Everything You Need To Know To Find The Best he-49u crystal quartz resonator
HC-49U vs HC-49S crystals - Qrp-Tech
chuck adams
You will get efficient and thoughtful service from Huixun.
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Paul, NA5N, makes a good point on frequency range between the two form
factors.
The HC-49U crystal form factor operates in the shear mode.
The HC-49S crystal form factor operates in the flexure mode.
I have found that the R_s (series resistance) of the HC-49S
is on the order of 3-4 times that for the same frequency
than that of the HC-49U.
The board I've got coming from China is the Colpitts
crystal oscillator for crystal matching. I've got a
metering circuit for checking activity. I'm going to
use the critter to do some more research between
the U vs S form factor. The boards may be here
by Friday or Saturday if DHL delivers on the weekend.
Unfortunately, I've got some bad news for you.
It is my belief, due to cost of manufacturing, that
the HC-49U form factor is going the way of a lot
of species. Get 'em while you can. Have you
checked ebay lately on crystals. Look for the
ratio of the availability of the two.
FYI
chuck, k7qo
Michael VE3WMB
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All manufactured components are not created equally so if we can come up with a way to
better characterize bulk HC-49S crystals to get reasonable
performing matched sets for IF filters etc then that would be great.
I ordered 100
HC-49S crystals for $10 so at that price I don't care if only 10 percent are good for this application, but it would be great if we are
able to separate the "wheat from the chaff".
We Hams are good at this sort of thing. I remember that the early AMSAT satellites used off-the-shelf
NiCad cells that were purchased cheaply in bulk. A local Ham, Larry Kaiser, VA3LK (SK) came up with an extensive
test procedure and Mil-Spec certified a small subset of the purchased cells for use in these satellites, saving Amsat
a pile of money.
Michael VE3WMB
While the HC-49S are dirt cheap, the few HC-49U crystals on eBay are going for comparatively a lot more money. It would be good if we could figure out a way to use HC-49S.
Michael VE3WMB
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I had some further thoughts regarding the use of HC49-S crystals (the compact ones) and how to address some of
the concerns that Paul, NA5N raised about the suitability of these for the NC40A, based on his past experiences.
I was thinking about other things other than frequency that we could measure and
it occurred to me that it would be easy to look at the amplitude of the output of the Colpitts Oscillator used for Frequency
matching the crystals.
This could be done at the same time as the frequency measurement using an oscilloscope or maybe
even an RF Probe. Surely "more active crystals" are better for this application that "less active" crystals and that should
translate to more power out of the oscillator, which should be measurable.
The other thought was to build a simple VXO (ala W1FB) and directly measure how much the individual crystals in a
Frequency matched set can be pulled, and create a subset of hopefully the "best" Crystals for a given Frequency-matched
set.
I am not an expert in crystal physics, but it would be an interesting exercise to see if there is any direct correlation between
the relative output level of the Colpits oscillator and the "bendability" of a given crystal (i.e. are the more active crystals the
ones most easily pulled off frequency?). My gut feeling is that this might be the case. Still it would be interesting to do this
experiment and record the results for future reference.
Thoughts ?? Would it be worth the extra effort? Am I being overly OCD ?
Obviously I have too much time on my hands, waiting for my 100 X 4. Mhz HC49-S crystals to arrive from China ;-)
Cheers
--
Michael VE3WMB / VA2NB
Tom, N8TPN
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Take a look at KC9ON's page about pulling and bending crystals...
John is a member of this group...he and I are putting together a NC40A group-build for our club, so I'm sure he'd be happy to discuss his experiences in greater depth.
Sorry, I can't seem to figure out how to embed hyperlinks here, so you will have to cut and paste the above address into your browser.
73
Tom
N8TPN
Michael,Take a look at KC9ON's page about pulling and bending crystals... https://kc9on.com/ham-radio/crystals/svxo/ John is a member of this group...he and I are putting together a NC40A group-build for our club, so I'm sure he'd be happy to discuss his experiences in greater depth.Sorry, I can't seem to figure out how to embed hyperlinks here, so you will have to cut and paste the above address into your browser.73TomN8TPN
Rahul Srivastava
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Wes Hayward has summarised the difference between both the packages in his excellent papers here:
http://w7zoi.net/xtalmod.pdf
It is variation in Lm value between HC 49U and HC 49S that we should be more concerned with while making filters as it is one of the critical parameter.
73 On Thursday 23 November , 9:31:05 PM IST, N8TPN <tsadamski@...> wrote:
Michael,
Take a look at KC9ON's page about pulling and bending crystals...
