Re: Interesting phenomenon
Zack W9SZ wrote:
I thought I'd send this e-mail as a curiosity of something I discovered. If
you're trying to measure something with the NanoVNA and there is a strong
transmitted signal source nearby close to the frequency you're trying to
measure at, it could affect your readings
Here's a way to avoid the problem at least sometimes.
I've had something similar happen and since I was measuring the properties of small parts, I used a biscuit tin as a noise chamber. I drilled a hole in the lid to fit an SMA connector and attached my fixture to the inside of the lid. I sanded the lid and tin edge to improve connectivity. With the part to be measured attached to the fixture I closed the tin and made the measurements. It worked quite well. Extending the frequency range where measurements were possible.
|
Re: Interesting phenomenon
Hi Zack,
You said “I believe the AA-600 generates a stronger signal that is sent to the DUT. I have suspected this for some time”
The AA-600 output level is specified as approximately-10dBm into a 50 ohm load and some models of the NanoVNA have a lower output level than that but the NanoVNA-F V3.1 as an example has an output level of 0 dBm into a 50 ohm load which is considerably greater than the AA-600 and that’s one reason I went with that particular model.
Bottom line is that the output level of the NanoVNA series varies between models.
Just FYI,
Don wd8dsb
|
Not sure about the obfuscation, but I guess everyone needs some sort of alter ego.
|
Right!
Anne Ranch is a senator (Yeah sure...???)
Look it up.
|
And his name is Vaclav, not Anne.
Mike - M0MLM
------------------------------------------------------------------------
*From:* Clint Sharp [mailto:cjaysharp@...]
*Sent:* Sunday, 4 June 2023 at 8:24 pm
*Subject:* [nanovna-users] Simple SWR analysis #nanosaver
toggle quoted message
Show quoted text
You posted incorrect information stating that the software was no longer
updated, I did the simplest thing, went and looked at the repository and,
sure enough, it proves you wrong.
'Connecting' to the source is as simple as opening a webpage, yet that
seems beyond you, someone who claims to be a python developer.
You argue endlessly to pollute the list, won't accept that your statement
was wrong and have changed your argument at least twice that I can see.
So, my conclusion, you're nothing more than a troll.
Saldy I'm not list admin or you'd be on a timeout, so, instead, I have now
created a filter to delete your posts from my mailbox immediately, you add
nothing of value that I can't find elsewhere.
On Sat, 3 Jun 2023 at 09:00, Anne Ranch<anneranch2442@...> wrote:
On Wed, May 31, 2023 at 10:17 AM, Clint Sharp wrote:
I see updates, patches and fixes in the github repository as recently as 3
weeks ago for Nanovnasaver.
and where is the logic of your post , if I am allowed to ask ?
The issue is CONNECTING to the source (code) to USE these "updates,
patches and fixes..."
|
You posted incorrect information stating that the software was no longer
updated, I did the simplest thing, went and looked at the repository and,
sure enough, it proves you wrong.
'Connecting' to the source is as simple as opening a webpage, yet that
seems beyond you, someone who claims to be a python developer.
You argue endlessly to pollute the list, won't accept that your statement
was wrong and have changed your argument at least twice that I can see.
So, my conclusion, you're nothing more than a troll.
Saldy I'm not list admin or you'd be on a timeout, so, instead, I have now
created a filter to delete your posts from my mailbox immediately, you add
nothing of value that I can't find elsewhere.
toggle quoted message
Show quoted text
On Sat, 3 Jun 2023 at 09:00, Anne Ranch <anneranch2442@...> wrote: On Wed, May 31, 2023 at 10:17 AM, Clint Sharp wrote:
I see updates, patches and fixes in the github repository as recently as
3
weeks ago for Nanovnasaver.
and where is the logic of your post , if I am allowed to ask ?
The issue is CONNECTING to the source (code) to USE these "updates,
patches and fixes..."
--
Clint. M0UAW IO83
*No trees were harmed in the sending of this mail. However, a large number
of electrons were greatly inconvenienced.*
|
Re: Interesting phenomenon
This is where the professional devices excel.? I have an Anritsu SiteMaster and a CellMaster that have the capability of ignoring these extraneous signals. The Anritsu devices send a coded signal up the coax and only use that coded reflected signal to make measurements.? This is almost a necessity at highly Rf populated sites that I occasionally do work at, especially if you are sweeping an antenna that is in the range of other services on the site.? The exception is when the interfering signal is so strong that it overpowers the coded signal.
