Hi. This is a follow-up video from my previous one uh, having to play around with this Rubidium frequency standard I got from the Csoro it was their uh looks like their backup uh time measurement reference uh, Rubidium standard uh GPS Discipline: We've got ourselves a GPS uh reference oscillator here. We got ourselves a Rubidium frequency standard which I think might be a Stanford Research Systems one. we'll find out and we've got um four, um IR distribution uh amplifiers in here as well as a dual AC main source and I've had it powered up for a few, uh, tens of minutes and it took maybe 5 minutes for the rubidium to lock in.

The one pulse per second is pulsing. but I haven't got a GPS Uh antenna attached to it so I'm not sure whether or not that indicates that it hasn't I presume it hasn't locked I mean it is pulsing at once per second. but I don't know I haven't uh looked at the details of that one yet. So let's presume it's not um GPS locked at this stage it's just a ridum standard which is of course more than good enough for the Eev blog lab here and I've got it hooked up.

Well, I will in a second have it hooked up to the Uh Agilant frequency counter I also got here it is here we go and look at that. it is uh, this is the 10 MHz um out from that Rubidium oscillator and it is uh, significantly out. it's 71 Hertz out Now of course this one um doesn't have any um high order Um option on the time base. so it's only got the stock time base in it which is only uh rated to about 5 PPM or thereabouts, not taking into account um, their drift and stuff like that.

So 5 PPM on 10 MHz is actually going to be 50 hertz here. So I you know, so sort of. You know, as a rough ballpark, you sort of would have expected it to be under uh 50 there for this stock time base. but it's not 71.

So um, yeah, I You know I'm assuming that this Rubidium is, uh, you know, bang on because these things you know do not. um, they. they. basically they're they're you know, once they lock, they're they're pretty, uh, pretty reliable.

You can pretty much guarantee that you're getting bang on 10 MHz out I haven't checked the specs CU we don't know what unit, uh What uh, brand Rubidium is in there yet. but um, so that's significantly out. So um, assuming that Rubidium is spot on. um, this thing is, uh, probably needs a, uh, a tweak.

but let me hook it up here to my uh old. Phillips Here we go Old Phillips Pm 6672 and look at that. there we go. This one actually has an ovenized oscillator in there.

It's pretty good I forget the exact spec off the top my head, but it is, uh, fully optioned up with the highest um, ovenized oscillator in there. and it's basically bang on so that, um, pretty much confirmed terms that the Rubidium is locked and working and then if we take that out and we hook it up to which is kind of not really a proper frequency counter. but it's the uh ryol, uh DG 4000 uh series uh function generator and it's got a counter option here you can enable. It's got a counter on the Um input I Don't really like it.

it jumps around a fair bit. see, you can't really. You know there's no low order digits. sort of updating there, so you can't sort of.

you know, see where it's at? but pretty much you know it is. Um, the figures it's giving are well within that. um, well, you know, well within, say the 5. PPM We'll get in.

Um, you know that's in the order of, you know, a couple of PPM there. So um, it's You know it's pretty good. It looks like this Rubidium works fine. so I'm pretty darn happy with this thing.

So what we'll probably do now is just, uh, unscrew these and uh, take a look at what's inside because there should be a customized back plane in there and these uh, rack modules. these Euro card um style, uh option cars just slide into the, uh, customized back plane and um, we can have a look at that as well. but I'm really curious to know what Rubidium is in there. My guess is a Stamford research one which I've uh used before.

Have a bit of experience with those. They're very nice and uh, they're worth quite a bit. So let's crack it open and here we go. We're going to looks like there's a power box.

uh, power supply in there. it's going to it's got it. Looks like custom board built in. This would have been custom design by somebody at the CSI row.

or maybe they farmed it out. I I Don't know, but uh, we have custom board in there. There's our connector on the back and Tada yes Prs1 I was bang on There we go. It is a Stanford Research Systems uh model PRS 10 Rubidium Frequency Standard you know, industry standard Uh module probably every man made in the United States of America USA USA USA um serial number 25,000 These things are this rubidium oscillated I think it retails for about 1300 bucks or something like that.

These are, um, very good. uh units. very low, uh phase noise I've used them in very uh, critical systems and stuff like that. very low Phe phase noise.

So a nominal um Rubidium standard here for the lab I you know I probably never get another one of these things. So I think uh, this one's definitely a keeper. And all the distribution amplifiers? Wow. Um, awesome stuff.

So yeah, that's worth a lot. It's got like a 20year art lamp Li so there's no date on that one. but uh, yeah, and they get quite warm. That one's been going for, you know, 15 minutes or something.

