nanoVNA - Determining the Resonant Frequency of Crystals - VE6WGM

[@seanstraw8688]

tip: set your SPAN to say 5MHz, then you need only set the CENTER when you're moving up in your initial search, then when you get something close, you can shrink the SPAN.

[@dennyoconnor8680]

Us crusty old hams don't need fancy electronics. We know that all you have to do is jumper the crystal in series with the antenna to the receiver. As you tune across the 'supposed/suspected/marked' resonant frequency the incoming noise/signals will jump in amplitude quite dramatically - usually blowing your headset off. All done in moments and it's Miller time.

[@KenWiggerAnotherAncientGamer]

I am a crusty old ham WD9GNG after 40 plus years. I never tried that and I even like Miller beer. I will dig some crystals out and try that. It seems like fun. I also have a nanoVNA but I like your way the best! :-)

[@ve6wo]

That’s pretty slick! Thanks for sharing :-)

[@alklapaxida850]

the great, regards from VK3

[@matthewkleinmann]

I think he was referring to Glenn Miller...

[@tomchristian2400]

I like the fancy electronics. They seem more straightforward. And besides, if you don't know the frequency of the crystal you might be doing a lot of tuning to find that resonant frequency.

[@randyterrell2261]

Greg, very well done and presented. As Nelville points out, crystals are sometimes optimized to operate on fundamental OR if higher frequency needed, their 3rd and sometimes 5th harmonic; i.e.: 3rd and 5th “overtone”. It’s difficult to process a crystal with a fundamental frequency in the 10’s or 100’s of MHz as they get very thin and thus fragile so overtone crystals are very common above about 20mhz.

[@ve6wo]

Thank you for your comments :-)

[@steveseabrook7659]

Excellent video, unhurried and comprehensive explanation, thanks Gregg. I really enjoyed it!

[@ve6wo]

Thank you. I like to try to keep things simple and relaxed :-)

[@nevmarr]

well done Gregg, great video. Your conclusions are spot on. Some crystals are manufactured to operate on their fundamental frequency, some others are manufactured to work at their third overtone.

[@intotheblue50]

Your testing here is fascinating, really useful and enjoyable, thank you for sharing.

[@lorjo_lovetopaint]

You should be a professor in this field of science! Excellent teaching ability!!

[@craxd1]

What I think you're seeing: "Every quartz blank has its basic frequency. Besides this “fundamental tone”, each quartz disc has several overtones. When electric voltage is applied to the quartz, it oscillates on its fundamental tone. Its overtones are also triggered in this process, but their signal is significantly weaker than that of the fundamental tone. In fact, most of the time the overtone signal results in nothing more than normal phase noise. "By clever construction of the oscillator circuit, it is possible to actuate the overtone of the quartz instead of the fundamental tone. Therefore, an additional resonant circuit is added to the oscillator circuit in order to amplify the overtone signal of the quartz. "This technique allows engineers to “squeeze” frequencies far above its fundamental tone out of a quartz crystal. For example, if a quartz oscillates in the fundamental tone at 20MHz, the third overtone oscillates at 60MHz and the fifth overtone oscillates at 100MHz. Due to the electronic properties of the oscillator circuit, the overtones can only be stimulated in the odd integer range" .

[@user-su5sq5ib3i]

Makes sense, that a 6.8M crystal third order is 20.45M. That is usually its strongest harmonic I believe. These are great videos. I just recieved my vnaF and learning alot here.

[@W1RMD]

Broken crystals can do weird things. Great video and excellent description of crystals! Thanks!

[@williamsanchez34]

Muchas gracias muy util tu video y la explicacion que das alli , tenia que medir unos cristales de un generador de carrier de un radio hf y no sabia como hacerlo gracias a tu video pude medir los cristales y verificar que estaban resonando a la frecuencia adecuada gracias de YV5JAU

[@ve6wo]

I’m glad you were able to make use of the information I presented in this video!

