Richard (Rick) Karlquist said: > We actually used the upper turnover because the E1938 had to operate at > ambient up 85 degrees. BTW, the E1938 crystals had to be calibrated for > 10.000000 MHz at series resonance, unlike the 10811 crystals which were > calibrated for 20 pF (IIRC). How big is the difference between series and 20pF compared to the tuning range? -- These are my opinions. I hate spam.

It is hard to answer your question. The tuning range depends on the varactor(s) used in the respective oscillators, and the range of the tuning voltages. I think I could roughly say from memory that putting in a crystal meant for the other oscillator would probably result in not being able to reach 10.000000 MHz. Or just barely reaching it and having no aging margin. I had to apply a lot of arm twisting to Jack Kusters to get him to make the series resonant (at 10 MHz) crystals. I made sure that this was really necessary before going to war on it. Rick N6RK On 8/14/2022 3:35 PM, Hal Murray via time-nuts wrote: > > Richard (Rick) Karlquist said: >> We actually used the upper turnover because the E1938 had to operate at >> ambient up 85 degrees. BTW, the E1938 crystals had to be calibrated for >> 10.000000 MHz at series resonance, unlike the 10811 crystals which were >> calibrated for 20 pF (IIRC). > > How big is the difference between series and 20pF compared to the tuning range? > >

Hi One “interesting” way to look at this is a “delta F” test. It’s based on a system that (essentially) always measures things at series. You put the (maybe) 20 pf load cap in series with the crystal and zip off it goes to measure the net result of the crystal at a 20 pf load. Typically you did this by pushing a paddle on a fixture. Yes that’s very specific to one rig up. Turns out that Motorola decided it was a fun thing and we tested a *lot* of crystals that way. It’s been “a while” … but .. fundamental crystals came in at > 400 ppm. Third overtones might be around 30 ppm. Fifth overtones might be around 3 to 5 ppm. No this isn’t for the same crystal or even the same crystal package. It also isn’t for SC cuts, these all where AT’s. … and yes, if I could remember the name if the UK outfit that made the test heads, I’d give them credit for their cute little gizmo. One interesting outcome of testing this way was to spec crystals as some number of PPM off series rather than with a load. Changing the load cap in the fixture was “not done”. AFIK that was very specific to internal Motorola documents. The only time I saw it used elsewhere was on crystals that operated below series. Bob > On Aug 17, 2022, at 5:28 AM, Richard (Rick) Karlquist via time-nuts <time-nuts@lists.febo.com> wrote: > > It is hard to answer your question. The tuning range > depends on the varactor(s) used in the respective > oscillators, and the range of the tuning voltages. > I think I could roughly say from memory that putting > in a crystal meant for the other oscillator would > probably result in not being able to reach 10.000000 > MHz. Or just barely reaching it and having no > aging margin. I had to apply a lot of arm twisting > to Jack Kusters to get him to make the series > resonant (at 10 MHz) crystals. I made sure that > this was really necessary before going to war on it. > > Rick N6RK > > On 8/14/2022 3:35 PM, Hal Murray via time-nuts wrote: >> Richard (Rick) Karlquist said: >>> We actually used the upper turnover because the E1938 had to operate at >>> ambient up 85 degrees. BTW, the E1938 crystals had to be calibrated for >>> 10.000000 MHz at series resonance, unlike the 10811 crystals which were >>> calibrated for 20 pF (IIRC). >> How big is the difference between series and 20pF compared to the tuning range? > _______________________________________________ > time-nuts mailing list -- time-nuts@lists.febo.com > To unsubscribe send an email to time-nuts-leave@lists.febo.com

