Someone gave me a large chunk of 7/8" Heliax to test for him.
It is in pretty bad shape for sure.
I want to do two things, can anyone explain how to do the following?
1- Verify that it is indeed 50 Ohms.
2- Measure it's loss
Can it measure the defects? I has several pretty bad dents (Impedance bump?)
And one spot where it looks like it was even twisted 90 degrees!
Joe WB9SBD
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Re: NanoVNA-App v1.1.209 output file format
Stan,
No apology needed.? Thanks for the info.? I've done some spreadsheet work on the data already, and they look reasonable.
Thanks and 73, Jay
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On 11/10/2023 11:45 AM, Stan Dye wrote: Sorry for not making it clear in my reply, Jay.
The .csv files have the identical data as the .s2p files. They are the same columns in the same order, but delimited by commas rather than spaces.
This makes the data easier to load into a spreadsheet to do your own calculations. Several users in this group have shared spreadsheets that do specialized calculations. I don't personally use any of them, but if you search the messages for 'excel' or 'spreadsheet', you can find them.
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Re: NanoVNA-App v1.1.209 output file format
Sorry for not making it clear in my reply, Jay.
The .csv files have the identical data as the .s2p files. They are the same columns in the same order, but delimited by commas rather than spaces.
This makes the data easier to load into a spreadsheet to do your own calculations. Several users in this group have shared spreadsheets that do specialized calculations. I don't personally use any of them, but if you search the messages for 'excel' or 'spreadsheet', you can find them.
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Re: NanoVNA-App v1.1.209 output file format
Stan,
Thanks. I'm very familiar with the Touchstone files, but the .csv has no
column headers or comments, so I don't know which parameters are there nor
what format (real and imaginary, mag and phase, etc.).
Thanks.
Jay
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On Thu, Nov 9, 2023, 11:11 AM Stan Dye <standye@...> wrote: The .s1p and .s2p files are touchstone files. An excellent description is
here:
What is a Touchstone file? - Kirkby Microwave
On Thu, Nov 9, 2023, 8:48 AM Jay Diepenbrock KM4EP <jdiepenb@...>
wrote:
Please point me to something that describes the output format of the .s2p
and .csv files exported by the app.
Thanks.
Jay KM4EP
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Re: An affordable female calibration kit, anywhere?
Me too. By the way, for the future, how can you tell when a connector has worn out too much.
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Re: Data Outside The Smith Chart (?)
On Wednesday 08 November 2023 05:24:39 pm Richard Jamsek wrote: File won't download. Flaged as corrupted.
Richard K8CYK Opens just fine here... On Wed, Nov 8, 2023, 11:30 AM Allen Hill via groups.io <Allenanalog1=
[email protected]> wrote:
Hi guys, just happened upon this thread. Not sure if its applicable, but
if you're measuring a scope probe it maybe more complex than you think (10x
probe). See the attached patent on the scope probe. The cable from the tip
to the instrument (scope) is actually a distributed resistor. If you have a
cheap (or bad one) available you should tear it apart. Quite interesting.
Allen Hill
KI4QCK -- Member of the toughest, meanest, deadliest, most unrelenting -- and ablest -- form of life in this section of space, ?a critter that can be killed but can't be tamed. ?--Robert A. Heinlein, "The Puppet Masters" - Information is more dangerous than cannon to a society ruled by lies. --James M Dakin
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Re: NanoVNA-App v1.1.209 output file format
The .s1p and .s2p files are touchstone files. An excellent description is here: What is a Touchstone file? - Kirkby Microwave On Thu, Nov 9, 2023, 8:48 AM Jay Diepenbrock KM4EP <jdiepenb@...> wrote: Please point me to something that describes the output format of the .s2p
and .csv files exported by the app.
Thanks.
Jay KM4EP
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NanoVNA-App v1.1.209 output file format
Please point me to something that describes the output format of the .s2p and .csv files exported by the app.
Thanks.
Jay KM4EP
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Re: An affordable female calibration kit, anywhere?
BTW, I also use an SMA M-F adapter on the connectors on the NanoVNA because of the limited lifespan of the connectors. They are more or less permanently attached and everything goes through them. If they wear out, I¡¯ll replace ¡®em, no soldering needed. I¡¯ll be getting them for my tinySA too.
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Re: Data Outside The Smith Chart (?)
Thanks for that Allen, very interesting.
Cheers...Bob VK2ZRE
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On 9/11/2023 5:29 am, Allen Hill via groups.io wrote: Hi guys, just happened upon this thread. Not sure if its applicable, but if you're measuring a scope probe it maybe more complex than you think (10x probe). See the attached patent on the scope probe. The cable from the tip to the instrument (scope) is actually a distributed resistor. If you have a cheap (or bad one) available you should tear it apart. Quite interesting.
Allen Hill
KI4QCK
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Re: An affordable female calibration kit, anywhere?
Another resource that I found to have fantastic information on building calibration kits: There's a followup video where he goes through and tweaks the "open" to further optimize. On Wed, Nov 8, 2023 at 6:05?PM Russell C. Nixon <rcnixon@...> wrote: Get a crimper and some connectors and make your own M/F cables. The coax
used is either RG-316 or RG-174. The RG-316 is preferred as it is low-loss
although I doubt it makes a difference at 150 mm. Oh yeah, some
amalgamating heat shrink tubing will be handy for strain relief. The
amalgamating tubing has a heat-activated coating of glue on the inside.
Ten male SMA crimp connectors are less than $10 US, same for the female
SMAs and the RG-316 is $15 US.
