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- เผยแพร่เมื่อ 31 ก.ค. 2014
- Dave upgrades his HP/Agilent 53131A frequency counter with an ovenised oscillator module from ebay.
www.ebay.com.au/itm/121330209846
www.thinksrs.com/downloads/PDF...
www.2917.com/EBAY-images/NOX01...
cp.literature.agilent.com/litw...
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Actually, there's a huge amount of satisfaction seeing all those zeros!
Simon Crabb Agreed!
It would be interesting to blast that little trim pot with some heat and watch the drift. Then maybe putting a small Styrofoam cup around the pot and adding some lead length to the pot legs with some fine curled wire to further isolate the temp changes through mechanical coupling to the board. Would be a neat project to see how stable you could make that 10MHz block. I imagine the oven circuit is one designed to search for equilibrium???
I'm disappointed Dave didn't remark that you can fly to the moon on 17 Watts.
I was expecting that too! :O
googled "you can fly to the moon on 17 Watts" and this was the first result, www.eevblog.com/2011/04/19/eevblog-164-agilent-fly-to-the-moon/
You give new meaning to the term splitting an RCH.....well done
Nice work Dave, thanks.
I have no idea what any of this stuff is used for but recently I've found myself watching your videos from start to finish. Really impressed by how well you know your field. I'd be interested in a teardown of that ps3 you got in a mailbag.
I do really like the ending of this one!
The frequency counter in the Rigol is crap - it uses a binary count period so gives silly results and meaningless lower digits. Try plugging its own 10M ref out into the input & see what happens
Yep, I know, it's awful (thought I put a text overlay saying that? maybe I forgot?), but at least let me show the drift up and back down again. I was going to use it to show the offset differences in the frequencies, bu it couldn't even do that right.
EEVblog
about to watch the video, but if you didn't, that's what youtube video annotations are for!
Except annotations aren't displayed on mobile devices or tablets.
***** Yep, often I add annotations and people never see them.
*****
Most people turn off annotations because a lot of channels spam the videos with links.
Those are some crazy accuracies!
Thanks Dave. Although I'm just a hobbyist and don't need that kind of accuracy, I still enjoy the videos.
What about the effect of the temco of the trim-pot?
Another great video Dave !
I just ordered one.
73 N8AUM
I was going to tell you to check out the freq upgrade module on TheSignalPathBlog that i saw a little while back, but when i checked it out to get the link i noticed you had commented on the video too !
Dave,i love what you do :) You should be a tetcher, or just keep doing what you do!
I'm quite happy to buy a used Xtal oven ref. Used Xtal ovens drift less than new ones. The older the better.
Good video.
Here's a technique which might work for you with that counter, but certainly works for microwave counters which only have a resolution of 1 Hz.
Instead of feeding 10 MHz in to the counter and adjusting the timebase to read 10 MHz, feed in a higher frequency. In the case of my 40 GHz microwave frequency counter, I fed in 20 GHz from a signal generator that used a GPS locked frequency standard. Hence the 20 GHz would be very accurate. That makes adjustment much better, as all 11 digits are used, not just 8 that would be used if measuring 10 MHz. However, I found it a bit pointless worrying about the last couple of digits much, as they drift after a couple of days.
Using a higher frequency on the input might not help on your counter, as I assume that's a reciprocal counter. But it works on direct counting counters.
I would think the internal temperature of the counter would affect the frequency of the crystal, despite the oven.
I think the higher stability ovens are just selected versions. When they are old, there's probably no advantage in the ultra high stability version. It's probably just luck at that point.
Not related to this episode, but could you do a video on how induction motors work, and repulsion motors work? I am working on a repulsion-start induction-run motor for a metal lathe and I cant find educational videos on this specific type.
This thing looks nifty, and clearly the upgrade was a good idea... Not sure what I'd use one for, myself... the fastest electronic thing that I mess with is the 16 MHz ATmega processor in my Arduino-based handheld console.
What's the temperature stability of that trim pot? I noticed the frequency drift was still climbing up throughout the video. Hit that trim pot with freeze spray just a quick shot I bet it will drift a lot.
I'm not sure if it was covered, but changing the XO require a calibration and adjustment
The Rigol DG4162 does have software logging but in the form of LXI, a web interface. So you can read out values on a pc, accessing it's IP address directly in your browser.
Pepijn de Witte Yes, but it doesn't come with any software to just capture and log data, you have to right your own.
when I sawthis video first time I got sad I couldnt afford this counter. and now I have one :)
Dave,
The MV89 is a Russian (Morion) osc. It's pretty good but I like the Milliren 260, it runs at lower current but hard to find in 10 meg on ebay. Milliren sells it for about $1k so you don't want to buy it new.
Rob
Awesome.
No XY plot?
Also this counter goes to 15 digits interrnaly. Worth checking with some softwarere for drift rate testing
Hey. I was wonder if you could show me how to using Frequency Counter? I have old HP frequency counter nixie.
hello, i have similar counter, why in the cal menu is not displayed Timebas? is automatic decoded the oven reference?thanks
I have in my collection Nordmende 20MHz counter with nixie tubes!