[@on2wi]

Very interesting Gregg, we used to use this harmonics effect a lot back in the 70's - 80's as a cheap replacement for our 2Mtr xtal rigs ( 145.500 -10.7 ) / 5 = 26,96

[@petrok1rp254]

Just hint ...18:50 use search for minimum and maximum marker function to find peak and dip instead of manual tune. Anyway great vid!

[@ve6wo]

I’m going to have to practice using that feature so that it becomes habit. It is a very useful feature for sure, but I keep forgetting to use it! I’m used to manual controls for instruments (I guess I’m getting old, haha!)

[@Peter-ps3lu]

Hi,thanks a lot for your video about nanovna Greetings from Buenos Aires,Argentina

[@ve6wo]

Greeting from Canada, eh! Hahaha! Glad the video was helpful :-)

[@Bazzawombat]

In the 70's and 80's, I ordered many xtals from Jan Crystals. They asked for fundamental frequency, series or parallel resonance, 3rd or 5th overtone, series or parallel capacitance. A lot depended on the actual crystal oscillator. Shame I didn't keep old jan crystals catalogues, thanks for posting. VK2FP/AG7VC.

[@ve6wo]

Thanks for sharing :-)

[@nobodyspecial8102]

Thanks for a great lesson on resonance circuits , I received my nanovna saa a couple of days ago primarily to tune air core coils and the cells in an hho generator. Your description is the best I've seen and as someone commented the vna been used as a spectrum analyzer tends to divide peaks from a quality signel generator into 2 maybe because it relies on harmonics to cover it's sweep frequency range. I belive the V2 plus 4 does not use harmonics to sweep the declared range but is twice the price.. Looking forward to your next lesson 😀

[@OC35]

Sometimes the marked frequency is the receive frequency of a receiver. The actual crystal frequency is the local oscillator frequency of that receiver.

[@hebrewhammer1000]

Great video! Thank you for sharing.

[@W4BIN]

I noticed that he is controlling his VNA with a pencil eraser, better he should use the *soft* graphite end, the eraser is rubber compounded with pumice an abrasive powder, so he is gently damaging the surface of his glass of plastic screen protector minutely with every stroke. That damage is cumulative. Otherwise a nice presentation. Ron W4BIN

[@ve6wo]

I had no idea. Thanks for bringing this up Ron :-)

[@bachkhoa1975]

Here are my suggestions: 1. Instead of using alligator clips and cables, use a solderless breadboard (with .1” spaced rows) and appropriate SMA connectors (and the SMA cables that came with the NanoVNA0.) The setup is much more solid and results are more repeatable. 2. Use the nanoVNA-saver SW. Manipulating the scan parameters, the markers etc. is a lot easier. It also has a function called “Analysis” that identify the peak resonance frequency (when already in range, of course). Great video nevertheless. You should show how to compute the parameters of crystals such as Lm, Cm, and ESR using the values acquired by the nanoVNA. Also, show how to measure the package capacitance Ck.

[@RomanKuechler]

Very interessting, thanks!

[@RajibKarmakar-m5j]

Thanks for sharing crystal oscillator.

[@josealbert4596]

By placing a piece of copper wire like a hairpin or some coils between the two ends, it acts as a griddip

[@Miller7747]

You can also use a spectrum analyzer and tracking generator

[@Pixelwaster]

"When measuring the series and parallel resonant frequencies, be sure you don’t inadvertently measure a spurious resonance, as most crystals exhibit several spurious resonance points above the true parallel resonance point." - From Crystal Motional Parameters A Comparison of Measurement Approaches by Jack R. Smith K8ZOA, 11 June 2006, Page 13. A copy can be found here -> www.mikrocontroller.net/attachment/473317/Crystal_Motional_Parameters.pdf

[@ve6wo]

Yes, good point. I noticed some of the crystals I looked at had resonances at various frequencies. Harmonics.

