Re: Ubuntu PPA or .deb installation
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Re: Ubuntu PPA or .deb installation
I created an issue on GitHub regarding your proposal:
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Re: Common ground and 2-port measuring
Hi Victor,
Thank you for your update and information.
There are different ways to measure CMC performance as there are different 'lumped' component models of a CMC taking account of parasitic elements of a practical or real component.
There is merit in making a test configuration and method for how the component will be used in a particular application. If I were designing and making a CMC filter, I would use a different method of testing to my simple proposal, one very similar to your preferred configuration.
I do not have any rf 1:1 center-tapped baluns so am not able to compare results. If and when you have time to make comparisons, I would be very interested in your findings.
Kind regards
Ed, G8FAX
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Re: Should I upgrade firmware, and if so which version to use?
Of course you should still upgrade to the latest. You will get bug fixes, performance improvements, and new features. FREE! 73 -Jim NU0C On Mon, 11 Jul 2022 10:50:32 -0700 m2walter@... wrote: You're correct. I was thinking about it and tried it: the NanoVNA does go to 900 MHZ. And all this time I thought that since the default stop freq that it 'boots up with' is 250 Mhz that it was not capable of going higher. That will teach me to test before opening my mouth.
This makes me feel better: less worried 'bout changing firmware.
Mark Walter
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Re: Common ground and 2-port measuring
A clasic way to explain this was to connect 2 ports with coax,
connect the coax shields on 2 ports with a short piece of wire and
try to measure the current in the wire but I like this graphic, it is quite
intuitive.
toggle quoted message
Show quoted text
On Mon, 11 Jul 2022 at 23:52, DP <dpoinsett@...> wrote: On Sun, Jul 10, 2022 at 08:09 PM, Jerry Stuckle wrote:
Actually, that's a common, but incorrect statement. Current - RF or otherwise
- always flows along ALL available paths, split according to the inverse of
the resistance.
//
Jerry, AI0K
Hi Jerry,
You're absolutely right. It's not all or nothing. A semantically better
way to say it is: RF current always favors the path of least impedance. The
degree of "favor" is divided between paths according to impedance. That's
consistent with your point.
In the case of Miro's original question about problems with RF current
flowing in the internal ground connection between the ports, the answer is
still no. The impedance in PATH1 of his drawing (attached) is too high for
there to be a problem even though the DC resistance is probably very low.
The RF return current is confined almost entirely in the transmission line.
The attached drawing shows a double-sided PCB. The bottom has a solid
copper ground plane. The top has a single trace between the ports. An RF
input signal is applied between the trace and ground plane. The load is
connected between the trace and ground plane.
At 10 MHz the RF return current will be confined to a narrow path in the
ground plane directly below the top trace. Openings in the PCB provide
isolated current paths A and B for easy measurement. RF current in these
paths will be negligible.
At RF frequencies, the impedance through paths A and B is high primarily
due to the geometry. The further the distance from the trace, the higher
the series inductance and the lower the parallel capacitance. These both
mean higher reactance. The area in the ground plane directly below the
trace has the lowest impedance. That's where almost all the return current
flows even though it's surrounded by an area with very low DC resistance.
Like so many things with RF, this behavior is counter-intuitive to our
understanding of what happens with DC and low-frequency AC.
Dave NU8A
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Re: Common ground and 2-port measuring
On Sun, Jul 10, 2022 at 08:09 PM, Jerry Stuckle wrote: Actually, that's a common, but incorrect statement. Current - RF or otherwise
- always flows along ALL available paths, split according to the inverse of
the resistance.
//
Jerry, AI0K
Hi Jerry, You're absolutely right. It's not all or nothing. A semantically better way to say it is: RF current always favors the path of least impedance. The degree of "favor" is divided between paths according to impedance. That's consistent with your point. In the case of Miro's original question about problems with RF current flowing in the internal ground connection between the ports, the answer is still no. The impedance in PATH1 of his drawing (attached) is too high for there to be a problem even though the DC resistance is probably very low. The RF return current is confined almost entirely in the transmission line. The attached drawing shows a double-sided PCB. The bottom has a solid copper ground plane. The top has a single trace between the ports. An RF input signal is applied between the trace and ground plane. The load is connected between the trace and ground plane. At 10 MHz the RF return current will be confined to a narrow path in the ground plane directly below the top trace. Openings in the PCB provide isolated current paths A and B for easy measurement. RF current in these paths will be negligible. At RF frequencies, the impedance through paths A and B is high primarily due to the geometry. The further the distance from the trace, the higher the series inductance and the lower the parallel capacitance. These both mean higher reactance. The area in the ground plane directly below the trace has the lowest impedance. That's where almost all the return current flows even though it's surrounded by an area with very low DC resistance. Like so many things with RF, this behavior is counter-intuitive to our understanding of what happens with DC and low-frequency AC. Dave NU8A
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Re: Perfect SWR with dummy load, but huge with antenna
The measure of a "good" antenna is how well it performs. When I lived in a house with a lot bigger yard a few years ago I had a 40 meter vertical full-wave loop antenna (~12 feet high and ~58 feet long). It had 5.5 dB of gain over a dipole according to NEC2. It performed almost as well as a 40 meter Yagi antenna in its peak directions. It was the best 40 meter antenna I have owned. I now live on a much smaller property and can't fit that antenna in the yard. I have an MFJ 1796 vertical. It does "OK" on 20 meters and higher, but I'm severely disappointed in its performance on 40 meters. Maybe the other antenna spoiled me. Zack W9SZ On Mon, Jul 11, 2022 at 12:14 PM W0LEV <davearea51a@...> wrote: Yes, indeed...... The measure of a "good" antenna is not SWR.
