Re: USING THE NANOVNA AND SAVER TO MEASURE CM ATTENUATION THROUGH CMCs
On Tuesday 02 February 2021 01:17:23 pm David Eckhardt wrote: oooops. When I send them to the files section, I shall do so. Thanks
for the suggestion. I thought Apple could read .docx files. Are we back
to Apple vs. IBM? Humbug...... I've run nothing but linux here since 1999... -- 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: USING THE NANOVNA AND SAVER TO MEASURE CM ATTENUATION THROUGH CMCs
On Tuesday 02 February 2021 01:14:53 pm Joe St. Clair AF5MH wrote: I suggest that you convert the document to PDF format. The .docx format seems to be problematic on non-Microsoft systems. Agreed. I _can_ open those docx files, but won't for the most part bother... -- 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: USING THE NANOVNA AND SAVER TO MEASURE CM ATTENUATION THROUGH CMCs
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On Wednesday, February 3, 2021, 10:41:04 a.m. EST, Manfred Mornhinweg <manfred@...> wrote:
I was also opening these docx files in OpenOffice, on my good old Windows XP. But like Jean-Denis comments, the format gets screwed up, the colums don't align.
Using PDF is much better. Probably pretty much any computer and similar device in the world has a PDF reader installed, that works well. And most text processors can write PDF files directly, and for those that cannot, it's easy enough to print to a PDF conversion utility. So their is no good reason to distribute text files in the internal formats of specific text processor programs.
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Re: USING THE NANOVNA AND SAVER TO MEASURE CM ATTENUATION THROUGH CMCs
I was also opening these docx files in OpenOffice, on my good old Windows XP. But like Jean-Denis comments, the format gets screwed up, the colums don't align.
Using PDF is much better. Probably pretty much any computer and similar device in the world has a PDF reader installed, that works well. And most text processors can write PDF files directly, and for those that cannot, it's easy enough to print to a PDF conversion utility. So their is no good reason to distribute text files in the internal formats of specific text processor programs.
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From what I understand SAA2N has better dynamic range than the 1.5GHz nanoVNA and thus is better for duplexer and cavity filter tuning.
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Re: NanoVNA RF Demo Kit connection
Regarding the two 3D-printed tools I posted, use 0.15 mm (or 0.2 mm) layer height,
and 100 % infill when slicing for 3D-print.
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Re: NanoVNA RF Demo Kit connection
I had the same problem with the U.FL connectors .
I modelled a small tool to solve the problem, thinking it should be used to connect, and then removed.
When I had made a test printout, I realized that it could be left on the U.FL connector. It will stick to the
connector and cable.
I have also made a small 8 mm wrench for SMA-connectors, I guess it will break before the connector is
tightened too much.
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I have posted on this before a month or so ago.
You will need a very thin nut, otherwise the control buttons will disappear. Also those nuts are vey difficult to find and I would probably cut up the sleeve of an old N connector if I were going to do it. I have a lathe which would make the job easier.
If you take the 2N innards out of the metal case, you will see that the top plate actually rests on some lugs inside the case. If the assembly is put together right, the nuts on the N connectors actually tighten the top plate against these lugs, not against the edge of the circuit board, which is in effect, floating.
I have not actually seen a single post about the connectors actually coming loose off the 2N board. I think it may be because people incorrectly occasionally use a ¡°wrench¡± on sma connectors, but only use bare fingers on N connectors as there is only knurling for a gentle finger grip, rather than flats on which a spanner might rest. (I suppose Mr Low-iq Armstrong might try a mole wrench, but is probably too thick to know what a network is).
I always push the N or sma connector home first, before tightening the ring, rather than use the ring to draw the connectors together.
Steve L
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Re: USING THE NANOVNA AND SAVER TO MEASURE CM ATTENUATION THROUGH CMCs
Hi Jean-Denis
I'm not in thrall to paid for uSoft stuff. docx opens fine with 'open office' on my win7 pc, but I agree, docx is not the best for universal use.
On the group I run we try to upload files as .txt or .doc [office 97] - and for the last, a pdf as well.
73
John
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Re: USING THE NANOVNA AND SAVER TO MEASURE CM ATTENUATION THROUGH CMCs
Hi Dave
Thank you for your really helpful reply. Puts a lot into perspective.
My comment on wire was not directed to metric/imperial - that's a minor inconvenience, just means using wire tables- but to proprietry wire types, eg "'antenna' wire from DavisRF ".
I looked at the Davis RF site - there are several possibilities- did you use flexweave, pe or pvc insulation?
