So you see an image like this and the description “Aircraft stable oscillator” on an eBay listing for twenty pounds (about thirty bucks), what do you do? If you’re [Alecjw] you buy the thing and crack it open to find an atomic clock source inside. But he really went the distance with this one and figured out how to reconfigure the source from the way it was set up in the factory.
First off, the fact that it’s made for the aerospace industry means that the craftsmanship on it is simply fantastic. The enclosure is machined aluminum and all of the components are glued or otherwise attached to the boards to help them stand up to the high-vibrations often experienced on a plane. After quite a bit of disassembly [Alec] gets down to a black box which is labeled “Rubidium Frequency Standard”… jackpot! He had been hoping for a 10 MHz signal to use with his test equipment but when he hooked it up the source was putting out 800 kHz. With a bit more investigation he figured out how to reconfigure the support electronics to get that 10 Mhz source. We think you’re going to love reading about how he used a test crystal during the reconfiguration step.
Once he knew what he had he returned to the eBay seller and cleared out the rest of his stock.
[Thanks DIY DSP]
Very nice! i have an $150 ebay sourced 10mhz GPS controlled rubidium clock standard i put in a nice fancy case and used a few video distro cards to shove them out on to my equiptment
tho i dont think you can use them as a standard if it outputs a square wave …
“…cleared out the rest of his stock.”
Sonuva…
:P
Step 1) Find cool item.
Step 2) Confirm its worth.
Step 3) HAD post.
Step 4) Relist at higher price.
Step 5) ???
Step 6) Profit.
Step 5 is “sell.”
I’m fairly sure step 5 is just wait in this case.
Hate people who do that.
What a guy… ruining it for everyone else to make a few quid. I won’t buy one on principal. Hacking is about sharing knowledge and ideas, not fleecing other people.
Allow me to explain myself here… I bought a mysterious part with the risk of ending up with something completely useless. I then spent a lot of my time documenting it, adding value to it for anyone who buys one. Hopefully this doesn’t seem too unreasonable! Besides, I’m at college at the moment, so I have an education to pay for!
Don’t worry – the emoticon was intended to indicate that this is meant in a joking, “Curses, foiled again!” way.
Are you going to fool us by saying you “worked hard” on this hobby to find a fcking datasheet when anyone with scope and a screwdriver would do the same?
I have no words. Take a job to pay bills, not hacking opportunities. You do not deserve to be mentionned on any interesting blog.
Please fellow hackers, do not sponsor college fees for such a mron.
There are tons of rubidium standards for EUR 60-70 that outputs 10 MHz out of the box, and are much smaller.
BTW, is M0TEI a ham call?
what the fuck is wrong with you people? all over the comments on the article i see retards like yourself flaming the guy for making a bit of profit off of a project, are you really so fucking stuck up that you just have to make these nasty comments on articles about it?
Good read!
I wonder if he could check it against the NIST atomic time standard by injecting his clock into a shortwave radio tuned to WWV at 10MHz and looking for heterodyne beats. As I recall, WWV’s frequency is accurate to better than 10^-12
If he paid “pounds” for them, he might be out of WWV’s range…
Practically no such thing as “out of range” of WWV. But, if you wish to be pendantic, there are shortwave time hacks based in Europe.
this thing would need to be tunable to achieve external lock. And you can do the same with a GPS, it’s also NIST traceable.
Great writeup! The DDS chip configured with dip switches is interesting… convenient though I guess.
now that’s a hack!
No, that’s a business operation.
Can someone explain, what exactly you would use this for?
its always nice to have references in your lab … a calibrated voltage, current, resistance exc reference to make sure your stuff is up to cal … a frequency standard is no different
tho the benefits of a 10mhz reference is most good equipment will take an external 10mhz clock to not just keep all your equipment synchronized but you know quite damn well that the frequency you are measuring is DEAD on accurate
tho it has its own wacky uses .. put it on a watch and have the worlds most accurate watch, use it on an atmel and have an AVR with the frequency drift of a satellite, use it to heat your room or you can throw it at intruders!
