EEVblog #235 - Rubidium Frequency Standard

[FrozenHaxor2]

I want to build a clock with it :D

[CampKohler]

If any of you rubidiumites want to see the next level of teardown, Mike from mikeselectricstuff saw this vlog, bought one, ruined it and so proceded to destroy it for our benefit. Take a looksee at /watch?v=ymV9LwhD0W0.

[KhaledHamalawy]

love you dave , you are awesome

[davidjereb]

What a coincidence! I bought one of these just 2 months ago. I'm currently planning to put it in a tidy box and stick a linear power supply in there. I'm also thinking of dividing the frequency and giving it a PPS output.

[Nadrealis]

Dave you planning anything for your 300th? It's right around the corner at the pace you're going :)

[googacct]

If you are going to channel Bob Pease, you are going to have to grow a big bushy beard. :-)

[Nathanxiangdarby]

Awesome keep them coming....

[TheElectricnoob]

I found one of these on ebay for less than 40 bucks but its from china so im a bit weary it may be a chinese knockoff despite beeing the same model number, though it is attached to a large board that seem to be a groundplane. The auction sez 1Hz to 10MHz. I wonder how hard it would be to hook up some RS232 and control it, if an arduino could do it, like convert a pot on a adc input to a 0-255 value out the serial bus.

[solderandbeer]

Nice description - I really miss Bob Pease. 

[Afrotechmods]

Nifty! I had no idea you could get this kind of accuracy for so cheap!

[razean22]

i don't recognize any out-of-sync

[Gameboygenius]

19:50 The frequency reading is drifting horribly much. Is that a problem with the standard or the scope, you think?

[Wilfredkazoks]

The sound seems out of sync. Only slightly but enough to be distracting.

[CampKohler]

Is the heat coming from the lamp? Does the resonating chamber take this into account and that is the reason for the delay in locking? If you do do a teardown, open it right after shutdown and check everything with a IR thermometer to see which parts are at what temperature.

[EEVblog]

@CampKohler I think I mentioned that the lamp part was the hottest.

[kiyotewolf]

magic little box

[randomgarfield]

@eevblog the first 10 or so seconds, then it rights itself.

[CampKohler]

What do you think would happen if you got two and beat them together?

[envisionelec]

@CampKohler Keep it family friendly. ;)

[CampKohler]

@envisionelec You naughty boy, you! Now we know what you do for a hobby. :-)

[patrickdonovan7]

I keep clicking and nothing is happening! :-p Thanks Dave, can't wait for the next one.

[TheLaidukas]

You were so convincing that I just bought two of these. :D

[EEVblog]

@TheLaidukas I'll be sure not to spend my commission all at once! :->

[Zadster]

The "sine wave" output looks pretty awful, which won't help the signal jitter. That's kinda important for doing precision timing work. Any chance you could do a Fourier analysis of it?

[combatwombat71]

I've got a programmable one. Programmed it up to 10.0666666667MHz, to triple, to get 30.2MHz reference for my radio gear.

[SwitchingPower]

I just bought the same one on ebay for only €35 / $43 :)

[CampKohler]

@SwitchingPower Now that this video is out, will it drive the price up?

[solderandbeer]

@CampKohler I haven't done any rigorous data collecting, but it seems the price of E-bay items that Dave mentions does increase. Dave should start a service - mention your (hopefully, electronic only) item for only x dollars. (Wait, I bet X would be more than the increase. Never mind.)

[SwitchingPower]

@CampKohler I haven't seen the prices go up so far.

[TheEPROM9]

I think I am going to try and pic one of these up.

[TheXGamer969]

Hey, where's the teardown? Stop teasing me!!

[solidliqs]

This is an awesome device! I can't wait to see you build a project out of it, like a function generator! iotw, PLEASE do that!

[LukeeeeBennettPlus]

Is that a Hakko FX888 in the background? Is that what you use most frequently?

[EEVblog]

@LukeeeeBennettPlus Yes it's what I recommend to most people.

[uGateKiller]

Is it me or is the audio and video out of sync?

[atamasuzu]

@uGateKiller

no, it's utube ..., something sucks today, maybe G.W. Bush is sniffing again (Bush for president? no thanks)

[raoul4]

@uGateKiller It's you.

[Zadster]

@uGateKiller It seems to happen quite a bit on Dave's videos, if you tab away from the video and then tab back again the sync has drifted. Must be some interaction between his codec and YouTube's transcoding.

[EEVblog]

@Zadster I've never seen that, and no one else reports it. As Youtube transcodes all uploaded videos, I suspect either everyone would see it, or it's just you?

[Zadster]

@EEVblog Not sure, it seems to happen on 2 different machines, and under Firefox, Chrome or IE, and not seen it with anyone else's videos. Not reported it before because it's not a problem, moving the cursor resets the sync. No biggie.

[msylvain59]

Check eBay for vintage, military grade "Efratom" rubidium units (black cubic things), they must be made much better than these OEM things.

[mikeselectricstuff]

To clarify some slight confusion in the vid over terms for osc types :

TCXO : temperature compensated - simple analogue circuit to compensate for ambient temp

DTCXO : digitally temperature compensated - as above but potentially more accurate as can track xtal characteristic more accurately over the temp range,e.g. from a lookup table.

OCXO :ovened - holds the xtal at a fixed temperature

[superdau]

I not sure if it's completely the same inside the "physics package", but we built a setup inn a lab at uni, which could show the hyper fine structure of Rb87 gas.

There really are many of excatly the same part you have there (FE-5680A) on ebay for as low as under 30€. All coming from China though and some cheating by labeling their items "new".

[Intosia]

Good stuff!

[sabamacx]

Interesting as HELL!

[smldis]

what about jitter? I'm curious :)

[TheCrazyInventor]

That is an interesting piece of hardware. Can't wait for the teardown of this and your phillips freq counter.

[Steaphany]

Awfully simplified - who would not know that Rb87 refers to the isotope ?

Dave Magic = Physics !

Says a gal who plays with Quantum Cosmology - a great hobby ;-)

[AnnoyingVerification]

As for the thing getting warm, expect the bottom plate to be much warmer than the top cover! Typically, the datasheet calls for these things to be mounted on a heatsink. For instance the Symmetricom LPRO: "A heat sink with thermal resistance to ambient of less than 2°C/W is required for ambient of 50°C maximum."

[implor]

No teardown yet.... maybe you still uploading it ;)

[Steaphany]

Rubidium Frequency Standard = a low cost Atomic Clock

[randomgarfield]

Audio sync is japanese kung fu style! 5-6 frames I reckon.

[EEVblog]

@randomgarfield Who else is seeing sync problems? I don't see it. I am using a new video editor, so if there is an issue, this will be it.

[twmduk]

@EEVblog not seeing any sync problems here

[envisionelec]

@EEVblog I see it.

[thewii552]

@EEVblog no audio sync problems here...

[Ryantron9000]

@EEVblog I'm not. It seems fine.

[solderandbeer]

@EEVblog I'm seeing (and hearing) a bit of a sync problem here.

[TheComputerMan97]

@EEVblog Don't see much of any audio sync issues. Also, could you sometime do a behind-the-scenes of making a blog (software, camera, mic, etc.)?

[g5pw]

As a HAM, this is most interesting!

[blizniak28]

"stuff anyhow" yaaaaaa :D

[reviathon360]

Hey Dave,

I was wondering if you ever did a Sansa MP3 player tear down? Because I have one and I want the LCD, but I can't find any datasheets. Any tips?

[megasmart1337]

Nice1

[turbochargedbrick]

legend!