It's heated up to at least 45 or something like that. So uh, let's have a look, see if we can, uh, get this board out and uh, have a look at the main board, but of course it's all in here. This is just going to be a power supply here and just a little uh uh, you know it's just some some connections and uh, stuff like that. Really, there's not going to be much at all.

Well actually there is a fair bit inside this thing because I forgot. um they do have on the back uh panel over here. From the outputs here they have direct uh Bnc's from this module which have uh 10 MHz in the 10 MHz reference output, the 5 MHz reference output and one pulse per second and a couple of each. Um, so they've got to have uh, some dividers on here and um, uh, stuff like that.

So we got an LT 1259 current uh feedback amp there and then just some Uh 74 HC series logic and two big uh Power bricks and some filter caps and some Bridge rectifiers. That's the AC input. It looks like it can select um AC or DC input. It's got the lead on the front panel over here to say which uh, power source it's actually coming from, so they they're really, uh Beast those Hercules 6 power modules Very nice.

Um, you know, 25 W modules. Brilliant and uh, there it is. Um National Measurements Lab SRS Rubidium Version 1 2001 So this would have been uh designed and laid out I guess by um, someone at the Uh C Iro National Measurements Lab and uh, this would have been designed as their um custom you know, their primary Uh custom standard and I've done uh, very similar things for uh Labs at companies I've worked out where designed I've designed and built uh custom, uh test instruments and uh, reference calibration instruments and uh, stuff like that in almost identical uh racks to these ones. so all very very familiar.

Couple of bodges, little bodge. there. there's a bodge resistor in there. there.

It looks like we got a bodge resistor across there. looks like they put a 75 ohm Terminator on the back of that. um oh wa, here we go. Whoa.

look out our rubidium. don't want to drop our rubidium um couple of bodge wies on the back. there few little shorts but uh, there you go. Um I mean you know it all.

The magic of course happens in the Stanford research module. They've got a nice uh heat sink here. It lookss like they've put some uh, thermal grease behind there to uh uh, spread the heat onto the uh shazzy. Of course this thing's going to get quite warm during operation, but uh, that's that's all there is to it.

You know there's nothing fancy on here, just some dividers and stuff like that cuz they do build this into Stanford research I can't remember the model number but they do. um I used to have one um from my old company. they um, build this same rubidium uh standard and they sell a product that has all of you know, a similar board to this building. It's got like you know, 20 Bnc's on the back which has all the 10 MHz 5 MHz 1 PSE per second output.

all that sort of stuff sort of uh, built into s of you know a usable U an actual usable product because if you just buy this Stanford research rubidium module you'd need to add the other uh stuff around it. You know you got to add the power supply and stuff like that. In fact, there it it. uh has the pinouts on there.

There it is. 10 MHz reference output plus 7 dbm. It's got the lock and the one pulse per per second output. so I can now look up the manual for that and go aha what happens if that one's actually um, you know, flashing.

So and then there's a analog frequency adjust and I'm probably not doing anything with that um Txd monitor. One pulse perant in or photo out plus 24 volt Supply blah blah blah. There you go. So beautiful little Stanford Research module There I Love it! Huge score! And now for the GPS card.

Tada That's a great thing about these racks. You can just slide them in and out. Oh look at that. They've actually, uh, put, look at that.

They got the coax going. They designed that so that sits right out the back of the case like that. so you know that's what you do when all these things are custom designed. but oh, look at that isn't that fancy.

I like it. very nice. We take a good look at that. and if you've never seen inside one of these uh Euro card rack and you know it's it's not much.

I mean there's a uh oh no, that's an IRT Okay, so what they've done. They haven't custom designed the uh back plane that's an IR brand. same as the uh, same as the distribution amps here. So they've just bought an off the-shelf IR uh rack, you know, rack unit and the back plane's been designed by them and it's got holes up in the back of the board that can just poke out the back there.

and uh, that's it. So they've just, uh, you know, designed. They're standardized around that so they've just gone right. We'll use one of these IR We need the IRT amplifiers anyway.

They come with a nice dual AC power supply and all that sort of stuff. So we need the distribution amps so we'll just buy those off the shelf by the whole rack and then we'll design our uh Rubidium uh standard and our GPS standard to go inside that. So let's see if the Uh I don't Yeah, the Nmi looks like they've done this one too. There you go.

It's the Javid B031 Nmi National measurements Institute 2004 and it is a uh Topcon they call it Euro Half Well, half Euro uh GPS receiver and it's a Uh Javid Navigation Systems of course. Uh, you know Nmi wouldn't have designed the Uh GPS receiver in this. They're just designing the backboard here. the Euro card backboard to, uh, sit here.