Most accurate Arduino ever!
10mHz?
Dont be an ass you know what i mean
Um, since you want to be an ass, you wrote the abbreviation for millihertz. the correct answer is MHz, not that it really mattered. we all knew what he meant.
People who live in glass houses shouldn’t be dicks.
If I remember correctly the radioactive decay products poison the accuracy or increase the phase noise of atomic clocks over time. Might want to check how old those units are as that may be the reason why they are for sale so cheap.
But even if that is true is the decay in accuracy such that it would be a big deal? I mean the accuracy the military demands (not needs maybe, but demands) is quite different than what the average hacker would be happy with.
Oh no! 10-10 accuracy instead of 10-12! Most cheap clocks are 1 – 3%.
I’m more interested in how they us Rb as a clock source. The common isotope has a halflife of 49 billion years. The decay product isn’t a problem, it’s a stable 87Sr.
Okay, read up on the way the clock is used. It’s not detected the decay, but like quartz it’s detecting the energy given off by 87Rb when exposed to a known frequency. The long HL means there should be very little decay product that needs to be accounted for, and it probably doesn’t respond at the same frequency. Anyone want to find out how much energy is generated by 87Sr at 6 834 682 610.904 324 Hz?
And WOW, if I read that right, that source should be accurate up to a awfully high MHz, even 1 or 2 GHz, reference
EEVblog #235 – Rubidium Frequency Standard
http://www.youtube.com/watch?v=I55uLRRvLCU
Apart from this phase noise, remember that the product presented here produces a signal via a DDS followed by a crystal quartz. A DDS is not really a good frequency reference.
A trimble GPSDO would probably generate a better short term signal with a better long term stability.
Soooo, can this run an atomic bedside alarm clock? “No more excuses for being late! Your clock is powered by the energy of the Atom!”
Your clock is kept in time, but not powered by the energy of the Atom!”
Oh yes it is! Just not the Rubidium Atom(s)
Bullshit.
Out of over 9,000 excuses this only invalidates two or three.
So are you! You are a collection of atoms writing this post! :D
It was probably use don conjunction with a GPS. It’s best to use both as GPS accuracy can waiver depending on your location and the time-of-day. That way you can maintain extremely high accuracy without any variance.
Presumably the Doppler effect causes issues with GPS timing as well.
The time differences in GPS signals are exactly how GPS triangulation works, although a dedicated clock could maybe improve accuracy.
I was in the military and we used time standards that used both Rb and GPS. GPS has issues, some listed in other comments, but some were not known at the time of implementation. So, at certain times of day in combination of our position on the planet, our accuracy varied. Not wildly, but, it varied. This is the reason why the DOT installed WAAS which uses two land based DGPS stations (E/W coast) and a satellite that’s right above MO. This is actually more accurate for air travel and other related commerce. Also, the US Coastguard has installed DGPS stations all over the east and west coast. The reaosn is that even with GPS “unlocked” it is still not accurate enought to find someone in the event of an emergency. You throw in DGPS stations and you can locate someone in coastal waters, with a commercial GPS unit, within several meters.
Some things that prompted the UGS and DOT and WAAS wa sthat originaly the L1 GPS band was “spiked” by the military to reduce accuracy. The military stopped this after DGPS stations were abound as it made no sense anymore. But, the L2 is still an encrypted signal and this provides additional accuracy. But, once again, with my own personel military experience, the accuracy would drift and this is actually important as you can cross into the territorial waters of some other country. So, we had to compensate and be furthur out. Also important for GPS guided bombs, there is a “window” of time where the GPS they use is the most accurate. I’ll leave it at that.
You can use Google and look up atmospheric scintillation and GPS do find more info on GPS accuracy issues with the expansion and contraction of the atmosphere.
