Antenna in atomic clock - Page 1
Forum section: electronics / beginners

author: fixit7
author_rank: Regular Contributor
timestamp: May 02, 2019, 07:47:22 pm
content: I am wondering whether I bought a true atomic clock.I took apart my clock and it does not have anything like this antenna.https://www.dropbox.com/s/lsae0sulcd1r9zr/Antenna.png?dl=0Is it supposed to have an antenna?I assume it needs one to get updated on the time from the time server.

author: Benta
author_rank: Super Contributor
timestamp: May 02, 2019, 07:57:14 pm
content: You bought a radio receiver for DCF77 and other time transmitting services. The "atomic clocks" are at the transmitter end.

author: CJay
author_rank: Super Contributor
timestamp: May 02, 2019, 08:21:25 pm
content: Why don't you post a picture of your radio clock?

author: soldar
author_rank: Super Contributor
timestamp: May 02, 2019, 08:42:57 pm
content: Quote from: Benta on May 02, 2019, 07:57:14 pmYup. I have one I bought at LIDL but it must be trying to learn German or something because it has not yet changed to summer time.Not as bad as the ones LIDL sold in the UK which could not be set to UK time, only CET. You set it to UK time and it would automatically set itself to CET. For some odd reason the brits did not like this idea and returned them.http://home.bt.com/news/uk-news/lidl-recalls-most-accurate-clock-in-the-world-because-its-stuck-on-german-time-11364031992681Quote

author: fixit7
author_rank: Regular Contributor
timestamp: May 03, 2019, 01:12:10 am
content: Quote from: CJay on May 02, 2019, 08:21:25 pmhttps://www.dropbox.com/s/zyejxytym9012ij/20190502_200905.jpg?dl=0

author: fixit7
author_rank: Regular Contributor
timestamp: May 03, 2019, 01:17:02 am
content: Quote from: Benta on May 02, 2019, 07:57:14 pmI did not buy a radio receiver. I just posted a picture of one.I took my clock apart and it has no receiver. :-)The clock has no manufacturer name on either the manual or the clock.

author: edpalmer42
author_rank: Super Contributor
timestamp: May 03, 2019, 02:20:34 am
content: Yes, there should be an antenna. Typically, it's a ferrite rod like the one in the picture that you showed.I've seen this before. There might be two models that look identical, but one has the radio receiver and the other doesn't. They could even have the same LCD - which has specific segments for the atomic clock function, but the receiver just isn't in one version. You might be able to see where the receiver connects to the main board.Ed

author: floobydust
author_rank: Super Contributor
timestamp: May 03, 2019, 02:54:40 am
content: The ferrite rod antenna is usually stuffed in the enclosure, not on the PCB. Take it apart and look.

author: fixit7
author_rank: Regular Contributor
timestamp: May 03, 2019, 03:13:06 am
content: Quote from: floobydust on May 03, 2019, 02:54:40 amI looked.No wires leaving the pcb other than to a speaker which is used for the alarm and it plays a melody whenever battery is changed.The clock time does correspond to what my phone says, so it is pretty accurate.Maybe not accurate to a few seconds, but I am happy with it.I had a leftover UPS 12 volt battery (8 Ah) that I thought would power the clock for a long time instead of using the normal 2 AA batteries.I used a buck step down converter."https://www.ebay.com/itm/DC-DC-Buck-Step-Down-Converter-Module-LM2596-Voltage-Regulator-Led-Voltmeter-M3/301724177038?epid=10003955778&hash=item464029928e:g:bAwAAOSwdsFUNdsC"The clock uses about 10 mA, but the converter uses about .2 Volt per day.

author: radiolistener
author_rank: Super Contributor
timestamp: May 03, 2019, 04:37:55 am
content: Unfortunately most of us don't trained for using telepathy and don't have magician crystal ball with magic vision to see what you're talking about. If you post photo of electronics inside your clock it will helps to say how it works.At a glance, this is just a usual crystal quartz electronic clock.

author: Richard Crowley
author_rank: Super Contributor
timestamp: May 03, 2019, 05:48:31 am
content: What leads you to think you have an "atomic clock" at all?What does the back look like? There is nothing on the front that suggests an "atomic clock".Typically there is something in the LCD display of a "lock" indicator when it is receiving WWVL (60KHz)

author: soldar
author_rank: Super Contributor
timestamp: May 03, 2019, 06:37:29 am
content: Quote from: Richard Crowley on May 03, 2019, 05:48:31 amWell, it is made with atoms. It is not only atomic but molecular also.