Hi Thanks to a bit of off list coaching from those who’s memory (obviously) better than mine :) : This is the magic test set that Motorola (and many others) got pretty heavily into: https://isolalab.com/pinetwork.html <https://isolalab.com/pinetwork.html> The gizmo is right at the top of the page. There’s a nice paragraph next to it and a diagram of what’s inside. The original outfit that made it ( Cathodeon / Pye ) has been out of business for quite a while. They apparently made the fixture to support their crystal manufacturing business. Just how many fixtures they sold to their competitors …. no idea. Bob > On Aug 17, 2022, at 8:17 AM, Bob kb8tq <kb8tq@n1k.org> wrote: > > Hi > > One “interesting” way to look at this is a “delta F” test. > It’s based on a system that (essentially) always measures > things at series. You put the (maybe) 20 pf load cap in series > with the crystal and zip off it goes to measure the net result > of the crystal at a 20 pf load. > > Typically you did this by pushing a paddle on a fixture. Yes > that’s very specific to one rig up. Turns out that Motorola > decided it was a fun thing and we tested a *lot* of crystals > that way. It’s been “a while” … but .. fundamental crystals > came in at > 400 ppm. Third overtones might be around > 30 ppm. Fifth overtones might be around 3 to 5 ppm. > > No this isn’t for the same crystal or even the same crystal > package. It also isn’t for SC cuts, these all where AT’s. > > … and yes, if I could remember the name if the UK outfit > that made the test heads, I’d give them credit for their cute > little gizmo. > > One interesting outcome of testing this way was to spec > crystals as some number of PPM off series rather than > with a load. Changing the load cap in the fixture was “not > done”. AFIK that was very specific to internal Motorola > documents. The only time I saw it used elsewhere was > on crystals that operated below series. > > Bob > >> On Aug 17, 2022, at 5:28 AM, Richard (Rick) Karlquist via time-nuts <time-nuts@lists.febo.com> wrote: >> >> It is hard to answer your question. The tuning range >> depends on the varactor(s) used in the respective >> oscillators, and the range of the tuning voltages. >> I think I could roughly say from memory that putting >> in a crystal meant for the other oscillator would >> probably result in not being able to reach 10.000000 >> MHz. Or just barely reaching it and having no >> aging margin. I had to apply a lot of arm twisting >> to Jack Kusters to get him to make the series >> resonant (at 10 MHz) crystals. I made sure that >> this was really necessary before going to war on it. >> >> Rick N6RK >> >> On 8/14/2022 3:35 PM, Hal Murray via time-nuts wrote: >>> Richard (Rick) Karlquist said: >>>> We actually used the upper turnover because the E1938 had to operate at >>>> ambient up 85 degrees. BTW, the E1938 crystals had to be calibrated for >>>> 10.000000 MHz at series resonance, unlike the 10811 crystals which were >>>> calibrated for 20 pF (IIRC). >>> How big is the difference between series and 20pF compared to the tuning range? >> _______________________________________________ >> time-nuts mailing list -- time-nuts@lists.febo.com >> To unsubscribe send an email to time-nuts-leave@lists.febo.com >

Hi: IEC 444 is a PI-Netowrk measurement method for crystals.  It is supposed to me more accurate than the method that uses a physical CL. The HP 41900A has the look and feel of the linked PI-Network fixture so may just be a re-branded version. https://prc68.com/I/4395A.shtml#E5100 -- Have Fun, Brooke Clarke https://www.PRC68.com axioms: 1. The extent to which you can fix or improve something will be limited by how well you understand how it works. 