I think if they can compensate for General and Special Relativity (which they do) they can compensate for Doppler if that was even a problem… Which on the speed an airplane is moving at relative to the satellites is negligible. If it is necessary, I’m sure they would add a dash of math and be in business.
I am rather curious about the ringing on the square wave, seems like an awful lot for a frequency standard. If it is, perhaps this is why it’s retired?
Variations in the speed of light in the atmosphere, due mainly to variations in moisture content.
That thing looks like part of a Proton Pack.
If you go back and check every post on hackaday by Mike Szczys then you can see they are all just lifted from Reddit. Whats the point???
psssst. people send us their projects. They also post them on reddit. sometimes they send them to other websites too. Shhhhh don’t tell anyone.
Come on Caleb, I can understand if it happened once in a while. But it is EVERY SINGLE post Mike makes. Not just one or two. Are you still sticking by that story?
that is so laughably untrue I’m not even sure how to respond. I won’t be egging this argument on any further since anyone can scroll through the pages and see how many stories Mike writes that aren’t on reddit.
This may have been a post from Reddit on some point, but Mike didn’t get it from there. He got it from me. I sent it to him on Sunday after my friend Kerry sent it to me. You can see he even thanks me in this article for it. I don’t know where Kerry got it from, but I don’t think he reads Reddit.
How about instead of critiquing Mike, thank the lucky stars for a cool sites like this, or better yet go and make some material of your own! :)
some of us dont read reddit so this is ideal.
+1
Nice STALO, but I bet as others have said, its probably on ebay for cheap for a reason… I would just hope that it’s for another component failure and not the Rb source itself.
Oh, and the ringing may be due to his hand held scope and probe, while being a nice fluke, is still not a $50k LeCroy or anything. And looking up that NSN brings it back to being part of a “Nimrod MR2 Aircraft XV236” of the RAF. Nimrod, really? Anyway, that is one ugly airplane!
in general being a DC square wave and his use of what looks like cheap BNC cable you will get some ringing … some LC or RC filtering at the end will help
I Googled images of “Nimrod MR2 Aircraft XV236” Wow! What an aircraft! It looks like something from another planet.
If you liked that, you’ll love the Nimrod AEW3!
And this one then, project lun
http://forums.finalgear.com/off-topic/project-903-lun-possibly-the-coolest-thing-youll-see-today-no-56k-42980/
http://en.wikipedia.org/wiki/Nimrod “Nimrod”, via Elgar’s _Enigma Variations_, which is exactly the sort of classical music that 50s/60s chief RAF staff would know.
http://en.wikipedia.org/wiki/BAE_Systems_Nimrod_MRA4 is of more interest, as it’s several billion pounds of “hacking”; trying to use antique airframes from the dawn of the jet age with modern radar. This didn’t go well and was eventually cancelled with extreme prejudice.
eatith,
I think the ringing is just because of the probe! I love my Fluke 123 – it’s by far my most reguarly used piece of test equipment since I bought it a few months ago. It came with a shielded probe but I couldn’t find it at the time I was doing this, so i just used a standard multimeter probe.
I think i found it on ebay… http://www.ebay.com/itm/GEC-Marconi-Stable-Oscillator-Aircraft-Part-612-1-52363-R8D-/130832014630
If you click at “7 sold” you can see he first bought one and then six more. :P
Thanks, Sherlock.
Quote from the source:
“After I found one of these inside the Mysterious Aircraft Part, i decided to buy the seller’s remaining stock (another 6 of them)”
bleh, (£60-£20) * 6 = £240 to pay college bills hahaha.
Who are you kidding… You just prevented 6 persons from getting a rubidium clock.
Everyone had their opportunity, its an open marketplace, anyone could have got there before him. He achieved a little something here; not big business, just a chap with skills and who got lucky. You’re just making yourself look like a right jealous so and so and frankly quite stupid.
Get over it Lorquet