Author Topic: Antenna in atomic clock  (Read 5982 times)

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Offline fixit7Topic starter

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Re: Antenna in atomic clock
« Reply #25 on: May 03, 2019, 01:38:28 pm »
Yep, ordinary dollar store clock.

You are not funny.

Dollar stores do not sell my model.
 

Offline NivagSwerdna

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Re: Antenna in atomic clock
« Reply #26 on: May 03, 2019, 01:40:05 pm »
I am wondering whether I bought a true atomic clock.
Wonder no more... you didn't.

PS
Someone else seems to have also given this model more attention than it deserves... https://mysku.me/blog/china-stores/48540.html
 

Online PA0PBZ

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Re: Antenna in atomic clock
« Reply #27 on: May 03, 2019, 01:45:30 pm »
I have to manually set time when changing batteries. How could a radio controlled clock maintain the time if it has no power?

It doesn't, it gets the time over the radio, that is why it is called radio controlled.
« Last Edit: May 03, 2019, 01:48:13 pm by PA0PBZ »
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Online PA0PBZ

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Re: Antenna in atomic clock
« Reply #28 on: May 03, 2019, 01:46:34 pm »
Yep, ordinary dollar store clock.

You are not funny.

Dollar stores do not sell my model.

I still hope you get the idea.
Keyboard error: Press F1 to continue.
 

Offline BravoV

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Re: Antenna in atomic clock
« Reply #29 on: May 03, 2019, 02:13:16 pm »

Offline Domagoj T

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Re: Antenna in atomic clock
« Reply #30 on: May 03, 2019, 02:29:20 pm »
Are proper atomic clock even available to general public, or within purchasing power of an average civilian?
I'm not talking radio clocks, but real caesium/rubidium stuff.
 

Offline NivagSwerdna

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Re: Antenna in atomic clock
« Reply #31 on: May 03, 2019, 03:02:04 pm »
Are proper atomic clock even available to general public, or within purchasing power of an average civilian?
I'm not talking radio clocks, but real caesium/rubidium stuff.
GPS time transfer from Satellite is dirt cheap nowadays... if you can solve for position then you have already solved for time.
You will find people here, that have a Rb frequency standard or even Caesium standard I believe!... and lots of GPSDO owners.
On the whole it is easier to use someone else's standard and transfer it... e.g. Radio standards, GPS, ....
 

Offline Domagoj T

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Re: Antenna in atomic clock
« Reply #32 on: May 03, 2019, 03:21:27 pm »
That's why I ask about the non radio (actual atomic) clocks.
GPS satellites are in roughly 20 000 km orbits, so latency is at least 65 ms (more for slant range). Furthermore, while I'm pretty sure GPS sats keep correct time, the position calculation doesn't depend on the receiver getting the correct time, just that the clocks on the satellites are synced, since it's the time difference that matters for GPS.
Since GPS receivers don't have a two way communication capability, adjusting for this 65+ ms latency to get the correct time is not possible.
Frequency standards again don't need to keep time, just the beat, right?

That's why I ask if real, full blown atomic clocks are available to mere mortals. I honestly don't know and don't really have an idea for a ballpark figure.
 

Offline NivagSwerdna

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Re: Antenna in atomic clock
« Reply #33 on: May 03, 2019, 03:34:53 pm »
...the position calculation doesn't depend on the receiver getting the correct time..
To calculate the distance to the satellite requires the local time and this is solved for; basically in 4D (you need >=4 SV)
« Last Edit: May 03, 2019, 03:42:12 pm by NivagSwerdna »
 

Offline Domagoj T

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Re: Antenna in atomic clock
« Reply #34 on: May 03, 2019, 03:41:41 pm »
Only if you have an atomic clock synced with the satellite you are calculating against.
Which is what we don't have at this point.
 

Offline Richard Crowley

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Re: Antenna in atomic clock
« Reply #35 on: May 03, 2019, 03:44:43 pm »
There are many posts and discussions about "atomic" (rubidium) oscillators that are used by every cell phone tower. Many are available on Ebay, etc. which have been replaced for whatever reason.  And the laboratory-grade equipment (like the HP, etc.) is widely discussed and available to hobby-level volt-nuts. There are many videos on YouTube about these things.

There will be latency no matter what standard, source, distance etc.  But that is a different factor than accuracy, stability, etc.
 

Offline soldar

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Re: Antenna in atomic clock
« Reply #36 on: May 03, 2019, 05:02:46 pm »
I'm pretty sure its just another common cheap LCD clock, maybe cost 5 or 10 bucks.

I have bought them for a dollar at the dollar store.

Makes me think about how a throw-away dollar clock of today can keep time better than extremely expensive mechanical chronometers of just fifty years ago.

For celestial navigation purposes I have checked the rate of many cheap quartz clocks over several years and they can be incredibly stable. What is important is that the rate at which they run fast or slow is stable. Later you just correct for this when taking readings.
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Offline fixit7Topic starter

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Re: Antenna in atomic clock
« Reply #37 on: May 03, 2019, 06:12:40 pm »
I am wondering whether I bought a true atomic clock.
Wonder no more... you didn't.

PS
Someone else seems to have also given this model more attention than it deserves... https://mysku.me/blog/china-stores/48540.html

You are right.