[@ve6wo]

Just read the article. I did have one crystal that had some spurious resonance points, and I think I mentioned this as a point of curiosity. Thank you, now I know what is going on :-)

[@clifffiftytwo]

Those "multiple resonance" frequencies are interesting. What would happen if you re-calibrated at the narrow sweep range you used after adjustment? I have no idea what's going on but I wonder if the extra resonances are an artifact of the measurement device? Or caused by the extra inductance / capacitance of the connecting cables? My nanoVNA is in the mail LOL. Another experiment - test a crystal connected at the end of a 100 ft long piece of coax!

[@ve6wo]

These are good thoughts. I hope you enjoy your nano VNA as much as I am mine. If you find interesting things in your experiments maybe make a video and post. Feel free to drop the link here :-)

[@vironpayne3405]

I think we can all agree that a nanovna is better than a set of Gensu knives as far as versatility and utility, and Greg's excellent video is more proof. I did watch a video on why a nanovna is not so great when used as spectrum analyzer due to internal filtering artifacts as someome else mentioned. That does cause me to wonder if a narrower calibration range might help cure "some" of the artifacts, if that is what is being observed. If I hadn't seen the video on using a nanovna as a spectrum analyzer, I would be thinking of other related weaker frequencies in the crystal that muscians would refer to as timber of an instrument. Crystals are natural resonant structures and I would expect some frequency impurities away from the fundamental designed frequency. Then the more engineer mind thinks, is there a reaction between the crystal and its housing? Lots of thoughts. Again, thanks for a great video.

[@ve6wo]

Valid thoughts.

[@johnwest7993]

I believe that's what most of the parallel capacitance consists of. That and whatever base is used to hold the crystal.

[@robolt]

This video may explain the spurious resonance you see a few kHZ above the resonant freq. of the crystal. It has to do with a secondary heterodyning oscillator within the VNA. The possible explanation is at 14:09 to 14:50 in the video. kzbin.info/www/bejne/invGmqKig5KDd7M

[@kd5ozy]

bravo!!!!

[@johnhess351]

Are my horde of 100s of 75 year old radio crystals still good if stored properly?

[@petrok1rp254]

25:45 it is so called “third overtone” crystal...

[@kv4atv]

Please post/show the hookup for the crystal to the NanoVNA to measure this and other things. This video didn't exactly explain or show it so I can pass it on to others that are asking. Could you also show how you calibrated this set of test leads to get the reference plane correct. KV4ATV Florida

[@ve6wo]

Hi, thanks for the comment and question. The Crystal is connected in series with port 1 and port 2 (red connector from each test cable). The two black connectors from each port are hooked together. Calibration is done as follows: leave the alligator clips on the test cable connected to port 1 disconnected, use that for OPEN. Clip them together for the SHORT calibration. Then connect two 100 ohm resistors with short leads (placed in parallel to make 50 ohms) for the LOAD calibration. For the ISOLATION cal, simply leave the 50 ohm load on the leads connected to port 1, and leave the leads connected to port 2 open. For the THRU calibration clip the two red leads together and the two black leads together. Hope this helps :-)

[@jeffreyrichard9675]

@@ve6wo I could have sworn I read for the ISOLATION cal the load should remain on port 2 and 1 is open. Can you please confirm? Thank you and 73!

[@ve6wo]

@@jeffreyrichard9675 Ideally, both should have a 50 ohm termination installed, however, it seems that my nanoVNA’s port 2 has 50 ohms internal impedance and leaving it open does not seem to effect the readings. If a person wants to be safe, simply use another pair of 100 ohm resistors in parallel and terminate both cables/alligator clip sets with 50 ohms. Try it both ways and see if there’s any difference. Feel free to come back and share results :-)

[@ramonbennett8416]

Nice demonstration, not to complicated to follow along with. Nice job 👍 KN6JHC

[@w5cdt]

Crystal appears to have a spurious response

[@kaisernisar3266]

Hi you made a very informative and interesting demo. can you please explain how you took account of or calibrated the SMA to crocodile clip cable impedance in the VNA setup Many thanks

[@ve6wo]

Please see this video at the 2 min 30 sec point. kzbin.info/www/bejne/n3uUon57arRjmLs

[@benoitraulin1264]

Super c'est mon cours de rf merci

[@macgyver5108]

I've been under lockdown too long... 17:16 "DR. WE HAVE A PULSE!"

