too much nearby stuff just gets a little push of a 17 tons monster (guess who will win that fight).

Strange clock this one. I put the battery in and it changed the time, but it was a minute late. A couple of hours later, it made itself 3 minutes late. Then the next day, it corrected itself to synchronize with time same as computer and cell-phone time.

Just a case of "good enough for government work", the signal is just not the best and it comes and goes as it want's to, so what should the poor clock do? trying to keep the time when it think it know what it should be and hope for the best.
My brother have a clock where the clock, when it realise that it is showing time ahead of the real time, it correct this by spinning the pointers around until the time is correct, so if one minute ahead it start the travelling of 11 hours and 59 minutes and it takes longer time than what it was off with in the first place (the clock can't go backwards).