Of course, a 1:1 in a 50-ohm non-reactive system is essential to keep the
transmitter output stage happy, but does not measure how good an antenna is
at radiating the RF energy fed to it. Again,......SWR is NOT a single
proper indicator of a "good" antenna.
Dave - W?LEV
On Mon, Jul 11, 2022 at 6:34 AM olivier LAVAUX <f6cng.68@...> wrote:
be careful not to have a dummy load @swr1.1!
what is important is the radiated power! so not only check SWR but also
radiated electromagnetic field!
73
F6CNG Olivier
Le mer. 6 juil. 2022 ¨¤ 10:24, olivier LAVAUX via groups.io <f6cng.68=
[email protected]> a ¨¦crit :
Fitst check continuity before all with and without short circuit on the
antenna itself!
73 Olivier F6CNG
Le dim. 3 juil. 2022 ¨¤ 09:21, Lucian <lucian@...> a ¨¦crit :
Thanks, but you were too quick to dismiss the human factor..
It wasn't until this morning that I realised the antenna is rp-sma female
and the nanovna is sma female.. They will screw in perfectly, yet no
core
contact... facepalm.
I'll need to buy some adapters.
Have a nice day!
--
*Dave - W?LEV*
*Just Let Darwin Work*
--
Dave - W?LEV
<> Virus-free. www.avg.com <> <#DAB4FAD8-2DD7-40BB-A1B8-4E2AA1F9FDF2>
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Re: Should I upgrade firmware, and if so which version to use?
You're correct. I was thinking about it and tried it: the NanoVNA does go to 900 MHZ. And all this time I thought that since the default stop freq that it 'boots up with' is 250 Mhz that it was not capable of going higher. That will teach me to test before opening my mouth.
This makes me feel better: less worried 'bout changing firmware.
Mark Walter
|
Re: Common ground and 2-port measuring
Hello Ed,
I have not much now to look into this, but this article:
Gives your method (Fig 3b and Fig 7a.
So one can measure some aspects of the choke.
I need to check how close this is to the DM mode.
All the best,
Victor
Op ma 11 jul. 2022 om 08:20 schreef Ed G8FAX <ed@...>:
toggle quoted message
Show quoted text
Hi Victor,
Thanks for your feedback, you ask a good question concerning its validity.
I¡¯m not aware of any specific articles on the technique I mentioned, I
derived that configuration from a simple circuit analysis of the
differential mode wiring of a CMC = a series connected circuit with voltage
drop measured across a load resistor.
I¡¯d be interested to hear what concerns you have with my test arrangement.
Kind regards
Ed, G8FAX
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Re: Should I upgrade firmware, and if so which version to use?
it should go to 900 (3rd harmonic) or 1.5 g (fith overtone)
dg9bfc sigi
(sorry i can not help with fw cause i am a v2 user that has a clock to over 4g)
Am 11.07.2022 um 18:44 schrieb m2walter@...:
toggle quoted message
Show quoted text
I have an original NanoVNA: it only goes up to 250 MHz. Can I upgrade the firmware and obtain additional functionality? If the firmware can be upgraded which version should I load. Tks.
Mark Walter
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Re: Perfect SWR with dummy load, but huge with antenna
Yes, indeed...... The measure of a "good" antenna is not SWR.
Of course, a 1:1 in a 50-ohm non-reactive system is essential to keep the
transmitter output stage happy, but does not measure how good an antenna is
at radiating the RF energy fed to it. Again,......SWR is NOT a single
proper indicator of a "good" antenna.
Dave - W?LEV
toggle quoted message
Show quoted text
On Mon, Jul 11, 2022 at 6:34 AM olivier LAVAUX <f6cng.68@...> wrote: be careful not to have a dummy load @swr1.1!
what is important is the radiated power! so not only check SWR but also
radiated electromagnetic field!