author: BravoV
author_rank: Super Contributor
timestamp: May 03, 2019, 07:09:09 am
content: Quote from: radiolistener on May 03, 2019, 04:37:55 amQuote from: Richard Crowley on May 03, 2019, 05:48:31 amTelepathy wise, I "sense" the OP was sort of scammed by seller maybe ?Anyway, the mandatory smileys for the clock internal photo ...

author: PA0PBZ
author_rank: Super Contributor
timestamp: May 03, 2019, 07:20:26 am
content: I think a good question would be:How did you set the time?

author: soldar
author_rank: Super Contributor
timestamp: May 03, 2019, 07:34:44 am
content: I think there is a good chance it is just a plain, regular quartz crystal clock and the question would be why the OP believes it is any kind of " atomic" clock.Decades ago, when quartz clocks were new, I did hear people use the term " atomic" to distinguish them but I believe that is not used any more.

author: windsmurf
author_rank: Frequent Contributor
timestamp: May 03, 2019, 08:03:34 am
content: The antenna's could be very tiny, like the ones found in Casio Waveceptor watches.

author: mikerj
author_rank: Super Contributor
timestamp: May 03, 2019, 08:28:13 am
content: Quote from: fixit7 on May 03, 2019, 03:13:06 am10mA is a ridiculous amount of current for a basic quartz controlled LCD clock, it should be down in the low microamps.

author: imisaac
author_rank: Regular Contributor
timestamp: May 03, 2019, 08:48:12 am
content: QuoteJust to clarify.A true rubidium or caesium based atomic clocks would also have an antenna attached in order to sync with the UTC time broadcasted by the satellites.A "clock" without antenna would represent some local oscillator for the convenience of timekeeping. It will have accuracy problem over time due to the relative drifts between your oscillator and the standards.For easy identification in the future, you could look for some glass tubes and ovens on your board if the clock is based on the atomic standards.For a serious identification, you should measure its long term frequency stability and time stability somehow and make sure that they are below 10-11.

author: BravoV
author_rank: Super Contributor
timestamp: May 03, 2019, 09:03:10 am
content: Quote from: imisaac on May 03, 2019, 08:48:12 amLooking at the OP's photo of the clock and it's size, don't think that a true atomic clock can be powered just by simple common small batteries.I'm pretty sure its just another common cheap LCD clock, maybe cost 5 or 10 bucks.

author: NivagSwerdna
author_rank: Super Contributor
timestamp: May 03, 2019, 09:20:42 am
content: Atomic clock is a very generic term... It may have a Rubidium Standard, Caesium Standard or Hydrogen Maser inside but it is difficult to tell without pictures of the insides.Looking forward to seeing some internal PCB shots.

author: fixit7
author_rank: Regular Contributor
timestamp: May 03, 2019, 10:47:49 am
content: https://www.dropbox.com/s/my1zbtzqexh3etn/RadioClock3.jpg?dl=0https://www.dropbox.com/s/o9llh4kz2lanpyc/RadioClock2.jpg?dl=0https://www.dropbox.com/s/6uvtzc1lgthhwvd/RadioClock1.jpg?dl=0

author: PA0PBZ
author_rank: Super Contributor
timestamp: May 03, 2019, 10:55:17 am
content: Yep, ordinary dollar store clock.

author: CJay
author_rank: Super Contributor
timestamp: May 03, 2019, 11:18:37 am
content: 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

author: Richard Crowley
author_rank: Super Contributor
timestamp: May 03, 2019, 12:54:06 pm
content: That is not an "atomic clock". That is an ordinary digital clock. Your photos show the little 32.769KHz "watch crystal" that is the time-keeping element.An "atomic clock" requires user-controls to establish what time zone you are in so that it knows what offset to apply from the UTC that is broadcast by WWV or CHU or DCF77 or whatever is your local source.Here is a photo of the back of my "atomic clock" just for reference....

author: fixit7
author_rank: Regular Contributor
timestamp: May 03, 2019, 01:37:14 pm
content: Quote from: CJay on May 03, 2019, 11:18:37 amI have to manually set time when changing batteries. How could a radio controlled clock maintain the time if it has no power?

author: fixit7
author_rank: Regular Contributor
timestamp: May 03, 2019, 01:38:28 pm
content: Quote from: PA0PBZ on May 03, 2019, 10:55:17 amYou are not funny.Dollar stores do not sell my model.