John is a member of this group...he and I are putting together a NC40A group-build for our club, so I'm sure he'd be happy to discuss his experiences in greater depth.
Sorry, I can't seem to figure out how to embed hyperlinks here, so you will have to cut and paste the above address into your browser.
73
Tom
N8TPN
Hi!Wes Hayward has summarised the difference between both the packages in his excellent papers here:It is variation in Lm value between HC 49U and HC 49S that we should be more concerned with while making filters as it is one of the critical parameter.73 On Thursday 23 November , 9:31:05 PM IST, N8TPN wrote:Michael,Take a look at KC9ON's page about pulling and bending crystals... https://kc9on.com/ham-radio/crystals/svxo/ John is a member of this group...he and I are putting together a NC40A group-build for our club, so I'm sure he'd be happy to discuss his experiences in greater depth.Sorry, I can't seem to figure out how to embed hyperlinks here, so you will have to cut and paste the above address into your browser.73TomN8TPN
va3rr#
I've been looking on Ebay, and HC-49U xtals for 4.915 or 4. MHz are slim pickings indeed.
I do see one vendor selling qty 100 4.MHz xtals for considerably cheaper - I note the SW40 used 4 MHz xtals and low-side injection so I'm guessing that I could probably build my NC40 to use a lower IF without too many unforeseen consequences?
Paul NA5N
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I am not an expert in crystal physics, but it would be an interesting exercise to see if there is any direct correlation betweenMichael,
the relative output level of the Colpits oscillator and the "bendability" of a given crystal
We all have data sheets, websites, articles on crystals, etc. at our disposal to read and study. But, NOTHING replaces good old fashioned "bench testing." That's how things really work in the real world, so your tests would be valuable for your own edification as well as for others here on the group. So data from your tests would be very valuable.
I did my tests on the HC-49S crystals over 10 years ago. What I measured was the smaller crystals resulted in a very high motional inductance, Lm, compared to the larger HC49U, no doubt due to the smaller crystal size. Like 0.1Hy as I recall. Thus, adding a few tens of uH as a pulling element is still a fraction of the overall Lm you're trying to effect. Perhaps there are differences in the parameters of the small crystals of those manufactured today that your tests might reveal.
I also do not recall how "active" the HC-49S were in an oscillator circuit compared to the HC-49U, so that, too, would be valuable information. So I'm sure your tests would have great value to those on this group. Let us know what you find.
72, Paul NA5N
Michael Babineau writes:Michael,We all have data sheets, websites, articles on crystals, etc. at our disposal to read and study. But, NOTHING replaces good old fashioned "bench testing." That's how things really work in the real world, so your tests would be valuable for your own edification as well as for others here on the group. So data from your tests would be very valuable.I did my tests on the HC-49S crystals over 10 years ago. What I measured was the smaller crystals resulted in a very high motional inductance, Lm, compared to the larger HC49U, no doubt due to the smaller crystal size. Like 0.1Hy as I recall. Thus, adding a few tens of uH as a pulling element is still a fraction of the overall Lm you're trying to effect. Perhaps there are differences in the parameters of the small crystals of those manufactured today that your tests might reveal.I also do not recall how "active" the HC-49S were in an oscillator circuit compared to the HC-49U, so that, too, would be valuable information. So I'm sure your tests would have great value to those on this group. Let us know what you find.72, Paul NA5N
16 parameters you need to know before buying frequency ...
A quartz crystal (crystal or Xtal) is a resonant element made by using the piezoelectric effect of a quartz crystal, which is a quartz wafer with electrodes and a housing package.It is also known as quartz oscillator or crystal resonator.It is a passive component with no active components and requires an external circuit to generate oscillation.This is a passive component,also known as a passive crystal resonator in China.If IC is compared to the brain of human body, then crystal resonator is like the heart of the brain.
Generally speaking we divide crystal oscillators into resonators and oscillators, also known as passive and active crystals,the abbreviation is usually used XTAL and OSC to indicate,this article I mainly talk about passive resonators,and passive resonators we are usually divided into SMD and DIP two different types.For many buyers,they also need to know more about the resonator knowledge,the following I will write 16 specific parameters about the resonator,so as to help buyers better understand the product, the correct understanding and purchase the product,write this article is only my entry into the industry of a self-learning,the knowledge written are some of the most basic parameters of the product, if there are individual errors, please advise Correction.
1.Size
&#; Common SMD crystal model (passive): SMD SMD SMD SMD SMD SMD SMD, this naming we are based on its a length and width of the size, so named, such as SMD, then its length is 1.6mm, width is 1.2mm, due to its appearance is For example, SMD, then its length is 1.6mm, width is 1.2mm, because its appearance is smooth and no corner, we call it SMD.
