1L10 crystal


Joel B Walker
 

Hello all, I am in need of a 900 kHz crystal Tek number 158-0021-00. It is Y450 on the schematic. I tried Walter Shawlee and every other conceivable place to no avail. I have been looking for this for nearly 10 years. Surely there's one out there somewhere. Thanks for looking.


snapdiode
 

If it's used only in an oscillator you have options but if it's used as a narrowband filter, it's bad luck, No one even makes ceramic resonators near those frequencies anymore either.


Carl Hallberg
 

It is an oscillator, not a filter.  It is a quartz xtal, not ceramic.  I have 1L5, 1L10, 1L20 that I don't use anymore.  I may even have 900KHz xtal, but so much junk to look through.  
W9CJH

On Saturday, September 25, 2021, 02:46:09 PM CDT, snapdiode via groups.io <snapdiode=yahoo.com@groups.io> wrote:





If it's used only in an oscillator you have options but if it's used as a narrowband filter, it's bad luck, No one even makes ceramic resonators near those frequencies anymore either.


 

Pardon me if this is a stupid or ignorant question, but couldn't you replace a 900 kHz crystal in an oscillator application with a much higher frequency crystal and a frequency divider/counter, or two oscillators, a mixer, and a notch filter?

-- Jeff Dutky


Harvey White
 

You can, but......

Most crystals produce a sine wave (even when driven by a square wave, which would be normal), so you should match the voltage, waveform, and frequency.  I think I looked into this once, and I think you *can* buy a 900 Khz sinewave source.  I just looked, and the sources generally give a digital output.  Some are resistor programmable (to 1.5%), not what you'd want.

What you could do is to see what the input of the crystal oscillator will take, voltage wise, and what the waveform is.  You could then take a 9.0 Mhz oscillator, do a divide by 5, then divide by 2 (74LS90 equivalent), run that through a low pass filter and that would give you a 900 Khz source.  If THD is going to be a problem, then not much of a solution other than buy a non-functional unit with a crystal, swap parts, and have spare parts for your existing unit.

Harvey

On 9/25/2021 5:32 PM, Jeff Dutky wrote:
Pardon me if this is a stupid or ignorant question, but couldn't you replace a 900 kHz crystal in an oscillator application with a much higher frequency crystal and a frequency divider/counter, or two oscillators, a mixer, and a notch filter?

-- Jeff Dutky





Joel B Walker
 

My goal is to find a crystal if at all possible. I've thought about the methods mentioned here and also in another thread. I would be inclined to think that quite a bit of noise and harmonic rich signals would be introduced into the system that wouldn't be easy to filter out, and would cause the unit to be ineffective on receiving the signals it is supposed to. I would be happy with a new or used crystal, or a CHEAP parts unit, or a lead to a crystal manufacturer that will actually talk to me.


Michael A. Terrell
 

How close does it have to be? A NTSC 3.579545 MHz colorburst crystal
divided by four is 894.886 KHz.
it would be 5,114 Hz low. that is slightly over a half percent error.
Follow that with a good LC or active filter to remove the harmonics.

Another approach is a simple synthesizer with a 100KHz crystal, a 4046
phase detector and a divide by nine counter.
This kit is overkill, but it would give you what you need for about $20.00
https://www.ebay.com/itm/203595593504

I have the schematic, and was considering a surface mount version to make
it much smaller. since I only wanted a single frequency

On Sat, Sep 25, 2021 at 1:28 PM Joel B Walker <joelandjoyce@esinc.net>
wrote:

Hello all, I am in need of a 900 kHz crystal Tek number 158-0021-00. It is
Y450 on the schematic. I tried Walter Shawlee and every other conceivable
place to no avail. I have been looking for this for nearly 10 years. Surely
there's one out there somewhere. Thanks for looking.






Joel B Walker
 

Carl, what would it take to make it worth your while to find one?


Michael A. Terrell
 

14.4 MHz divided by 16 looks like the simplest source of 900 KHz, followed
by a filter to clean it up.. You could also drive a 1:1 pll to give a
clean output. I spent a lot of time working with low phase noise
synthesizers at Microdyne. These were multiple band segments that
overlapped to keep each segment smaller and cleaner.. A trap to remove the
reference frequency is needed to reduce phase noise, and leakthrough. These
were used to receive deep space Telemetry signals.

On Sat, Sep 25, 2021 at 9:53 PM Michael A. Terrell via groups.io
<terrell.michael.a=gmail.com@groups.io> wrote:

How close does it have to be? A NTSC 3.579545 MHz colorburst crystal
divided by four is 894.886 KHz.
it would be 5,114 Hz low. that is slightly over a half percent error.
Follow that with a good LC or active filter to remove the harmonics.