2. Everybody, with no exceptions, holds false beliefs. -------- Original Message -------- > Hi > > Thanks to a bit of off list coaching from those who’s memory (obviously) > better than mine :) : > > This is the magic test set that Motorola (and many others) got pretty > heavily into: > > https://isolalab.com/pinetwork.html <https://isolalab.com/pinetwork.html> > > The gizmo is right at the top of the page. There’s a nice paragraph next > to it and a diagram of what’s inside. > > The original outfit that made it ( Cathodeon / Pye ) has been out of business > for quite a while. They apparently made the fixture to support their > crystal manufacturing business. Just how many fixtures they sold to > their competitors …. no idea. > > Bob > >> On Aug 17, 2022, at 8:17 AM, Bob kb8tq <kb8tq@n1k.org> wrote: >> >> Hi >> >> One “interesting” way to look at this is a “delta F” test. >> It’s based on a system that (essentially) always measures >> things at series. You put the (maybe) 20 pf load cap in series >> with the crystal and zip off it goes to measure the net result >> of the crystal at a 20 pf load. >> >> Typically you did this by pushing a paddle on a fixture. Yes >> that’s very specific to one rig up. Turns out that Motorola >> decided it was a fun thing and we tested a *lot* of crystals >> that way. It’s been “a while” … but .. fundamental crystals >> came in at > 400 ppm. Third overtones might be around >> 30 ppm. Fifth overtones might be around 3 to 5 ppm. >> >> No this isn’t for the same crystal or even the same crystal >> package. It also isn’t for SC cuts, these all where AT’s. >> >> … and yes, if I could remember the name if the UK outfit >> that made the test heads, I’d give them credit for their cute >> little gizmo. >> >> One interesting outcome of testing this way was to spec >> crystals as some number of PPM off series rather than >> with a load. Changing the load cap in the fixture was “not >> done”. AFIK that was very specific to internal Motorola >> documents. The only time I saw it used elsewhere was >> on crystals that operated below series. >> >> Bob >> >>> On Aug 17, 2022, at 5:28 AM, Richard (Rick) Karlquist via time-nuts <time-nuts@lists.febo.com> wrote: >>> >>> It is hard to answer your question. The tuning range >>> depends on the varactor(s) used in the respective >>> oscillators, and the range of the tuning voltages. >>> I think I could roughly say from memory that putting >>> in a crystal meant for the other oscillator would >>> probably result in not being able to reach 10.000000 >>> MHz. Or just barely reaching it and having no >>> aging margin. I had to apply a lot of arm twisting >>> to Jack Kusters to get him to make the series >>> resonant (at 10 MHz) crystals. I made sure that >>> this was really necessary before going to war on it. >>> >>> Rick N6RK >>> >>> On 8/14/2022 3:35 PM, Hal Murray via time-nuts wrote: >>>> Richard (Rick) Karlquist said: >>>>> We actually used the upper turnover because the E1938 had to operate at >>>>> ambient up 85 degrees. BTW, the E1938 crystals had to be calibrated for >>>>> 10.000000 MHz at series resonance, unlike the 10811 crystals which were >>>>> calibrated for 20 pF (IIRC). >>>> How big is the difference between series and 20pF compared to the tuning range? >>> _______________________________________________ >>> time-nuts mailing list -- time-nuts@lists.febo.com >>> To unsubscribe send an email to time-nuts-leave@lists.febo.com > _______________________________________________ > time-nuts mailing list -- time-nuts@lists.febo.com > To unsubscribe send an email to time-nuts-leave@lists.febo.com

Hi In the era that the fixture was used, doing this with an network analyzer wasn’t even a pipe dream. Doing up an adequate set of data with the gear of that era was a long and drawn out process. Getting a measurement with a simple fixture was a second or two. Indeed if 1% on resistance and a tenth of a ppm frequency wasn’t adequate, you might head off to other approaches. Given the make tolerances on the crystals, neither one was a limit to production testing. The biggest limit in reality was the accuracy of the load capacitor. That’s why you never / ever swapped it out. The value that was in there was confirmed by some non-trivially exciting testing with a number of “golden” crystals. Bob > On Aug 19, 2022, at 10:30 AM, Brooke Clarke via time-nuts <time-nuts@lists.febo.com> wrote: > > Hi: > > IEC 444 is a PI-Netowrk measurement method for crystals. It is supposed to me more accurate than the method that uses a physical CL. > The HP 41900A has the look and feel of the linked PI-Network fixture so may just be a re-branded