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With all my recent measurements of CMCs, I've been encouraged by several
readers to put together a procedure for the various measurements I've made
with the HP 8753C, but using the NANOVNAs and SAVER. The attachment is the
first installment which presents a procedure using the NANOs and SAVER to
measure the DM loss through any CMC. It is also useful for measuring other
two-terminal transmissive devices such as filters, attenuators, active
stages, and.......
Have a look at my first cut. I'd invite anyone to make suggestions to make
things clearer and/or correct any errors I've made in the write-up. Have a
read of the attachment.
The next installment will address measuring the bulk CM impedance presented
by the CMCs using the NANOs and SAVER (another day, please) which have been
previously measured using the HP equipment.
Dave - W?LEV
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David, thanks for the good work, but I have one question,?
1.? With all of the equipment and access to the testing site, did you make the measurements at different times and different calibrations?? Sort of defeats the accuracy right off the get go.? In my book any serious engineering comparisons like that, are done at one sitting, N O changes in setup PERIOD.? Sorry, my stick.
Mel, K6KBE
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On Friday, January 29, 2021, 02:25:24 PM PST, David Eckhardt <davearea51a@...> wrote:
With all my recent measurements of CMCs, I've been encouraged by several
readers to put together a procedure for the various measurements I've made
with the HP 8753C, but using the NANOVNAs and SAVER.? The attachment is the
first installment which presents a procedure using the NANOs and SAVER to
measure the DM loss through any CMC.? It is also useful for measuring other
two-terminal transmissive devices such as filters, attenuators, active
stages, and.......
Have a look at my first cut.? I'd invite anyone to make suggestions to make
things clearer and/or correct any errors I've made in the write-up.? Have a
read of the attachment.
The next installment will address measuring the bulk CM impedance presented
by the CMCs using the NANOs and SAVER (another day, please) which have been
previously measured using the HP equipment.
Dave - W?LEV
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Setups HAD to change. The initial measurements were made with the HP 8753C. Those I put out today with the procedure are made using the NANOVNA and SAVER. Of course the setups are DIFFERENT!!!!!! ENTIRELY DIFFERENT INSTRUMENTS!!!!!! Dave - W?LEV On Fri, Jan 29, 2021 at 11:02 PM Mel Farrer via groups.io <farrerfolks= [email protected]> wrote: David, thanks for the good work, but I have one question,
1. With all of the equipment and access to the testing site, did you make
the measurements at different times and different calibrations? Sort of
defeats the accuracy right off the get go. In my book any serious
engineering comparisons like that, are done at one sitting, N O changes in
setup PERIOD. Sorry, my stick.
Mel, K6KBE
On Friday, January 29, 2021, 02:25:24 PM PST, David Eckhardt <
davearea51a@...> wrote:
With all my recent measurements of CMCs, I've been encouraged by several
readers to put together a procedure for the various measurements I've made
with the HP 8753C, but using the NANOVNAs and SAVER. The attachment is the
first installment which presents a procedure using the NANOs and SAVER to
measure the DM loss through any CMC. It is also useful for measuring other
two-terminal transmissive devices such as filters, attenuators, active
stages, and.......
Have a look at my first cut. I'd invite anyone to make suggestions to make
things clearer and/or correct any errors I've made in the write-up. Have a
read of the attachment.
The next installment will address measuring the bulk CM impedance presented
by the CMCs using the NANOs and SAVER (another day, please) which have been
previously measured using the HP equipment.
Dave - W?LEV
-- *Dave - W?LEV* *Just Let Darwin Work*
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So why use them as a comparison with multiple variables?? ?NO THE SETUPS need to be the same to be a real comparison.? Do your home work.
Mel, K6KBE
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On Friday, January 29, 2021, 04:24:59 PM PST, David Eckhardt <davearea51a@...> wrote: Setups HAD to change.? The initial measurements were made with the HP 8753C.? Those I put out today with the procedure are made using the NANOVNA and SAVER.? Of course the setups are DIFFERENT!!!!!!? ENTIRELY DIFFERENT INSTRUMENTS!!!!!! Dave - W?LEV On Fri, Jan 29, 2021 at 11:02 PM Mel Farrer via groups.io <farrerfolks= [email protected]> wrote: ? David, thanks for the good work, but I have one question,
1.? With all of the equipment and access to the testing site, did you make
the measurements at different times and different calibrations?? Sort of
defeats the accuracy right off the get go.? In my book any serious
engineering comparisons like that, are done at one sitting, N O changes in
setup PERIOD.? Sorry, my stick.
Mel, K6KBE
? ? On Friday, January 29, 2021, 02:25:24 PM PST, David Eckhardt <
davearea51a@...> wrote:
? With all my recent measurements of CMCs, I've been encouraged by several
readers to put together a procedure for the various measurements I've made
with the HP 8753C, but using the NANOVNAs and SAVER.? The attachment is the
first installment which presents a procedure using the NANOs and SAVER to
measure the DM loss through any CMC.? It is also useful for measuring other
two-terminal transmissive devices such as filters, attenuators, active
stages, and.......