Joe
toggle quoted message
Show quoted text
On 6/4/2023 9:40 AM, Siegfried Jackstien wrote: example measure a 40m dipole and have a strong 41m radio station close . yes
even a signal outside of your normal measure range may cause this (think also on harmonics or unwanted mixing products)
dg9bfc sigi
|
Re: Interesting phenomenon
One of the lesser known issues is transmitter sideband noise. No carrier is perfect as it generates noise eithe side of the carrier and if the carrier is very powerful so the sideband noise is considerable. *Clyde K. Spencer* On Sun, Jun 4, 2023 at 9:40?AM Siegfried Jackstien < siegfried.jackstien@...> wrote: example measure a 40m dipole and have a strong 41m radio station close
.. yes
even a signal outside of your normal measure range may cause this (think
also on harmonics or unwanted mixing products)
dg9bfc sigi
Am 03.06.2023 um 23:49 schrieb Zack Widup:
I have been trying to tune some ferrite rod antennas to a specific
frequency. The target frequency is 530 kHz, and for reasons that may be too
complicated to describe here, I want to use a fixed capacitor, not a
variable capacitor. I got some ferrite rods that are 8 inches long and
0.375 inches in diameter. I wound 50 turns of wire on one to give an
inductance of about 300 uH. I tried to measure the inductance of the coil
with my NanoVNA, and found the measured inductance varied depending on
whether the ferrite rod was vertical or horizontal, and changed with
direction that the ferrite rod pointed when horizontal. When I used the
calculated capacitance value to give a resonant frequency of 530 kHz, I
also found that the resonant frequency shown on the NanoVNA seemed to
change when the antenna was vertical vs. horizontal, and varied with
direction of the horizontal position.
This baffled me until I got a hunch and connected the ferrite rod assembly
to my TinySA. A local AM station on 580 kHz was extremely strong in one
direction when the antenna was horizontal, I could null it out at right
angles to that, and with the antenna vertical, a signal was observable but
not that strong. So it appears the signal from the local AM station is
affecting the readings I get on the NanoVNA.
I tried making the same measurements with my RigExpert AA-600, which also
measures resistance, reactance and impedance of circuits. The results
seemed more consistent. I believe the AA-600 generates a stronger signal
that is sent to the DUT. I have suspected this for some time, because I
could get an SWR reading on the AA-600 over 400 feet of coax cable, but
none on the NanoVNA.
I thought I'd send this e-mail as a curiosity of something I discovered. If
you're trying to measure something with the NanoVNA and there is a strong
transmitted signal source nearby close to the frequency you're trying to
measure at, it could affect your readings.
Zack W9SZ
|
Re: Interesting phenomenon
example measure a 40m dipole and have a strong 41m radio station close .. yes
even a signal outside of your normal measure range may cause this (think also on harmonics or unwanted mixing products)
dg9bfc sigi
Am 03.06.2023 um 23:49 schrieb Zack Widup:
toggle quoted message
Show quoted text
I have been trying to tune some ferrite rod antennas to a specific
frequency. The target frequency is 530 kHz, and for reasons that may be too
complicated to describe here, I want to use a fixed capacitor, not a
variable capacitor. I got some ferrite rods that are 8 inches long and
0.375 inches in diameter. I wound 50 turns of wire on one to give an
inductance of about 300 uH. I tried to measure the inductance of the coil
with my NanoVNA, and found the measured inductance varied depending on
whether the ferrite rod was vertical or horizontal, and changed with
direction that the ferrite rod pointed when horizontal. When I used the
calculated capacitance value to give a resonant frequency of 530 kHz, I
also found that the resonant frequency shown on the NanoVNA seemed to
change when the antenna was vertical vs. horizontal, and varied with
direction of the horizontal position.
This baffled me until I got a hunch and connected the ferrite rod assembly
to my TinySA. A local AM station on 580 kHz was extremely strong in one
direction when the antenna was horizontal, I could null it out at right
angles to that, and with the antenna vertical, a signal was observable but
not that strong. So it appears the signal from the local AM station is
affecting the readings I get on the NanoVNA.