For 35 bucks, you'll have 10 M-F jumpers in your choice of lengths.
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Re: An affordable female calibration kit, anywhere?
Get a crimper and some connectors and make your own M/F cables. The coax used is either RG-316 or RG-174. The RG-316 is preferred as it is low-loss although I doubt it makes a difference at 150 mm. Oh yeah, some amalgamating heat shrink tubing will be handy for strain relief. The amalgamating tubing has a heat-activated coating of glue on the inside.
Ten male SMA crimp connectors are less than $10 US, same for the female SMAs and the RG-316 is $15 US.
For 35 bucks, you'll have 10 M-F jumpers in your choice of lengths.
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Thank you to you and Fran?ois for the dive into Zo.
I'm always ready to listen and learn.
Russ
kf4wxd
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Thank you, that's the ticket! I couldn't remember it despite looking right at the "Display" menu item.
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Re: Data Outside The Smith Chart (?)
If that doesn't work, its Tektronix US Patent 2883619. Should be easy to find online.
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On November 8, 2023, at 6:09 PM, "Allen Hill via groups.io" <allenanalog1@...> wrote: Try this one. On Nov 8, 2023, at 5:24 PM, Richard Jamsek <K8cyk56@...> wrote:
?File won't download. Flaged as corrupted.
Richard K8CYK
On Wed, Nov 8, 2023, 11:30 AM Allen Hill via groups.io <Allenanalog1=
[email protected]> wrote:
Hi guys, just happened upon this thread. Not sure if its applicable, but
if you're measuring a scope probe it maybe more complex than you think (10x
probe). See the attached patent on the scope probe. The cable from the tip
to the instrument (scope) is actually a distributed resistor. If you have a
cheap (or bad one) available you should tear it apart. Quite interesting.
Allen Hill
KI4QCK
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Re: Data Outside The Smith Chart (?)
Try this one.
toggle quoted message
Show quoted text
On Nov 8, 2023, at 5:24 PM, Richard Jamsek <K8cyk56@...> wrote:
?File won't download. Flaged as corrupted.
Richard K8CYK
On Wed, Nov 8, 2023, 11:30 AM Allen Hill via groups.io <Allenanalog1=
[email protected]> wrote:
Hi guys, just happened upon this thread. Not sure if its applicable, but
if you're measuring a scope probe it maybe more complex than you think (10x
probe). See the attached patent on the scope probe. The cable from the tip
to the instrument (scope) is actually a distributed resistor. If you have a
cheap (or bad one) available you should tear it apart. Quite interesting.
Allen Hill
KI4QCK
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Re: Data Outside The Smith Chart (?)
File won't download. Flaged as corrupted. Richard K8CYK On Wed, Nov 8, 2023, 11:30 AM Allen Hill via groups.io <Allenanalog1= [email protected]> wrote: Hi guys, just happened upon this thread. Not sure if its applicable, but
if you're measuring a scope probe it maybe more complex than you think (10x
probe). See the attached patent on the scope probe. The cable from the tip
to the instrument (scope) is actually a distributed resistor. If you have a
cheap (or bad one) available you should tear it apart. Quite interesting.
Allen Hill
KI4QCK
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Where you can measure the input impedance of a cable pair, a good way to determine Zo is:
Zo = SQRT(Zoc * Zsc)
where Zoc is measured with the distant end open circuited and Zsc is measured with the distant end short circuited. Note that Zoc and Zsc are complex values when the attenuation of the line is not negligible and are functions of frequency so they need to be measured accurately.
73,
Maynard
W6PAP
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On 11/7/23 13:48, W0LEV wrote: 1) Be sure your coax is less than 1/4-wavelength long in the coax
(considering Vp). Conversely, be sure your measurement frequency of
measurement is less than the electrical length of the cable.
2) Open terminate the far end of the cable.
3) On the Smith chart more-or-less in the center of the locus, note the
capacitance.
4) Short terminate the far end of the cable.
Do not change frequency or move your measurement frequency.
5) On the Smith Chart note the inductance.
6) Calculate the impedance using:
Zo = SQRT [ L / C ]
Dave - W?LEV
On Tue, Nov 7, 2023 at 8:58?PM Russell C. Nixon <rcnixon@...>
wrote:
Can someone point me to a reference in the Wiki for screen scaling? I¡¯m
trying w1aew¡¯s method for determining the characteristic impedance of an
unknown piece of coax as an exercise. I¡¯m getting close but the Smith chart
trace is a tight little knot in the center. W1aew¡¯s video shows a nice
¡°ram¡¯s horn¡± trace on the Smith chart. I think the scaling will be useful
in other areas too. Thanks in advance.
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Re: Data Outside The Smith Chart (?)
Hi guys, just happened upon this thread. Not sure if its applicable, but if you're measuring a scope probe it maybe more complex than you think (10x probe). See the attached patent on the scope probe. The cable from the tip to the instrument (scope) is actually a distributed resistor. If you have a cheap (or bad one) available you should tear it apart. Quite interesting.
Allen Hill
KI4QCK
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We had discussed at length the measurement of characteristic impedance. See this production /g/nanovna-users/message/32568Which shows how, with a nanoVNA, to calculate the characteristic impedance of a cable as a function of frequency With Excel, it is easy to manipulate complex numbers. Here we take the square root of the product. -- F1AMM Fran?ois
-----Message d'origine----- De la part de Maynard Wright, P. E., W6PAP Envoy¨¦ : mercredi 8 novembre 2023 16:40
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Jay KM4EP