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