I tried making the same measurements with my RigExpert AA-600, which also
measures resistance, reactance and impedance of circuits. The results
seemed more consistent. I believe the AA-600 generates a stronger signal
that is sent to the DUT. I have suspected this for some time, because I
could get an SWR reading on the AA-600 over 400 feet of coax cable, but
none on the NanoVNA.
I thought I'd send this e-mail as a curiosity of something I discovered. If
you're trying to measure something with the NanoVNA and there is a strong
transmitted signal source nearby close to the frequency you're trying to
measure at, it could affect your readings.
Zack W9SZ
|
Re: Interesting phenomenon
I can second that as well !? I inherited some old antennas from a defunct CATV head end and have been trying to take what I thought was the easy way out and sweeping them for resonance with my Nano VHA-H but I can't trust the reading given regardless of calibrations I get a different value each scan LOL.
Wt
toggle quoted message
Show quoted text
On 6/3/2023 7:57 PM, alan victor wrote: Yes Zack. Been there done that. Tried outdoor antenna measurements carting a
hp vector voltmeter and sig gen. Always saw reflected power greater than incident!
Gee an active antenna! Could not get realistic data until I moved to a new measurement
frequency or drove the input power up to over ride the interference.
|
Re: Interesting phenomenon
Yes Zack. Been there done that. Tried outdoor antenna measurements carting a
hp vector voltmeter and sig gen. Always saw reflected power greater than incident!
Gee an active antenna! Could not get realistic data until I moved to a new measurement
frequency or drove the input power up to over ride the interference.
|
I have been trying to tune some ferrite rod antennas to a specific
frequency. The target frequency is 530 kHz, and for reasons that may be too
complicated to describe here, I want to use a fixed capacitor, not a
variable capacitor. I got some ferrite rods that are 8 inches long and
0.375 inches in diameter. I wound 50 turns of wire on one to give an
inductance of about 300 uH. I tried to measure the inductance of the coil
with my NanoVNA, and found the measured inductance varied depending on
whether the ferrite rod was vertical or horizontal, and changed with
direction that the ferrite rod pointed when horizontal. When I used the
calculated capacitance value to give a resonant frequency of 530 kHz, I
also found that the resonant frequency shown on the NanoVNA seemed to
change when the antenna was vertical vs. horizontal, and varied with
direction of the horizontal position.
This baffled me until I got a hunch and connected the ferrite rod assembly
to my TinySA. A local AM station on 580 kHz was extremely strong in one
direction when the antenna was horizontal, I could null it out at right
angles to that, and with the antenna vertical, a signal was observable but
not that strong. So it appears the signal from the local AM station is
affecting the readings I get on the NanoVNA.
I tried making the same measurements with my RigExpert AA-600, which also
measures resistance, reactance and impedance of circuits. The results
seemed more consistent. I believe the AA-600 generates a stronger signal
that is sent to the DUT. I have suspected this for some time, because I
could get an SWR reading on the AA-600 over 400 feet of coax cable, but
none on the NanoVNA.
I thought I'd send this e-mail as a curiosity of something I discovered. If
you're trying to measure something with the NanoVNA and there is a strong
transmitted signal source nearby close to the frequency you're trying to
measure at, it could affect your readings.
Zack W9SZ
|
The other adaptation solution and the corresponding Eznec file
The intermediate impedance must then be : 81 -j71 ?
Does anyone have a ready-made software to calculate this or then it will be necessary that I code it myself ?
73
--
F1AMM
Fran?ois
|
Re: measuring transformers - Re: [nanovna-users] Zo of twisted pair
On Fri, Jun 2, 2023 at 09:00 AM, Jim Lux wrote:
And this is where going to fancier tools might make life easier.
( #window-223109388 )
Of course. If the technique is not applicable to your situation, look elsewhere. For other situations, characterizing a system's performance (e.g. DM and CM) using cascaded S-Parameter files can be useful.
|
On Sat, Jun 3, 2023 at 09:55 AM, Anne Ranch wrote:
I really need to read the source code
You really need to clarify which version of saver you're using, if it is an old version, then it could be out of sync with the improved NanoVNA firmware.
|
On Sat, Jun 3, 2023 at 10:00 AM, Anne Ranch wrote:
The issue is CONNECTING to the source (code) to USE these "updates, patches
and fixes..."