+Hrvoje P. jOvHs7D8oHI
Hi from Perth Dave. I notice that the underside of the board (seen at 4:45) has what appear to be hundreds of tiny holes in the PCB trace. Any idea why?
JeremyJ That's caleld via stitching. It is used to lower the impedance and inductance of the ground plane.
Thanks! Makes sense now.
How do you trim an ovenised oscillator if you aren't lucky enough to own your own rubidium source?
Drift per year is that permanent?
I mean does it just count 1hz over a whole year or does accumulate so that it counts 10hz wrong per year after 10hz years?
That OCXO was made in Korea...
MOAR OVENIZATION!
Any chance of getting a GPS antenna on the roof of your building? That would be a nice additional upgrade to your rubidium standard. I assume you use it free running right now.
sapperlott Probably zero chance unless I wanted to foot a huge bill.
How can the frequency counter be so accurate without its own oven oscillator?
Eehm, Dave, no "Hi, Welcome to the EEVBlog" intro? i personaly dont mind it, but, hmm, weird... :D
The oven controlled oscillator is calibrated compared to the rubidium standard. So, what's the next level - what are the rubidium standards calibrated against?
A cesium standard or a hydrogen maser.
tilt that one over and see how much gravity effects that oscillator..
Had the same idea. Tilt it Dave!
Signalpath blog did a review of a knock-off 3GHz option board he found on ebay for $100. Is was interesting to see BG7TBL on the board, I have a DDS board designed by him
Have you seen Gerry Sweeney's (th-cam.com/users/gezzasw) video on this and the adapter boards he got made up?
Do math functions on scope, the drift would be easier to see. Or use x-y mode.
Good drinking game, every time Dave says rubidium or ovenized take a drink :P
XD the frequency of this oven oscillator over-time is going to rely on that crappy 1 cent trimpot, which will have a shockingly bad temperature coefficient and horrible stability with the slightest vibration. Definitely the weakest link in this setup is that 10-turn pot.
Can you tune my guitar when its done?
7:22 No scepticism at all with this Chinese datasheet...?
Has anyone else ordered one of these? Mine came in after a long delay because they “forgot” to mail it lol. Although it looks the same mine is missing the oven ready LED and couple filter caps topside and the output of the xo is going into a 7404 (U2) and only 1 single output is going into the main board rather than a differential output. Counter seems to work but I have no way of checking accuracy or drift since I have no standard to compare it with. If anyone has a working one I would appreciate if they could tell me what U2 is.
73 Vidas N8AUM
NEWBIE QUESTION: Can anybody tell me why a frequency counter would be useful over having an oscilliscope which could tell you the frequency of a signal?
oscilloscope isn't quantitative, freq counter is
For the layperson, what is this machine for?
With that gear you can measure frequencies of periodic signals
The trimpot stability is probably much worse than the rest of the oscillator.
Gerry Sweeney has some nice boards available. As well as a series of videos on the design and operation of his board.
gerrysweeney.com/update-diy-hpagilent-53131a-010-high-stability-timebase-option-pcbs-available/
I'm just gonna stick my frequency counter in the oven at gas mark 10 for an hour.
Oy; thought you were going to bodge in an oscillator of your own design?
Didn't think you would use a plug and play unit. Guess that populating the missing DAC was too much to bother with; can understand that..
If you really wanted to do a useful bodge, add a 9-turn pot in series with the 9-turn pot on the osc board that is ~1/100th the resistance of that pot. Seems too simple to consider; but that should give you that extra fine adjustment capacity. One will be a coarse adjust and the bodge is now the fin e adjust. After all, if you count on your counter like I do, you can appreciate the accuracy. Bah; who needs a counter that can be accurate up to /10 of a Hz - anyway?
(Robby - from the eevblog)
BTW - you did mention that one can align a freq counter using GPS/Rubidium standard. Perhaps another viddy could be done? Not everyone needs or want to get a Rubidium of their own just to align their counter every blue moon - so to speak. Could prove to be useful
What, no tear down ? what happened to don`t turn it on take it apart
Just kidding great video
I can't see how this is going to be all that accurate with that ribbon cable, and its transmission-line parasitic capacitance(s) and inductance(s). Ewww... Plus, it's probably going to pick up noise as well. I would have expected a daughterboard that plugs in to keep lead-length to a minimum, plus a support bracket to keep it from flopping around if you move the counter, due to the mass of the brick-like oven assy.
William Squires Obviously good enough for the official Agilent mod which fits exactly the same way.
You remind me of my girlfriend; she's always commenting on tongue angle too.
Use gravity to adjust to zero...stick a book under the front.
Those multiturn trim-pots are garbage.
Pretty much. Even the expensive ones have horrible drift and ageing specs. It would be interesting to see how much the indicated frequency changes when he put the cover back on and let all the components come up to temperature.
Libre LXI tools for everyone that is interested
github.com/lxi-tools/lxi-tools