73
John G8JMB
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Re: [Amateur-repairs] USING THE NANOVNA AND SAVER TO MEASURE CM ATTENUATION THROUGH CMCs
Hi Dave,
good work, but some pics can't be displayed over here. Do you think you can provide this document as PDF please?
Thank you.
Carsten, DL8AAP
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David Eckhardt < davearea51a@... > hat am 01.02.2021 23:00
geschrieben:
I promised this, so here it is. See the attachment for a procedure to
measure the CM attenuation through CMCs and other 4-terminal devices (as
in
s-parameters). Comments and improvements are welcome before I post it to
the files section.
Dave - W?LEV
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Re: USING THE NANOVNA AND SAVER TO MEASURE CM ATTENUATION THROUGH CMCs
.docx works just fine on Mac OS, but you need MS Word. Not quite. You don¡¯t need MS Word to read .docx documents on Mac OS. There are a few other ways: - Apple¡¯s word processor, Pages, can open them too - Even TextEdit, the basic text editor included with MacOS, can open them In both cases, there are many cases of the layout being screwed up. One common case is if the document uses a font that is not available on the Mac. In general .docx is not a wise choice to distribute a document flawlessly. Jean-Denis On Feb 2, 2021, at 12:18, Jim Lux <jim@...> wrote:
.docx works just fine on Mac OS, but you need MS Word.
Dave
On Tue, Feb 2, 2021 at 6:15 PM Joe St. Clair AF5MH <saintc@...>
wrote:
I suggest that you convert the document to PDF format. The .docx format
seems to be problematic on non-Microsoft systems.
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Thanks, Zack! Very interesting. I shall have to listen for them. Thank
you!
Dave
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On Wed, Feb 3, 2021 at 1:00 AM Zack Widup <w9sz.zack@...> wrote: The 13 MHz beacons are legal under Part 15. They only run a couple
milliwatts.
W1TAG has calculated that the beacons with a couple milliwatts meet the
regulations:
www.w1tag.com/Hifer2.pdf
The FCC has known about them for many years. Never - not once - have they
attempted to shut one down. I am always amazed that we can have propagation
that allows me to hear them in the Midwest!
A squarer is an FSK CW signal with typically a 4 or 5 Hz shift. Many are
QRSS, commonly with a 6-second "dit" and an 18-second "dah." They are
copyable by looking at your radio's audio with a computer sound card with a
program such as Spectrum Monitor, and a frequency range of maybe 20 to 50
Hz. You can visually copy the CW that way. The term "squarer" is in common
use by those of us who copy these beacons.
There are occasionally a couple QRSS squarers at the very bottom of the 40
meter band. The ones I've heard are on 7000.400 and 7000.700 kHz. With a
4-second FSK and a QRSS with the 6-second dit, bandwidth is so narrow that
there is no chance of them being out of the band. The ops only activate
them when they can be there as control operators, so operation is random
and unpredictable. They will QSL reception. I have their QSL's. To the
untrained ear, they sound like carriers. But to those who have been
listening to QRSS squarers, we recognize they aren't just carriers and set
up to decode them.
You learn something new every day, eh? I'm surprised that there aren't more
hams interested in what goes on outside the ham bands on shortwave.
Zack W9SZ
On Tue, Feb 2, 2021 at 3:47 PM David Eckhardt <davearea51a@...>
wrote:
What the dickens are "Squarers"? I'll confess the ISM bands are a good
place to hide possibly illegal and unlicensed emissions. However, as a
licensed ham for some 61 years and worked professionally in the EMC
regulatory world for some 35 years, I can not condone the practice.
Dave - W?LEV
On Tue, Feb 2, 2021 at 9:19 PM Zack Widup <w9sz.zack@...> wrote:
Probably has nothing to do with his use, but 13.56 MHz and surrounding
frequencies on shortwave are the homes of many unlicensed CW beacons. Many
are "squarers."
Zack W9SZ
On Tue, Feb 2, 2021 at 8:52 AM Jim Lux <jim@...> wrote:
On 2/2/21 5:04 AM, brown.beard.2020@... wrote:
Hi All
Sorry if this is not the right place to ask. Feel free to point me to a
more suitable place for my questions.
I have an antenna connected to a 13.56MHz RF signal and would like
to
add a ferrite core to the cable from the antenna to the device to
filter
out any noise coming from the environment.
How do i determine the appropriate specs for the ferrite core?
That's the ISM frequencies just below the amateur radio 20 meter
band,
so anything that works for 14 MHz (20m) will probably work just fine
for
13.56 MHz.
In general, 31 mix is a good choice for HF - it's suitably lossy at
those frequencies. You might check out K9YC's choke cookbooks and
other
writeups..