author: NivagSwerdna
author_rank: Super Contributor
timestamp: May 03, 2019, 01:40:05 pm
content: Quote from: fixit7 on May 02, 2019, 07:47:22 pmWonder no more... you didn't.PSSomeone else seems to have also given this model more attention than it deserves...https://mysku.me/blog/china-stores/48540.html

author: PA0PBZ
author_rank: Super Contributor
timestamp: May 03, 2019, 01:45:30 pm
content: Quote from: fixit7 on May 03, 2019, 01:37:14 pmIt doesn't, it gets the time over the radio, that is why it is called radio controlled.

author: PA0PBZ
author_rank: Super Contributor
timestamp: May 03, 2019, 01:46:34 pm
content: Quote from: fixit7 on May 03, 2019, 01:38:28 pmI still hope you get the idea.

author: BravoV
author_rank: Super Contributor
timestamp: May 03, 2019, 02:13:16 pm
content: Quote from: NivagSwerdna on May 03, 2019, 01:40:05 pmIndeed ...->Less than 4 dollars, free shippingLess than 5 dollars, free shipping too

author: Domagoj T
author_rank: Frequent Contributor
timestamp: May 03, 2019, 02:29:20 pm
content: 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.

author: NivagSwerdna
author_rank: Super Contributor
timestamp: May 03, 2019, 03:02:04 pm
content: Quote from: Domagoj T on May 03, 2019, 02:29:20 pmGPS 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, ....

author: Domagoj T
author_rank: Frequent Contributor
timestamp: May 03, 2019, 03:21:27 pm
content: 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.

author: NivagSwerdna
author_rank: Super Contributor
timestamp: May 03, 2019, 03:34:53 pm
content: Quote from: Domagoj T on May 03, 2019, 03:21:27 pmTo calculate the distance to the satellite requires the local time and this is solved for; basically in 4D (you need >=4 SV)

author: Domagoj T
author_rank: Frequent Contributor
timestamp: May 03, 2019, 03:41:41 pm
content: 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.

author: Richard Crowley
author_rank: Super Contributor
timestamp: May 03, 2019, 03:44:43 pm
content: 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.

author: soldar
author_rank: Super Contributor
timestamp: May 03, 2019, 05:02:46 pm
content: Quote from: BravoV on May 03, 2019, 09:03:10 amI 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.

author: fixit7
author_rank: Regular Contributor
timestamp: May 03, 2019, 06:12:40 pm
content: Quote from: NivagSwerdna on May 03, 2019, 01:40:05 pmYou are right.LaCross came up with the design while others copied it. (Minus the radio controlled part.)

author: fixit7
author_rank: Regular Contributor
timestamp: May 03, 2019, 06:13:58 pm
content: Quote from: PA0PBZ on May 03, 2019, 01:45:30 pmSo there are radios that do not need power? A little hard to believe.

author: ruffy91
author_rank: Regular Contributor
timestamp: May 03, 2019, 06:29:19 pm
content: Quote from: fixit7 on May 03, 2019, 06:13:58 pmIt 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.

author: CJay
author_rank: Super Contributor
timestamp: May 03, 2019, 07:24:33 pm
content: 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)

author: LateLesley
author_rank: Frequent Contributor
timestamp: May 03, 2019, 07:28:13 pm
content: Quote from: fixit7 on May 03, 2019, 06:13:58 pmActually, 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.htmlAnd 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-signalOther countries have their own version of this, like WWVB in USA, DCF77 in Germany, or JJY in Japanhttps://en.wikipedia.org/wiki/Radio_clock

author: AG6QR
author_rank: Frequent Contributor
timestamp: May 03, 2019, 07:34:42 pm
content: Quote from: fixit7 on May 03, 2019, 01:37:14 pmIt 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.

author: Richard Crowley
author_rank: Super Contributor
timestamp: May 03, 2019, 09:06:39 pm
content: Quote from: Domagoj T on May 03, 2019, 02:29:20 pmThere are many Rubidium oscillators on Ebay for <$100 and some for even <$50That 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.

author: hwj-d
author_rank: Frequent Contributor
timestamp: May 03, 2019, 09:19:58 pm
content: LateLesley,you're one of the few sensible ones here in the thread

author: NivagSwerdna
author_rank: Super Contributor
timestamp: May 03, 2019, 10:16:57 pm
content: Quote from: LateLesley on May 03, 2019, 07:28:13 pmBut it is NOT a radio-controlled clock!

author: radiolistener
author_rank: Super Contributor
timestamp: May 04, 2019, 04:50:58 am
content: Quote from: LateLesley on May 03, 2019, 07:28:13 pmyeah, here some examples

author: soldar
author_rank: Super Contributor
timestamp: May 04, 2019, 09:38:17 am
content: What we've got here is failure to communicate. Some men you just can't reach.https://youtu.be/452XjnaHr1A?t=12