They've got a riser board going up here to mate into this off the shelf. uh one from Javid Navigation Systems I will, uh, look at that package, look at that. don't know what's going on there, but uh, got a big metal can down the side. not sure what that chip is.

we have to get the right angle on that and the macro lens. but uh yeah, just an off-the-shelf Uh GPS receiver. No surprises at all, but they have to be specifically designed. I Mean, you know, not all GPS Re receivers are suitable for this.

They have to have not not only the one pulse per second um, output, but you know it really has to be like a you know, low phase noise and blah blah blah. everything else it's got to be. You know it's got to be properly designed. If you're you know this is obviously the primary reference uh standard for the uh National um Institute here.

and really, you know they, you know they're not just going to whack some eBay uh, cheapy in here so might made in USA There we go. So I might actually have a look at that one and uh, see if I can get any data on it. No, as it turns out, I couldn't really find any info on that I think it's a really old model. They do make uh, the same ones.

these Euro card um connector interface modules. they still do, uh, make them but I think it's a slightly older one that metal C by the way is a battery under there and the board's actually uh, conformally coated. If you can see the uh see the coding on that perhaps so you can tell it's conformally coded. You can see the gloss on so you know the side of the chip down there, you can see see that glossy coating.

They put a clear conformal codeing on this board. Maybe it comes standard with that because the uh, uh, The Other Board of course doesn't have uh, any conformal coding on the custom board from the Nmi. and by the way, um, no surprises. It's uh, hand solded.

Um, you know they would have made uh, probably two of these. um, one is the primary one, one is the backup one which I've got here so you know. um yeah, someone's are crusty hand solder in there. They've had a hack job at that which is a little uh, little regulator there.

Nothing special. it's just a power supply and a 74 uh 244 basically hooked onto the commercial. uh GPS receiver. They've got some uh Dallas semiconductor stuff down in there, probably little um ID stuff and brick power supply.

Of course, when you're designing a custom uh bit of test gear like this, you don't bother around doing the power supplies you're only going to make. As I said, like a couple of these, I've made precisely one of something before you know or I've made 10. You're not going to dick around, You're just going to use an off-the-shelf power module. Yeah, they might cost 50 bucks from Digi key.

but whoop-de-doo Who cares? You know? I mean gez, you know your your time's easily, you know half an hour of your time's easily worth that. So you just buy off the shelf shelf ones and they work. and uh, so there you go. Just an off the-shelf uh GPS receiver.

We've got some uh, stuff on the back here in terms of uh, what is it just a power supply stuff? Really? nothing. uh, particularly special. So there you go. Um, I'm going to have to, uh, actually try this and get uh GPS coverage on the thing.

I don't actually have a connector for that so it looks like it's yeah, there it is. right right angle over there I don't have a uh GPS connector to uh, fit that at the moment. but I will endeavor to, uh, possibly get some GPS reception for this thing see if it still uh, locks in but ah, you know I'm not that, uh, fussy here in the EV blog lab. I've now got a Stanford Research Rubidium Beauty and here's one of these IR video Distribution amplifiers cuz that's essentially what they are.

It's A called a Vda. it's the VA uh, VA 761 model. They're just video distribution. uh, amplifies quite good ones of course and you can adjust uh, the equal gain and Equalization of these things because these, uh, cuz the 10 MHz reference outputs of these uh, Rubidium.

they're just um, side waves so effectively, you know a video distribution amp is what you want. So yeah, there's not much on there at all, just some uh Atlantic there you go. they went. uh, they went bus didn't they or they were, uh, bought out by someone Atlante, uh 212s and 2054 204 for 20 45s I think can't really read that but uh, there you go.

It's got a hum adjustment as well. Look at that. um yeah, just at Lantch Video Distribution amplifiers Atlantech were uh, very big in the Um video opamp and uh, that sort of video driver Market You know, big, uh, cable drivers and things like that I've used those before so nothing fancy there at all. shielding plate on the back nice touch.

I like it. so I've got three of those plus a V700. It looks like it's got an output Monitor and a selection switch. Not exactly sure what they're using that for and it's another video distribution amplifier.

Bit more complicated than the other one. got lots of uh, looks like we got some discreet on here. look at this front end W adjustment pots been to somebody's with a gray beard and right T Anglers tweak those and sealed the Uh pots off there and we have some Bur Brown Op amps. Nothing really special.

eh, it's a Euro video distribution amplifier. Woohoo! And on the back here they've gone to the trouble to uh, of course designer custom uh back plate as well. nmi there it is. this is for the Uh GPS receiver.

couple of buttons on there push, what does that do? FN no here, there's another one power button down here and uh, there is our reference. Well, that's our Um antenna input here I'm not sure where these cables are going to then. not sure what's going on there. Ah, I see what they've done? It's just a patch cable.