You're presumably at low power for something like a badge reader, so
you
probably aren't as interested in low loss transmitter designs.
*RFI, Ferrites, and Common Mode Chokes For Hams
<>**Most recent update
April
2019.*This tutorial is directed specifically to RFI in ham radio
applications. It includes an extended discussion of the use of common
mode chokes in antenna systems and for suppression of RFI. A chapter
on
audio and computer interconnections in ham stations shows how to make
bulletproof connections between a computer sound card and ham rigs
for
SSB, RTTY, PSK31, and SO2R contesting without expensive interface
boxes,
using nothing more than simple cables with the right connectors on
each
end. There's also a chapter on grounding and bonding.
This is a new applications note summarizing my work on *Chokes and
Transformers For Receiving Antennas.
<
**NEW!*October
2018
<
Virus-free.
www.avg.com
<
<#DAB4FAD8-2DD7-40BB-A1B8-4E2AA1F9FDF2>
--
*Dave - W?LEV*
*Just Let Darwin Work*
--
*Dave - W?LEV*
*Just Let Darwin Work*
|
The 13 MHz beacons are legal under Part 15. They only run a couple
milliwatts.
W1TAG has calculated that the beacons with a couple milliwatts meet the
regulations:
www.w1tag.com/Hifer2.pdf
The FCC has known about them for many years. Never - not once - have they
attempted to shut one down. I am always amazed that we can have propagation
that allows me to hear them in the Midwest!
A squarer is an FSK CW signal with typically a 4 or 5 Hz shift. Many are
QRSS, commonly with a 6-second "dit" and an 18-second "dah." They are
copyable by looking at your radio's audio with a computer sound card with a
program such as Spectrum Monitor, and a frequency range of maybe 20 to 50
Hz. You can visually copy the CW that way. The term "squarer" is in common
use by those of us who copy these beacons.
There are occasionally a couple QRSS squarers at the very bottom of the 40
meter band. The ones I've heard are on 7000.400 and 7000.700 kHz. With a
4-second FSK and a QRSS with the 6-second dit, bandwidth is so narrow that
there is no chance of them being out of the band. The ops only activate
them when they can be there as control operators, so operation is random
and unpredictable. They will QSL reception. I have their QSL's. To the
untrained ear, they sound like carriers. But to those who have been
listening to QRSS squarers, we recognize they aren't just carriers and set
up to decode them.
You learn something new every day, eh? I'm surprised that there aren't more
hams interested in what goes on outside the ham bands on shortwave.
Zack W9SZ
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Show quoted text
On Tue, Feb 2, 2021 at 3:47 PM David Eckhardt <davearea51a@...> wrote: What the dickens are "Squarers"? I'll confess the ISM bands are a good
place to hide possibly illegal and unlicensed emissions. However, as a
licensed ham for some 61 years and worked professionally in the EMC
regulatory world for some 35 years, I can not condone the practice.
Dave - W?LEV
On Tue, Feb 2, 2021 at 9:19 PM Zack Widup <w9sz.zack@...> wrote:
Probably has nothing to do with his use, but 13.56 MHz and surrounding
frequencies on shortwave are the homes of many unlicensed CW beacons. Many
are "squarers."
Zack W9SZ
On Tue, Feb 2, 2021 at 8:52 AM Jim Lux <jim@...> wrote:
On 2/2/21 5:04 AM, brown.beard.2020@... wrote:
Hi All
Sorry if this is not the right place to ask. Feel free to point me to a
more suitable place for my questions.
I have an antenna connected to a 13.56MHz RF signal and would like to
add a ferrite core to the cable from the antenna to the device to
filter
out any noise coming from the environment.
How do i determine the appropriate specs for the ferrite core?
That's the ISM frequencies just below the amateur radio 20 meter band,
so anything that works for 14 MHz (20m) will probably work just fine
for
13.56 MHz.
In general, 31 mix is a good choice for HF - it's suitably lossy at
those frequencies. You might check out K9YC's choke cookbooks and
other
writeups..
You're presumably at low power for something like a badge reader, so
you
probably aren't as interested in low loss transmitter designs.
*RFI, Ferrites, and Common Mode Chokes For Hams
<>**Most recent update
April
2019.*This tutorial is directed specifically to RFI in ham radio
applications. It includes an extended discussion of the use of common
mode chokes in antenna systems and for suppression of RFI. A chapter on
audio and computer interconnections in ham stations shows how to make
bulletproof connections between a computer sound card and ham rigs for
SSB, RTTY, PSK31, and SO2R contesting without expensive interface
boxes,
using nothing more than simple cables with the right connectors on each
end. There's also a chapter on grounding and bonding.
