Re: [time-nuts] Are there SC-crystals out there in the wild that are not Overtone?

Hi As long as we are beating up on the poor old SC for mode issues: We have an C mode ( = the one that normally gets used in a precision oscillator) We have a B mode ( = the “thermometer” mode that gets used in some MCXO’s) Hmmm …. why did they start with B … hmmm …. Well yes indeed there

Re: [time-nuts] Are there SC-crystals out there in the wild that are not Overtone?

You are right. As I am usually stating in my crystal seminars: "You are ordering a crystal with one particular frequency, but the manufacturer supplies with the crystals free of charge a bunch of additional frequencies, which are not mentioned on the marking." There is a multitude of spurious

Re: [time-nuts] Are there SC-crystals out there in the wild that are not Overtone?

I am glad you could confirm my rough estimate. The critical point when measuring SC-cut crystals at room temperature is, that their f(T) response is rather steep at room temperature. There even minor temperature variations during the sweep (or between two sweeps) will cause a shift of the

Re: [time-nuts] Are there SC-crystals out there in the wild that are not Overtone?

Basically you are right. One of the problem is, that SC-cut crystals possess a strong "B-mode" resonance just 9% above the desired stable "C-mode". The B-mode has a similar or even a bit lower resistance than the C-mode, and has a temperature coefficient of -30 ppm/K. It is a temperature sensing

Re: [time-nuts] Are there SC-crystals out there in the wild that are not Overtone?

Am 28.02.20 um 11:34 schrieb Attila Kinali: Yes, but how many of us can build a time-nuts quality oscillator? I'm still lacking that paper/book that teaches me how to build a high stability oscillator. Especially if you see THIS in a tutorial and 5 cm below the OOOH so precise phase noise

Re: [time-nuts] Are there SC-crystals out there in the wild that are not Overtone?

Hi > On Feb 28, 2020, at 9:33 AM, jimlux wrote: > > On 2/28/20 2:34 AM, Attila Kinali wrote: >> On Thu, 27 Feb 2020 08:45:16 -0800 >> "Richard (Rick) Karlquist" wrote: >>> OTOH, you could build a simple Colpitts >>> oscillator and see where it oscillates. >>> That's what they did back in the

Re: [time-nuts] Are there SC-crystals out there in the wild that are not Overtone?

On 2/28/20 2:34 AM, Attila Kinali wrote: On Thu, 27 Feb 2020 08:45:16 -0800 "Richard (Rick) Karlquist" wrote: OTOH, you could build a simple Colpitts oscillator and see where it oscillates. That's what they did back in the dark ages. Any time nut should be up for that. Yes, but how many of

Re: [time-nuts] Are there SC-crystals out there in the wild that are not Overtone?

Well said, been looking for this « tutorial» eagerly myself too. GC. > Le 28 févr. 2020 à 11:35, Attila Kinali a écrit : > > On Thu, 27 Feb 2020 08:45:16 -0800 > "Richard (Rick) Karlquist" wrote: > >> OTOH, you could build a simple Colpitts >> oscillator and see where it oscillates. >>

Re: [time-nuts] Are there SC-crystals out there in the wild that are not Overtone?

Reference on high quality crystal oscillators: On Fri, Feb 28, 2020 at 11:35 AM Attila Kinali wrote: > > On Thu, 27 Feb 2020 08:45:16 -0800 > "Richard (Rick) Karlquist" wrote: > > > OTOH, you could build a simple Colpitts > >

Re: [time-nuts] Are there SC-crystals out there in the wild that are not Overtone?

That's not relevant. The idea is to see what frequency the crystal oscillates at not to build a high stability oscillator. If can be made to oscillate at a frequency somewhere around 5MHz/3 then its likely a third overtone crystal. Bruce > On 28 February 2020 at 23:34 Attila Kinali wrote: > >

Re: [time-nuts] Are there SC-crystals out there in the wild that are not Overtone?

Hi A, but did you then whip up a batch of ammonium bifluoride to clean them up after playing with the grinding compound? :) They figured that part out part way through WWII. The lack proper post grind etch just about had all the radios out there out of service. Bob > On Feb 27, 2020,

Re: [time-nuts] Are there SC-crystals out there in the wild that are not Overtone?

Been there; done that! Rick N6RK On 2/27/2020 12:15 PM, David Van Horn via time-nuts wrote: I remember opening up those military crystals and sanding them down with Ajax cleaner to raise the frequency or rubbing a little solder on the plate to lower it for CW transmitters. High school days.

Re: [time-nuts] Are there SC-crystals out there in the wild that are not Overtone?

Hi The crystal industry in the US went from a couple of outfits (mostly in PA) making < a hundred a month in the 1930’s, to a massive bunch of outfits during WWII. Most were turning out a couple hundred an hour. Much of that collapsed when the war ended and the demand went away. A few

Re: [time-nuts] Are there SC-crystals out there in the wild that are not Overtone?