73
F6CNG Olivier
Le mer. 6 juil. 2022 ¨¤ 10:24, olivier LAVAUX via groups.io <f6cng.68=
[email protected]> a ¨¦crit :
Fitst check continuity before all with and without short circuit on the
antenna itself!
73 Olivier F6CNG
Le dim. 3 juil. 2022 ¨¤ 09:21, Lucian <lucian@...> a ¨¦crit :
Thanks, but you were too quick to dismiss the human factor..
It wasn't until this morning that I realised the antenna is rp-sma female
and the nanovna is sma female.. They will screw in perfectly, yet no
core
contact... facepalm.
I'll need to buy some adapters.
Have a nice day!
-- *Dave - W?LEV* *Just Let Darwin Work*
--
Dave - W?LEV
|
Should I upgrade firmware, and if so which version to use?
I have an original NanoVNA: it only goes up to 250 MHz. Can I upgrade the firmware and obtain additional functionality? If the firmware can be upgraded which version should I load. Tks.
Mark Walter
|
Re: Ubuntu PPA or .deb installation
|
Re: Ubuntu PPA or .deb installation
I build a deb package with the command "DEB_BUILD_OPTIONS=nocheck python setup.py --command-packages=stdeb.command bdist_deb". You need the debian package "python3-stdeb" (Python to Debian source package conversion plugins for distutils) and maybe some more development packages.
As a quick start see this documentation:
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Re: Perfect SWR with dummy load, but huge with antenna
Yes, you are right, but how do you check radiated electromagnetic field !
Tell us how you do
73
--
F1AMM Fran?ois
toggle quoted message
Show quoted text
-----Message d'origine----- De la part de F6CNG lundi 11 juillet 2022 08:35
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Re: Perfect SWR with dummy load, but huge with antenna
be careful not to have a dummy load @swr1.1! what is important is the radiated power! so not only check SWR but also radiated electromagnetic field! 73 F6CNG Olivier Le mer. 6 juil. 2022 ¨¤ 10:24, olivier LAVAUX via groups.io <f6cng.68= [email protected]> a ¨¦crit : Fitst check continuity before all with and without short circuit on the
antenna itself!
73 Olivier F6CNG
Le dim. 3 juil. 2022 ¨¤ 09:21, Lucian <lucian@...> a ¨¦crit :
Thanks, but you were too quick to dismiss the human factor..
It wasn't until this morning that I realised the antenna is rp-sma female
and the nanovna is sma female.. They will screw in perfectly, yet no core
contact... facepalm.
I'll need to buy some adapters.
Have a nice day!
|
Re: Common ground and 2-port measuring
Hi Victor,
Thanks for your feedback, you ask a good question concerning its validity.
I¡¯m not aware of any specific articles on the technique I mentioned, I derived that configuration from a simple circuit analysis of the differential mode wiring of a CMC = a series connected circuit with voltage drop measured across a load resistor.
I¡¯d be interested to hear what concerns you have with my test arrangement.
Kind regards
Ed, G8FAX
|
Re: Common ground and 2-port measuring
Jerry, Precisely correct, Interestingly, when I first heard that: "always takes the path of least resistance"?statement it was within the context of the propensity of a lightning strike. The tallest, or best grounded?item within range (path of least resistance) typically having a greater chance of being struck during a?lightning storm. However, with regard to normal electrical flow, and function you are 100% correct,?and make a very important point. Current?always flows along ALL available paths, split according?to the?inverse of?the resistance.
toggle quoted message
Show quoted text
On Sunday, July 10, 2022 at 08:09:48 PM EDT, Jerry Stuckle <jerry@...> wrote:
Actually, that's a common, but incorrect statement.? Current - RF or otherwise - always flows along ALL available paths, split according to the inverse of the resistance.
To make it simple, let's say there are two paths.? One has 10 ohms resistance and one has 5 ohms resistance.? If you apply 10V to the circuit, 1amp will flow though the first path and 2 amps though the second path.?
The same goes for milliohm paths like those found in grounds.
Jerry, AI0K
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Re: Common ground and 2-port measuring
Actually, that's a common, but incorrect statement. Current - RF or otherwise - always flows along ALL available paths, split according to the inverse of the resistance.
To make it simple, let's say there are two paths. One has 10 ohms resistance and one has 5 ohms resistance. If you apply 10V to the circuit, 1amp will flow though the first path and 2 amps though the second path.
The same goes for milliohm paths like those found in grounds.
Jerry, AI0K
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Re: Common ground and 2-port measuring
Tnx Dave!
Nice and short write-up of what's happening.
73
Arie PA3A
Op 8-7-2022 om 19:57 schreef DP:
toggle quoted message
Show quoted text
RF return current always flows via the path of least reactance. Here's more info:
Dave NU8A
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Nickko - ON9NG
Ho-Ro
Jim Shorney
Arie Kleingeld PA3A