This is a new applications note summarizing my work on *Chokes and
Transformers For Receiving Antennas.
<
**NEW!*October
2018
<
Virus-free.
www.avg.com
<
<#DAB4FAD8-2DD7-40BB-A1B8-4E2AA1F9FDF2>
--
*Dave - W?LEV*
*Just Let Darwin Work*
|
On Tue, Feb 2, 2021 at 01:10 PM, David Eckhardt wrote: There are 7 frequencies allocated by the FCC for that purpose in that specific
ISM band - in a NON_RADIATIVE MANNER. Not so: ¡ì18.305 Field strength limits. (a) ISM equipment operating on a frequency specified in ¡ì18.301 is permitted **unlimited radiated energy** in the band specified for that frequency. (Emphasis mine.) However: (b) The field strength levels of **emissions which lie outside the bands** specified in ¡ì18.301, unless otherwise indicated, shall not exceed the following: ... (Emphasis mine.)
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Re: backyard antenna ranges
I'm having lots of trouble with my local area coverage. Neither my
multiband HF vertical (a CHA-250B with its base mounted about 14ft above
ground) nor my G5RV dipole in roughly NVIS mount with 100w can be heard on
10m or 40m by friends about 2-6 miles away. My main interest is about a
500-1000 mi radius around my QTH. Now trying a KISS-SSB counterpoise and
also my ATAS-120a autotune stick that goes with my FT-991a. VHF isn't a
problem. Any suggestions?
Chuck
K4TZO
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On Tue, Feb 2, 2021 at 5:40 PM Jim Lux <jim@...> wrote: I'd like to start a discussion about using the NanoVNA (or NanoVNA2) in
the context of a backyard antenna range. One of the tricky things about
doing antenna measurements has always been the whole "calibration"
thing, or the need to remote control a source (or receiver).
Hey, the NanoVNA does half that work for you! It's in the back yard, so
it's probably not going to be doing very much for your 160meter full
size yagi, but for VHF and UHF, or for "near field" systems with small
loop antennas, it should work quite nicely. If you wanted to evaluate
the antenna on a walkie talkie, it would be great.
The current crop of VNAs doesn't do WiFi bands, but I think it's useful
to think about it. (these days, running patterns of 2.45 GHz antennas
is a standard thing in undergrad antenna classes - but they get to use
the fancy Keysight box, provided at attractive prices to universities)
What I'm thinking is using a deliberately non-matched "probe", the
radiation pattern of which you can determine by modeling. Or build 3
and do a three cornered hat measurement. It could be as simple as a
(very) short dipole with a good choke.
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Yes, RFID uses the 13.56 MHz ISM band (yes, I've worked professionally
there, as well....), but energy is closely coupled only inductively - NOT
in a radiative manner. Some 'uninitiated' engineers call the usually
pringed inductor an antenna, which it certainly is not.
Dave - W?LEV
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On Tue, Feb 2, 2021 at 9:28 PM Jim Lux <jim@...> wrote: On 2/2/21 1:10 PM, David Eckhardt wrote:
13.56 MHz is an ISM (Industrial, Scientific, and Medical) frequency. There
are 7 frequencies allocated by the FCC for that purpose in that specific
ISM band - in a NON_RADIATIVE MANNER. Why are you connecting an antenna to
a 13.56 MHz source? RFID uses 13.56 MHz with radiated fields (limited, it's true), but all
those "near field communications" things are also 13.56 (Subway cards,
cashless payments, etc.).
If you're making a "long range" reader (e.g. for a doorway portal
application) you wind up with directive arrays of some sort, but you
also run into problems with RFI.
Most of the MetCal soldering stations operate on 13.56 MHz.
Dave - W?LEV
On Tue, Feb 2, 2021 at 8:57 PM Jim Allyn - N7JA <
jim@...>
wrote:
On Tue, Feb 2, 2021 at 05:54 AM, <brown.beard.2020@...> wrote:
I have an antenna connected to a 13.56MHz RF signal and would like to add a
ferrite core to the cable from the antenna to the device to filter out any
noise coming from the environment. It isn't clear to me what the situation is here. Do you mean you have an
antenna connected to a 13.56 MHz signal coming from a signal generator
or
transmitter of some sort, and you wish to transmit that13.56 MHz signal?