I remember opening up those military crystals and sanding them down with Ajax cleaner to raise the frequency or rubbing a little solder on the plate to lower it for CW transmitters. High school days.  -- David VanHorn Lead Hardware Engineer Backcountry Access, Inc. 2820 Wilderness Pl, Unit H

Re: [time-nuts] Are there SC-crystals out there in the wild that are not Overtone?

I seem to recall that crystals for frequency control (on a commercial basis) were sort of a post WW2 thing (partly because of developments in piezo hydrophones for sonar) Crystals for radios were well established pre-WWII. There was an FCS paper ~30 years ago about the WWII quartz

Re: [time-nuts] Are there SC-crystals out there in the wild that are not Overtone?

On 2/27/20 8:45 AM, Richard (Rick) Karlquist wrote: OTOH, you could build a simple Colpitts oscillator and see where it oscillates. That's what they did back in the dark ages. Any time nut should be up for that. Rick N6RK But does a deForest Audion (ref Colpitts patent 1624537 1918) have

Re: [time-nuts] Are there SC-crystals out there in the wild that are not Overtone?

Am 27.02.20 um 17:45 schrieb Richard (Rick) Karlquist: OTOH, you could build a simple Colpitts oscillator and see where it oscillates. That's what they did back in the dark ages. Any time nut should be up for that. 5.000 MHz. That was easy. It used to be in something Colpitts-like for 30

Re: [time-nuts] Are there SC-crystals out there in the wild that are not Overtone?

On 2/27/20 10:45, Richard (Rick) Karlquist wrote: > OTOH, you could build a simple Colpitts > oscillator and see where it oscillates. > That's what they did back in the dark > ages. > > Any time nut should be up for that. I was going to suggest pumping it with white noise and then doing a long FFT

Re: [time-nuts] Are there SC-crystals out there in the wild that are not Overtone?

OTOH, you could build a simple Colpitts oscillator and see where it oscillates. That's what they did back in the dark ages. Any time nut should be up for that. Rick N6RK On 2/27/2020 5:35 AM, Bob kb8tq wrote: Hi Ok, so just to run the math: 5 MHz / 2.9 = 1.724 MHz If the Q at the

Re: [time-nuts] Are there SC-crystals out there in the wild that are not Overtone?

If you start off viewing the crystal in series (S21) I believe that you'll be able to see some response far enough away from the resonance to make it easier to find. Dana On Thu, Feb 27, 2020 at 9:39 AM Magnus Danielson wrote: > Hi, > > Even if my VNA steps in 1 Hz if I ask it kindly, it can

Re: [time-nuts] Are there SC-crystals out there in the wild that are not Overtone?

Hi, Even if my VNA steps in 1 Hz if I ask it kindly, it can be a bit teadious work to find it. Cheers, Magnus On 2020-02-27 14:35, Bob kb8tq wrote: > Hi > > Ok, so just to run the math: > > 5 MHz / 2.9 = 1.724 MHz > > If the Q at the fundamental is 500K (a wild guess) then 1.724 MHz / 500,000 =

Re: [time-nuts] Are there SC-crystals out there in the wild that are not Overtone?

Hi Ok, so just to run the math: 5 MHz / 2.9 = 1.724 MHz If the Q at the fundamental is 500K (a wild guess) then 1.724 MHz / 500,000 = 3.4 Hz In a world where a synthesized sweeper *might* be stepping in 10Hz steps, that’s an easy one to miss. Bob > On Feb 26, 2020, at 11:40 PM, Bernd

Re: [time-nuts] Are there SC-crystals out there in the wild that are not Overtone?

Am 26.02.20 um 15:22 schrieb Attila Kinali via time-nuts: Do you know what the two coils/transformers that were glued to the outside of the inner oven were for? I guess they are part of the 5 -> 10 MHz doubler Bernd Neubig has written a few documents on how to measure crystals properly,

Re: [time-nuts] Are there SC-crystals out there in the wild that are not Overtone?

Hoi Gerhard! On Wed, 26 Feb 2020 01:42:11 +0100 Gerhard Hoffmann via time-nuts wrote: > Pics are there: > > < > https://www.flickr.com/photos/137684711@N07/49585174873/in/album-72157662535945536/ > >    > Nice pictures! Thanks! Do you know what the two coils/transformers that were glued

Re: [time-nuts] Are there SC-crystals out there in the wild that are not Overtone?

Hi There certainly are fundamental SC’s out there. SC’s typically have motional resistances above 50 ohms. This usually makes transmission a better way to look for this or that resonance than impedance. Bob > On Feb 25, 2020, at 7:42 PM, Gerhard Hoffmann via time-nuts > wrote: > > I had

[time-nuts] Are there SC-crystals out there in the wild that are not Overtone?

I had a Morion MV89A that would stop oscillating when Vtune was more than +600 mV. So I cut it open to recover at least the crystal, for own experiments. Pics are there: < https://www.flickr.com/photos/137684711@N07/49585174873/in/album-72157662535945536/    > and then following the right