&#; Common inline crystal model (passive): HC-49S HC-49SG HC-49SMD HC-49U UM-1 UM-5, we also call it DIP type, because it is relatively larger than SMD type products and has several more leads, so we call it inline type crystal.
&#; Common cylindrical crystal type (passive): what we usually call 3*8 2*6, this type of product is not commonly used now and gradually withdrawn.
2.Frequency Range
This refers to the frequency specified in the crystal component specification, i.e.,the ideal operating frequency desired by the user during circuit design and component selection.For resonator frequency determination also needs the customer's own product on the application, through the customer's own R & D team matching and testing,the customer itself through the R & D test team will give a definite frequency.
3.Load Capacitance (CL)
The effective external capacitance that determines the load resonant frequency FL together with the crystal element. The CL in the crystal element specification is a test condition as well as a condition of use, and this value can be adjusted appropriately according to the situation in the specific use of the user to fine-tune the actual operating frequency of the FL (i.e.the manufacturing tolerance of the crystal can be adjusted).
4.Frequency Tolerence At 25&#;
The maximum allowable deviation of the operating frequency relative to the nominal frequency at the reference temperature.It is often expressed in ppm.
5.Frequency Stability Over Temperature Range
The allowable deviation of the operating frequency in the whole temperature range relative to the working frequency at the reference temperature. Commonly expressed in ppm.
6.Aging Rate
It refers to the frequency drift caused by time under the specified conditions.This indicator is necessary for precision crystals, but it does not have clear test conditions,but by the manufacturer through the continuous supervision of all products with planned sampling,some crystal components may be worse than the specified level, which is allowed.The best solution to the aging problem can only be found in close consultation between the manufacturer and the user.
7.Resonance Resistance (RR)
The equivalent resistance of the crystal element at the resonant frequency is approximately equal to the so-called dynamic resistance R1 or equivalent series resistance (ESR) of the crystal when the effect of C0 is not considered.This parameter controls the quality factor of the crystal element and determines the oscillation level of the crystal in the applied circuit,thus influencing the stability of the crystal and whether it can oscillate ideally.Therefore,it is an important indicator parameter of the crystal element.In general,the smaller the frequency of the crystal chosen for a given frequency,the higher the average value of ESR may be.
8.Load Resonance Resistance (RL)
Refers to the resistance of the crystal element in series with the specified external capacitor at the load resonant frequency FL.For a given crystal element,the value of its load resonance resistance depends on the value of the load capacitance working with the element,and the resonance resistance after the series load capacitance is always greater than the resonance resistance of the crystal element itself.
9.Resonant Frequency (FR)
Refers to the lower of the two frequencies at which the electrical impedance of the crystal element is resistive under specified conditions. According to the equivalent circuit, when the effect of C0 is not considered,the FR is determined by C1 and L1 and is approximately equal to the so-called series resonant frequency.
10.Load Resonant Frequency (FL)
Refers to one of the two frequencies when the crystal element is connected in series or parallel with a load capacitor under specified conditions and its combined impedance is presented as resistive.When the load capacitor is connected in series,the FL is the lower of the two frequencies;when the load capacitor is connected in parallel,the FL is the higher of the two frequencies.For a given value of load capacitance (CL),the two frequencies are the same for practical effect;and this frequency is the actual frequency that the crystal exhibits in the circuit for most applications,and is the test parameter that the manufacturer uses to meet the user's requirements for the product to meet the nominal frequency.
11.Static Capacitance(CO)
Equivalent circuit capacitance in the static arm.Its size mainly depends on the electrode area,wafer thickness and wafer processing technology.
12.Dynamic capacitance (C1)
The capacitance in the dynamic arm of the equivalent circuit.Its size mainly depends on the electrode area,in addition to the parallelism of the wafer and the size of the trim amount.
13.Level Of Drive
It is a measure of the excitation conditions applied to the crystal element, expressed in terms of dissipated power.
14.SPDB
The difference of parasitic frequency compared to the main frequency level when measured with 12.5ohm test head.
15.DLD2
The difference between the maximum value and the minimum value of the load resonance resistance at different excitation levels.
16.RLD2
The maximum Rr value under different excitation power.
Of course,there are many more parameters of the quartz crystal,but for us to just master the above will do, for most purchases at present,have clearly obtained especially the information of the first seven parameters above,the information of these first seven parameters is also the information that many purchases are looking for when buying,for professional and technical people,they will know more knowledge of the parameters,so this article is also just for the general public, finally thank you for reading.
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