Or, you have an antenna you are using to receive a 13.56 MHz signal, and
you would like to prevent interference picked up by the transmission
line
from being brought into the shack? Or you have something else (NOT
13.56
MHz) you are trying to receive and the 13.56 MHz signal is interfering
with
it? Please clarify.
--
*Dave - W?LEV*
*Just Let Darwin Work*
|
Re: backyard antenna ranges
Jim, I've usually used a capacitive probe for the purpose at home. That
means a very short probe above an image plane or a very short dipole as a
function of the wavelength of the highest frequency desired. It works well
as a pretty much frequency insensitive receiving antenna.
And, I believe the latest version of the NANO V2's end at 6 GHz.
You have hit a need directly on the head. If you don't, I will - given a
little time to decompress from my CMC ventures....
There are available PC printed LPDA's available with published antenna
factors that cover up to 3 GHz for less t6han $15. i have two. These are
about as good for the amateur as the expensive LPDAs used professionally in
accredited labs.
DO IT for the good of the NANO bunch!!!!
With encouragement:
Dave - W?LEV
Dave - W?LEV
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On Tue, Feb 2, 2021 at 10:40 PM Jim Lux <jim@...> wrote: I'd like to start a discussion about using the NanoVNA (or NanoVNA2) in
the context of a backyard antenna range. One of the tricky things about
doing antenna measurements has always been the whole "calibration"
thing, or the need to remote control a source (or receiver).
Hey, the NanoVNA does half that work for you! It's in the back yard, so
it's probably not going to be doing very much for your 160meter full
size yagi, but for VHF and UHF, or for "near field" systems with small
loop antennas, it should work quite nicely. If you wanted to evaluate
the antenna on a walkie talkie, it would be great.
The current crop of VNAs doesn't do WiFi bands, but I think it's useful
to think about it. (these days, running patterns of 2.45 GHz antennas
is a standard thing in undergrad antenna classes - but they get to use
the fancy Keysight box, provided at attractive prices to universities)
What I'm thinking is using a deliberately non-matched "probe", the
radiation pattern of which you can determine by modeling. Or build 3
and do a three cornered hat measurement. It could be as simple as a
(very) short dipole with a good choke.
--
*Dave - W?LEV*
*Just Let Darwin Work*
|
Re: USING THE NANOVNA AND SAVER TO MEASURE CM ATTENUATION THROUGH CMCs
On Tue, Feb 2, 2021 at 02:34 PM, Dragan Milivojevic wrote:
Hardware capability? What are you referring to?
In order to do the S21 series method of determine complex impedance you need the Port 1 (CH0) and Port 2 (CH1) impedance to be very close to 50 ohms. You also need to be able to do 10/12 point error correction which the nanoVNA cannot do. Both are necessary in order to get an accurate S21 phase measurement. VNA's like Agilent etc can do the measurement because they are bidirectional. Kurt Poulsen described the issue in this post... /g/nanovna-users/message/13075?p=,,,20,0,0,0::Created,,s21+series+method,20,2,0,73384240 I have tried using attenuators on CH0 and CH1 to overcome the 50 ohm issue but the phase was still off even though I carefully constructed test jigs to minimize parasitic capacitance. You can easily see the problem if you make a test jig that measures a 1000 ohm SMD resistor which has minimal reactance at HF frequencies. The S21 magnitude will be accurate but the S21 phase will not be 0 so when you do the calculations you get a reactance that is not there... Roger
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I'd like to start a discussion about using the NanoVNA (or NanoVNA2) in the context of a backyard antenna range.? One of the tricky things about doing antenna measurements has always been the whole "calibration" thing, or the need to remote control a source (or receiver).
Hey, the NanoVNA does half that work for you!? It's in the back yard, so it's probably not going to be doing very much for your 160meter full size yagi, but for VHF and UHF, or for "near field" systems with small loop antennas, it should work quite nicely.? If you wanted to evaluate the antenna on a walkie talkie, it would be great.
The current crop of VNAs doesn't do WiFi bands, but I think it's useful to think about it.? (these days, running patterns of 2.45 GHz antennas is a standard thing in undergrad antenna classes - but they get to use the fancy Keysight box, provided at attractive prices to universities)
What I'm thinking is using a deliberately non-matched "probe", the radiation pattern of which you can determine? by modeling.? Or build 3 and do a three cornered hat measurement.? It could be as simple as a (very) short dipole with a good choke.
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Ismo V??n?nen OH2FTG
DL8AAP Carsten
Jim Allyn - N7JA
Chuck Cole
Roger Need