version. > https://prc68.com/I/4395A.shtml#E5100 > > -- > Have Fun, > > Brooke Clarke > https://www.PRC68.com > axioms: > 1. The extent to which you can fix or improve something will be limited by how well you understand how it works. > 2. Everybody, with no exceptions, holds false beliefs. > > -------- Original Message -------- >> Hi >> >> Thanks to a bit of off list coaching from those who’s memory (obviously) >> better than mine :) : >> >> This is the magic test set that Motorola (and many others) got pretty >> heavily into: >> >> https://isolalab.com/pinetwork.html <https://isolalab.com/pinetwork.html> >> >> The gizmo is right at the top of the page. There’s a nice paragraph next >> to it and a diagram of what’s inside. >> >> The original outfit that made it ( Cathodeon / Pye ) has been out of business >> for quite a while. They apparently made the fixture to support their >> crystal manufacturing business. Just how many fixtures they sold to >> their competitors …. no idea. >> >> Bob >> >>> On Aug 17, 2022, at 8:17 AM, Bob kb8tq <kb8tq@n1k.org> wrote: >>> >>> Hi >>> >>> One “interesting” way to look at this is a “delta F” test. >>> It’s based on a system that (essentially) always measures >>> things at series. You put the (maybe) 20 pf load cap in series >>> with the crystal and zip off it goes to measure the net result >>> of the crystal at a 20 pf load. >>> >>> Typically you did this by pushing a paddle on a fixture. Yes >>> that’s very specific to one rig up. Turns out that Motorola >>> decided it was a fun thing and we tested a *lot* of crystals >>> that way. It’s been “a while” … but .. fundamental crystals >>> came in at > 400 ppm. Third overtones might be around >>> 30 ppm. Fifth overtones might be around 3 to 5 ppm. >>> >>> No this isn’t for the same crystal or even the same crystal >>> package. It also isn’t for SC cuts, these all where AT’s. >>> >>> … and yes, if I could remember the name if the UK outfit >>> that made the test heads, I’d give them credit for their cute >>> little gizmo. >>> >>> One interesting outcome of testing this way was to spec >>> crystals as some number of PPM off series rather than >>> with a load. Changing the load cap in the fixture was “not >>> done”. AFIK that was very specific to internal Motorola >>> documents. The only time I saw it used elsewhere was >>> on crystals that operated below series. >>> >>> Bob >>> >>>> On Aug 17, 2022, at 5:28 AM, Richard (Rick) Karlquist via time-nuts <time-nuts@lists.febo.com> wrote: >>>> >>>> It is hard to answer your question. The tuning range >>>> depends on the varactor(s) used in the respective >>>> oscillators, and the range of the tuning voltages. >>>> I think I could roughly say from memory that putting >>>> in a crystal meant for the other oscillator would >>>> probably result in not being able to reach 10.000000 >>>> MHz. Or just barely reaching it and having no >>>> aging margin. I had to apply a lot of arm twisting >>>> to Jack Kusters to get him to make the series >>>> resonant (at 10 MHz) crystals. I made sure that >>>> this was really necessary before going to war on it. >>>> >>>> Rick N6RK >>>> >>>> On 8/14/2022 3:35 PM, Hal Murray via time-nuts wrote: >>>>> Richard (Rick) Karlquist said: >>>>>> We actually used the upper turnover because the E1938 had to operate at >>>>>> ambient up 85 degrees. BTW, the E1938 crystals had to be calibrated for >>>>>> 10.000000 MHz at series resonance, unlike the 10811 crystals which were >>>>>> calibrated for 20 pF (IIRC). >>>>> How big is the difference between series and 20pF compared to the tuning range? >>>> _______________________________________________ >>>> time-nuts mailing list -- time-nuts@lists.febo.com >>>> To unsubscribe send an email to time-nuts-leave@lists.febo.com >> _______________________________________________ >> time-nuts mailing list -- time-nuts@lists.febo.com >> To unsubscribe send an email to time-nuts-leave@lists.febo.com > > _______________________________________________ > time-nuts mailing list -- time-nuts@lists.febo.com > To unsubscribe send an email to time-nuts-leave@lists.febo.com