It's basically uh, just uh, converting here. This plugs into there like that and it just converts it to a more standardized connector. and I showed these in the previous video there the custom Nmi: um SRS Rubidium back plane one pulse per second output Fact: They got two of those, They got two 5 MHz outputs and they got two 2 MHz outputs as well And they've got it. Looks like a power supply connector output isn't populated and a comms Port as well just for uh, getting the data out of that uh, Rubidium? uh, oscillator if they want.

So the whole idea of course, is that you just take your 105 or 1 pulse per second output. you just, uh, put them into the inputs here and you got a whole bunch of outputs to power all of your lab gear. and uh, all of well in this case from the national measurements. uh Institute, all of their um uh standards and test gear and frequency counters, and Scopes and Spectrum analyzers and everything else all uh GPS uh, Disciplined Rubidium and I thought I'd take a quick peek inside this Agilant frequency counter here.

Haven't taken one of these parts before. Look at this. It's a bit how you doing. I mean you know, look at the Just The Bear power supply.

Sure, it's got the nice, um, you know, insulated flap over the top, but like it just what it's just sitting there. I I don't know I didn't expect that. I was sort of, you know, being mooned again like you open it up and bl there's this ugly, you know, third party? um, you know. I'm sure it's a reasonably, uh, good quality, uh power supply, but I don't know, it's just anyway.

look at the ton of room in this thing. they've um, got a zyink uh fpga down there or P Here's the bottom of it. quite a bit on the bottom actually. um, obviously this, uh, these options.

The this space in here is for, you know, various uh options. probably for the uh, you know, the high performance oven oscillator and uh, stuff like that. but yeah, a nice little touch of put a plastic foot on there just to support the board on the back case when it slides on. This isn't going to be a full tear down I Won't even bother with the uh, close-ups.

but yeah, oh, that's a bit disappointed with that. I was hoping to, uh, um, open it up and see if there was a tweaking uh cap for just the uh, you know, the 5 PPM Crystal oscillator. but I think it's going to be under there somewhere Bugger? No idea what that board from ERG is doing there. Off the off hand, it's got a, uh, little isolation Transformer on it.

Not sure what the other Chip's doing and uh, don't know. they've gone to a bit of trouble to uh, mount a third party board off. there. there you go.

I just flipped out the power supply. yeah, manufactured by uh Delta 4 HP it's got a HP part number as you'd expect. um, dodgy little uh fan on the thing. Bloody hell.

it's loud and it goes when you actually, um, don't even have it powered on because it's a soft power switch on the front and you might have heard it in the background. uh, going before in some of the uh at the start of the video and yeah, hopeless. Unbelievable. Anyway, there we are down in there.

looks like we have a motor roller processor. We got some ROMs there and uh, where's our oscillator? That metal can down the bottom? Oh I think there's an adjustment pot on the back Do? didn't even see it. see the thing's turned off and you can can probably hear the fan noise. Listen, there you go pain in the ass.

The fan, just you know, stays on and it's just a soft power button. Crazy. Anyway, it's powered it up. it's doing it self test pass Gpib? yeah, blah blah blah.

Now we can plug it in. we can calibrate it all right. We'll give it a go. Now, the most important thing with calibration adjustment is the tongue angle.

It's got to be correct, and if you're a stute, you notice the one eye Popeye technique as well. Very important. one eye tongue at the right angle like that and a uh, nonmagnetic, uh, non-metallic screwdriver as well. For these, uh, I'm assuming it's a cap on the back there, so one of these, we should be able to tweak it.

Ah, half a be dick I don't know. it's a bit dodgy. It's hard to do it, but jeez, I'm running down to 30. That's Ah 30.

PPM That's hopeless. Let me try and do it off camera. Tell you what this ain't This ain't easy. ah can't talk and have the correct tongue angle at the same time.

But gee, there's ah, this part. these stock standard oscillators are crap. That's like as good as I can get it There we go. Four Four lousy.

PPM in that that's oh sorry. 04 uh PPM So yeah, cuz it's 10 MHz So that you know that's okay. but yeah, these stock oscillators are awful I mean you know I was, um, putting. you know that like it's sort of got some springiness to the adjustment in there and then it just there's no sweet spot.

I mean it's just. ah, it's just awful. But hey, that's all right. 6 PPM Good enough for Australia Catch you next time.