[@ve6wo]

Haha! I know what you mean!

[@randytrue4019]

could you post what parameters in the menu you used. I see how the crystal was physically connected, but not which settings to use.

[@PaulaBean]

How exactly did you connect the crystal to the ports? And is it also possible to measure coils and capacitors this way?

[@ve6wo]

Please see reply to KV4ATV for calibration and connection of the DUT. Yes, you can measure inductors and capacitors using the nanoVNA. I am working on a video to describe how to do this :-)

[@ve6wo]

The center pin of port 1 is connected to one lead of the crystal. The center pin of port 2 is connected to the other lead of the crystal. The grounds for ports 1 and 2 are connected together.

[@mikem5043]

How did you do your calibration using the alligator clips? Especially the 50ohm cal

[@ve6wo]

I did an open-short-load calibration. Open - leave the alligator clips disconnected. Short - connect the alligator clips together. Load - connect the alligator clips across two 100 ohm resistors with short leads soldered together in parallel.

[@mikem5043]

@@ve6wo Roger that. Then I assume 'thru' was alligators clipped together between S11 & S21, and 'isolation' was done with the S11 and S21 each connected to a set of 100ohm resistors( in parallel) independently but at same time (???)

[@ve6wo]

Yes, except I did not terminate the lead used for S21 with 50 ohms for isolation. The nanoVNA doesn’t seem to care due to how it’s built. This might get a person in trouble though, if in an electrically noisy environment as there’s a chance the leads may act as little antennas.. probably a person should use a 50 ohm load to be safe.

[@mikem5043]

@@ve6wo Got it. Thanks for your time and all the good info!

[@EonTide1111]

Are you a electrical engineer? Or what is your title for your career ?

[@ve6wo]

I am an Electronics Engineering Technologist.

[@stevec5000]

If you connect the crystal only to port 1 the same as when checking coils and caps what do you get?

[@ve6wo]

Sorry, I’ve never tried that. If you’ve got a nanoVNA, go ahead and play with it. If you find some interesting things maybe make a video and post it :-)

[@h0ll0wm9n]

You didn't show the menu settings for the NanoVNA to get it into the right mode for measuring crystal freqs. E.g., Start and Stop freqs. Also, you did not show/describe the physical cable / alligator clip rig.

[@td_44]

большой кварц на третей гармонике работает, у меня такие встречались, непонятно каким образом , но они работали

[@CHUCK.H57]

My poor effort to translate TD44. Please forgive the faults of google translator... ND5CH/UT1ZT TD44. 1 week ago large quartz at the third harmonic works, I have met such, it is not clear how, but they worked

[@td_44]

@@CHUCK.H57 There is a resonance frequency with the best Q-factor, but for some reason quartz prefers to work at the third harmonic, at which the crystal resonance is very weak, it happened, why quartz did not start at the fundamental operating frequency, and this is not clear.

[@AB-yu2tj]

How about figuring out why resistors overheat in a circuit come on help me

[@ve6wo]

Well, this is not exactly relevant to the nanoVNA or crystals, but.. Resistors have only so much ability to dissipate heat. They are rated by their power handling ability, and a fairly simple calculation will tell you what power rating is needed. V^2 / R = P (watts)

[@JJ-vk2bg]

What's more important thing is how to connect wire to VNA and to the crystal! But you don't show me this. Would you?

[@ve6wo]

The red clip from port 1 connects to one leg of the crystal. The red clip from port 2 connects to the other leg of the crystal. The two black leads from ports 1 & 2 connect together.

[@johnkemas7344]

I like the video, but a more detailed shot of how the Nano was wired to the 2 ports and the crystal would have been helpful. the Nano is great but has a long learning curve!

[@ve6wo]

The center pin of port 1 is connected to one lead of the crystal. The center pin of port 2 is connected to the other lead of the crystal. The grounds for ports 1 and 2 are connected together.

[@johnkemas7344]

@@ve6wo thanks for the update!