Another approach is a simple synthesizer with a 100KHz crystal, a 4046
phase detector and a divide by nine counter.
This kit is overkill, but it would give you what you need for about $20.00
https://www.ebay.com/itm/203595593504

I have the schematic, and was considering a surface mount version to make
it much smaller. since I only wanted a single frequency

On Sat, Sep 25, 2021 at 1:28 PM Joel B Walker <joelandjoyce@esinc.net>
wrote:

Hello all, I am in need of a 900 kHz crystal Tek number 158-0021-00. It
is
Y450 on the schematic. I tried Walter Shawlee and every other conceivable
place to no avail. I have been looking for this for nearly 10 years.
Surely
there's one out there somewhere. Thanks for looking.










Ed Breya
 

This seems like deja vu all over again. I think there was a lengthy discussion of this same sort of thing for a 1L10 or maybe 1L20 or 1L30, within the past couple years. You may want to look back in the archives to see nearly the exact same story played out, and the options considered.

Ed


Carl Hallberg
 

Ed,
I read some of the past articles.  One person suggested removing the case from an HC6 crystal and lowering the frequency by adding material, but those are sealed units with silver "plating" on the quartz.  If the package isn't back filled with non-oxygen gas or vacuum, silver will oxidize and make it worthless. I will see if I can find a 900KHz  and measure it on Saunders Impedance Meter.  I used to work for company that ordered low freq blanks and sputtered silver on xtal after brought into correct freq.  Too much junk to go through.  Need to get rid of much.  Talk about deja vu, how about the 7S14.  Much info has been documented and shown in the past without being referenced.  Not you.  Repeat, repeat, repeat.  
Carl  (W9CJH)

On Saturday, September 25, 2021, 09:54:31 PM CDT, Ed Breya via groups.io <edbreya=yahoo.com@groups.io> wrote:





This seems like deja vu all over again. I think there was a lengthy discussion of this same sort of thing for a 1L10 or maybe 1L20 or 1L30, within the past couple years. You may want to look back in the archives to see nearly the exact same story played out, and the options considered.

Ed


Carl Hallberg
 

Joel,
I will measure the xtal in the 1L10 and see what I have in the junk.  If I find one, you can have it for postage.  I thought I saw one in the past.
Carl

On Saturday, September 25, 2021, 09:43:32 PM CDT, Joel B Walker <joelandjoyce@esinc.net> wrote:





Carl, what would it take to make it worth your while to find one?


John Gord
 

Joel,
Bomar claims to still make custom crystals. This model seems to cover the proper frequency range:
http://bomarcrystal.com/hc_51Ucrystal.html

--John Gord

On Sat, Sep 25, 2021 at 10:28 AM, Joel B Walker wrote:


Hello all, I am in need of a 900 kHz crystal Tek number 158-0021-00. It is
Y450 on the schematic. I tried Walter Shawlee and every other conceivable
place to no avail. I have been looking for this for nearly 10 years. Surely
there's one out there somewhere. Thanks for looking.


Tom Bowers
 

" Hello all, I am in need of a 900 kHz crystal Tek number 158-0021-00"

Digikey has a 1.8 MHz crystal. A divide by two circuit in 4000 series CMOS
or your other favorite logic family should be pretty simple.

Tom

On Sat, Sep 25, 2021 at 8:48 PM Michael A. Terrell <
terrell.michael.a@gmail.com> wrote:

14.4 MHz divided by 16 looks like the simplest source of 900 KHz, followed
by a filter to clean it up.. You could also drive a 1:1 pll to give a
clean output. I spent a lot of time working with low phase noise
synthesizers at Microdyne. These were multiple band segments that
overlapped to keep each segment smaller and cleaner.. A trap to remove the
reference frequency is needed to reduce phase noise, and leakthrough. These
were used to receive deep space Telemetry signals.

On Sat, Sep 25, 2021 at 9:53 PM Michael A. Terrell via groups.io
<terrell.michael.a=gmail.com@groups.io> wrote:

How close does it have to be? A NTSC 3.579545 MHz colorburst crystal
divided by four is 894.886 KHz.
it would be 5,114 Hz low. that is slightly over a half percent error.
Follow that with a good LC or active filter to remove the harmonics.

Another approach is a simple synthesizer with a 100KHz crystal, a 4046
phase detector and a divide by nine counter.
This kit is overkill, but it would give you what you need for about
$20.00
https://www.ebay.com/itm/203595593504

I have the schematic, and was considering a surface mount version to make
it much smaller. since I only wanted a single frequency

On Sat, Sep 25, 2021 at 1:28 PM Joel B Walker <joelandjoyce@esinc.net>
wrote:

Hello all, I am in need of a 900 kHz crystal Tek number 158-0021-00. It
is
Y450 on the schematic. I tried Walter Shawlee and every other
conceivable
place to no avail. I have been looking for this for nearly 10 years.
Surely
there's one out there somewhere. Thanks for looking.














Joel B Walker
 

Thanks Carl for looking. I anxiously await your answer.
As far as Bomar is concerned, I have tried to contact them numerous times with no response. Apparently they don't respond to emails. Maybe I will try contacting them by phone.
Yes, I am the creator of the previous thread referenced to. Sorry, perhaps I should have revived that thread.