LaCross came up with the design while others copied it. (Minus the radio controlled part.)

 

Offline fixit7Topic starter

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Re: Antenna in atomic clock
« Reply #38 on: May 03, 2019, 06:13:58 pm »
I have to manually set time when changing batteries. How could a radio controlled clock maintain the time if it has no power?

It doesn't, it gets the time over the radio, that is why it is called radio controlled.

So there are radios that do not need power? A little hard to believe.

 

Offline ruffy91

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Re: Antenna in atomic clock
« Reply #39 on: May 03, 2019, 06:29:19 pm »
I have to manually set time when changing batteries. How could a radio controlled clock maintain the time if it has no power?

It doesn't, it gets the time over the radio, that is why it is called radio controlled.

So there are radios that do not need power? A little hard to believe.
It does not maintain time without power. It does receive the time via radio after power is supplied via the battery..
This typically takes a few minutes.
 

Offline CJay

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Re: Antenna in atomic clock
« Reply #40 on: May 03, 2019, 07:24:33 pm »
2x Rb standards, at least two GPS-DO and a Cs, all sat in my workshop (I may have to admit I have a problem), so yes, atomic standards are available and in reach of the 'average' hobbyist and I'm in no way as rich as some of the guys here, everything I have bought has to be *cheap* (I've blown my entire month's pocket money on one item this month so it's packet noodles and hot water for the rest of the month now but hell, it was worth it  :-DD :-DD )

 

Offline LateLesley

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Re: Antenna in atomic clock
« Reply #41 on: May 03, 2019, 07:28:13 pm »

So there are radios that do not need power? A little hard to believe.

Actually, you CAN get radios that do not need power. They've been about since I was a kid in the 70s. There were crystal radio sets which could work with no power supply. They used the received signal to generate the supply, but it was very low power, it wasn't gonna drive speakers.

I actually just found someone who designed one, which could work with a speaker.

https://hibp.ecse.rpi.edu/~john/xtal.html

And everyone's picking on this OP over "atomic radio", give them a break, it'll be one of the time signal receiver clocks, which is tied to an atomic reference clock. thus the "atomic clock". Here in the UK its the MSF time signal, it used to be known as the rugby clock signal.

https://www.npl.co.uk/msf-signal

Other countries have their own version of this, like WWVB in USA,  DCF77 in Germany, or JJY in Japan

https://en.wikipedia.org/wiki/Radio_clock
 
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Offline AG6QR

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Re: Antenna in atomic clock
« Reply #42 on: May 03, 2019, 07:34:42 pm »
Doesn't look like there's much in the way of radio receiver in there, I'd be pretty sure it's not a radio clock but, does it set itself when you apply power or do you have to do it manually?

The MSF clocks I have flash 12:00 at first (and then 12:01, :02 etc.) until they sync for instance

I have to manually set time when changing batteries. How could a radio controlled clock maintain the time if it has no power?

It doesn't maintain the time without power.  When it powers up, it flashes 12:00, and it turns on its radio receiver to grab the time from the radio station and set itself.  This may take a couple of minutes.  If propagation is marginal, it may not work until nighttime.  In some locations, it might never work.
 

Offline windsmurf

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Re: Antenna in atomic clock
« Reply #43 on: May 03, 2019, 08:43:03 pm »
 :horse:
 
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Offline Richard Crowley

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Re: Antenna in atomic clock
« Reply #44 on: May 03, 2019, 09:06:39 pm »
Are proper atomic clock even available to general public, or within purchasing power of an average civilian?
I'm not talking radio clocks, but real caesium/rubidium stuff.
There are many Rubidium oscillators on Ebay for <$100 and some for even <$50
That gets you the frequency accuracy and stability, but not the time synchronization.
You can get time sync from GPS.  At least as close as you would ever need for private uses.
For that matter, if you are getting time sync from GPS, you don't need your own local oscillator anyway.
 

Offline hwj-d

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Re: Antenna in atomic clock
« Reply #45 on: May 03, 2019, 09:19:58 pm »
LateLesley,
you're one of the few sensible ones here in the thread  :-+
 
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Offline NivagSwerdna

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Re: Antenna in atomic clock
« Reply #46 on: May 03, 2019, 10:16:57 pm »
And everyone's picking on this OP over "atomic radio", give them a break, it'll be one of the time signal receiver clocks, which is tied to an atomic reference clock. thus the "atomic clock". Here in the UK its the MSF time signal, it used to be known as the rugby clock signal.
But it is NOT a radio-controlled clock!  |O
 

Offline radiolistener

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Re: Antenna in atomic clock
« Reply #47 on: May 04, 2019, 04:50:58 am »
So there are radios that do not need power? A little hard to believe.

Actually, you CAN get radios that do not need power. They've been about since I was a kid in the 70s. There were crystal radio sets which could work with no power supply. They used the received signal to generate the supply, but it was very low power, it wasn't gonna drive speakers.

yeah, here some examples :)
 
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Offline soldar

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Re: Antenna in atomic clock
« Reply #48 on: May 04, 2019, 09:38:17 am »
What we've got here is failure to communicate. Some men you just can't reach. https://youtu.be/452XjnaHr1A?t=12
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