If you look at the "About window, don't you see this line? "For further details, see: Just click on the URL and you'll enter the home page where you can download the latest, greatest releases and where you also have the possibility to announce your complaint about not working details - just as I did in my bug report that I raised as a service also for you. That's the way open source works, you take the software and give something back, either code or documentation or concise error reports.
|
Ah, a French :)
Hello
I advanced a little on the subject. To simplify, I will already give the almost satisfactory response. The base of the antenna is :
- Frequency = 3.647 MHz Impedance = 120.79 + J 41.13 Ohms
- Frequency = 7.1 MHz Impedance = 201.6 - J 212.3 Ohms
I cascaded one behind the other, starting from the antenna to the TX
- A low pass adapter (granted on 7.1 MHz)
- A high pass adapter (granted on 3.65 MHz)
Regarding the adapter passes high, the closest to the TX, I fix that at 3.65 MHz I want it to bring 50 ?. It will therefore bring 50 ?. Obviously at 7.1 MHz, it brings back an impedance which is not 50 ?
In the simplified (and inaccurate) calculation I imposed that the "low pass addator, that on the side of the antenna brings back to 7.1 MHz 50 ?
To optimize I made sure that the impedances brought back by this low pass serve from the entrance to the top pass adapter.
The objective was, on the TX side that we see 50 ? for 3.65 MHz and 7.1 MHz. In fact is to adjust the intermediate impadance between the two adapters (impadance that I have arbitrarily fixed at 50 ?) and here is the result
ROS 3,650: 1.00
ROS 7,100: 1.02
The adapter diagram is attached (Ok.png).
Here is where I am.
- Either someone has already treated this case and there is a calculation module
- Either this module does not have (or it cannot be found) and I will write code to resolve the network by sweeping the values of this intermediate impedance.
In the example it is 62 + j32
As the Excel file is small, I have it, attached. The problem is that it is not an operational calculation sheet (armored) but the calculations are from. 62+j32 are in the Q5 and Q6 cells of the sheet "Ajusté"
73
--
F1AMM
Fran?ois
toggle quoted message
Show quoted text
-----Message d'origine----- De la part de F6EGK - Jean- Envoyé : samedi 3 juin 2023 09:08
|
On Fri, Jun 2, 2023 at 08:02 PM, Jim Lux wrote:
Either you have enough buffer on the receiving end, or "stuff happens".
Which does not makes sense. The example I mentioned has plenty of data samples when the range is 400 to 500 and it works as expected , but with LESS data to process , when the range is much narrower - it bombs out. Worse yet - it does not recover... I really need to read the source code , python or no python....
|
Hi Fran?ois,
When you do matching HP and LP calculations, you get perfect results at targeted frequencies. That's ok, but don't forget that at 7,1 MHz, you are not in the flat transfer part for HP network. So you get small mismatch and loss at this frequency. Demonstration below with SimSmith.
You don't give us details about your two matching cells, but schematic is probably as drawn in picture HP_LP.
First report : your LP cell is absolutely useless, simply as at 7,1 MHz the complex impedance is already 50 Ohms (50.01 +0j). Values for L1 and C1 are also not realistic at these frequencies. So keep only the HP cell, as drawn in picture HP-only.
Second report : No change for SWR value (1,64) at 7,1 MHz without the LP cell (normal behavior). This value is also comparable to what can be found in your s1p file at 7,1 MHz (SWR = 1,62). The Bode plot (BodePlot picture) highlights loss (0,3 dB) and mismatch (SWR = 1,64) values.
73 - Jean-Roger
|
On 6/2/23 5:14 PM, Anne Ranch wrote: That is pretty good analysis of what maybe happening.
I have not noticed the "saver" posts the port baud rate. It really doesn't matter - the baud rate is a fiction for serial over USB. it's a software fiction that makes a USB link look like a serial interface. Even if the baud rate is on borderline of the system ability the
RS232 protocol should be able to control the its data flow. Nope - there's no XON/XOFF or CTS/RTS kind of flow control. For "USB emulating serial" (which is the case on both ends of the link) it's not really RS232. So the 115.2 kbps is sort of a bogus number. It's mapped into packets traversing the USB and those packets are sequenced into a 8 kHz slotting system. Either you have enough buffer on the receiving end, or "stuff happens".
|
Ho-Ro