Have a look at my first cut.? I'd invite anyone to make suggestions to make
things clearer and/or correct any errors I've made in the write-up.? Have a
read of the attachment.
The next installment will address measuring the bulk CM impedance presented
by the CMCs using the NANOs and SAVER (another day, please) which have been
previously measured using the HP equipment.
Dave - W?LEV
-- *Dave - W?LEV* *Just Let Darwin Work*
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OK. you clearly do not understand. I quit....... Dave - W?LEV On Sat, Jan 30, 2021 at 1:40 AM Mel Farrer via groups.io <farrerfolks= [email protected]> wrote: So why use them as a comparison with multiple variables? NO THE SETUPS
need to be the same to be a real comparison. Do your home work.
Mel, K6KBE
On Friday, January 29, 2021, 04:24:59 PM PST, David Eckhardt <
davearea51a@...> wrote:
Setups HAD to change. The initial measurements were made with the HP
8753C. Those I put out today with the procedure are made using the NANOVNA
and SAVER. Of course the setups are DIFFERENT!!!!!! ENTIRELY DIFFERENT
INSTRUMENTS!!!!!!
Dave - W?LEV
On Fri, Jan 29, 2021 at 11:02 PM Mel Farrer via groups.io <farrerfolks=
[email protected]> wrote:
David, thanks for the good work, but I have one question,
1. With all of the equipment and access to the testing site, did you make
the measurements at different times and different calibrations? Sort of
defeats the accuracy right off the get go. In my book any serious
engineering comparisons like that, are done at one sitting, N O changes in
setup PERIOD. Sorry, my stick.
Mel, K6KBE
On Friday, January 29, 2021, 02:25:24 PM PST, David Eckhardt <
davearea51a@...> wrote:
With all my recent measurements of CMCs, I've been encouraged by several
readers to put together a procedure for the various measurements I've made
with the HP 8753C, but using the NANOVNAs and SAVER. The attachment is the
first installment which presents a procedure using the NANOs and SAVER to
measure the DM loss through any CMC. It is also useful for measuring other
two-terminal transmissive devices such as filters, attenuators, active
stages, and.......
Have a look at my first cut. I'd invite anyone to make suggestions to make
things clearer and/or correct any errors I've made in the write-up. Have a
read of the attachment.
The next installment will address measuring the bulk CM impedance presented
by the CMCs using the NANOs and SAVER (another day, please) which have been
previously measured using the HP equipment.
Dave - W?LEV
--
*Dave - W?LEV*
*Just Let Darwin Work*
-- *Dave - W?LEV* *Just Let Darwin Work*
|
Don't yield to unreasonable people, that's what they want.
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On Sat, 30 Jan 2021 at 02:43, David Eckhardt <davearea51a@...> wrote: OK. you clearly do not understand. I quit.......
Dave - W?LEV
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Thank you for sharing.
Looking forward to seeing your process for measuring common mode attenuation through a CMC :-)
--
VE6WGM
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On Fri, Jan 29, 2021 at 03:02 PM, Mel Farrer wrote: In my book any serious engineering comparisons like that, are done at one
sitting, N O changes in setup PERIOD. Yes, in an ideal world, all tests would be done with no changes in the setup. Unfortunately, we - at least most of us - don't live in an ideal world, we live in the real world. A number of NanoVNA users have compared their Nanos to HP equipment and have found that the Nanos, while by no means equivalent to HP equipment, are pretty darn good. If we needed to know to a fraction of an ohm the common mode impedance of a particular choke, we'd be out of luck. But most of us don't need that kind of accuracy, and the NanoVNAs suit us just fine. ¡°It is the mark of an instructed mind to rest satisfied with that degree of precision which the nature of the subject admits, and not to seek exactness where only an approximation of the truth is possible.¡± - Aristotle
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Nice write-up of your method.
Only a comment on the measurement outcome itself.
In the Smith Chart it becomes clear that the transmissionline impedance (the sort of twinlead windings on the core) is about 85 ohms that introduces the varying SWR in the S21 measurement.
Ofcourse, this can be overcome.
At 500 kHz (also on the Smith Chart) I expected the trace to start closer to 50 ohm.
73,
Arie PA3A
Op 29-1-2021 om 23:24 schreef David Eckhardt:
toggle quoted message
Show quoted text
With all my recent measurements of CMCs, I've been encouraged by several
readers to put together a procedure for the various measurements I've made
with the HP 8753C, but using the NANOVNAs and SAVER. The attachment is the
first installment which presents a procedure using the NANOs and SAVER to
measure the DM loss through any CMC. It is also useful for measuring other
two-terminal transmissive devices such as filters, attenuators, active
stages, and.......
Have a look at my first cut. I'd invite anyone to make suggestions to make
things clearer and/or correct any errors I've made in the write-up. Have a
read of the attachment.
The next installment will address measuring the bulk CM impedance presented
by the CMCs using the NANOs and SAVER (another day, please) which have been
previously measured using the HP equipment.
Dave - W?LEV
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Gregg Messenger VE6WGM
Jim Allyn - N7JA
Arie Kleingeld PA3A