Re: where is the end fed natural resonance
How you define efficiency? If there¡¯s no loss, then an infinitely small antenna (a hertzian dipole, for instance) just has 1.5 dB gain over an isotropic antenna. Small antennas have low radiation resistance, but that only affects efficiency if there¡¯s loss.
For the run of the mill, nearly full sized, dipole, whether or not it¡¯s resonant doesn¡¯t change the radiation resistance much, neither does it change the loss resistance, so the efficiency doesn¡¯t change much.
What might change is the loss in the matching network or feedline.
The compact loop is notorious for having high loss because it has low radiation resistance compared to loss resistance. As is a mobile whip on 40 meters and down - they¡¯re a tiny fraction of a wavelength, so the radiation resistance is low.
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On Mar 4, 2024, at 1:01?PM, W0LEV <davearea51a@...> wrote:
?QUOTE (Jim Lux): .....short antennas have a different pattern than full
size antenna, but their "efficiency" isn't intrinsically different).
Jim, if we address small tuned loops on transmit, the efficiency over a
dipole radiator is considerably less, in round numbers, -20 dB.
In the limit of a point radiator (if it could radiate) - a true isotropic
source, the efficiency is zip, zero.
Dave - W?LEV
On Mon, Mar 4, 2024 at 7:28?PM Jim Lux <jimlux@...> wrote:
This is using resonance as a choke, not resonance of the entire antenna.
You want your choke to be high Z, so that currents don't flow on the
outside of the coax.
As far as the antenna goes, if you can drive it or couple power to/from
it, whether it's resonant or not makes no difference on the performance.
(aside from any other length related issues - short antennas have a
different pattern than full size antenna, but their "efficiency" isn't
intrinsically different).
-----Original Message-----
From: <[email protected]>
Sent: Mar 4, 2024 9:54 AM
To: <[email protected]>
Subject: Re: [nanovna-users] where is the end fed natural resonance
But then ARRL Antenna book says resonance has no affect on antenna
performance. Hams like to operate antennas at or near resonance as
that’s where drive point impedance is at its lowest value so
it’s easier to match,
Ray
--
*Dave - W?LEV*
--
Dave - W?LEV
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Re: DFU drivers not loading
Exactly which flavor nanovna do you have?
What prompted the need for DFU mode? Secondary to physical damage like deceleration trauma or charging damage?? The more info the better.
Jason Burchell
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On Mar 4, 2024, at 11:25?AM, Roger Need via groups.io <sailtamarack@...> wrote:
?On Sun, Mar 3, 2024 at 01:58 PM, John Mazzone wrote:
I cant get the DFU driver to work. WIN11 opsys.
I tried all the procedures in the "absolute beginner guide" but no dice.
/g/nanovna-users/message/33097
Roger
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Re: Question on remote use of NanoVNA
It's also pretty easy to set up a battery powered access point that everyone can connect to. In a Field Day scenario, this is handy for logging, and backups and such, because you can hang a backup drive off the access point. And in Field Day, if you're out in the field, WiFi works at more distance (because there's not interfering networks)
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-----Original Message----- From: < [email protected]> Sent: Mar 4, 2024 1:24 PM To: < [email protected]> Subject: Re: [nanovna-users] Question on remote use of NanoVNA The Samsung S4 connected right up with the H with the TCPUART app. When it came to the server portion I had also checked the box to use the connection by default. On my Lenovo ideapad running Win 10 and the NanoVNA-app 1.1.208 I connected to the phone and could run a continuous feed without problem. I'd call that a victory. This functionality is pretty cool. I do get my house wifi through most of my yard so the connectivity issue would only really come up during field day setups. I'm still going to tinker and see what I can. Creating a wifi hotspot should be do-able I'd think. Thanks all, Andy
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Re: Question on remote use of NanoVNA
The Samsung S4 connected right up with the H with the TCPUART app. When it came to the server portion I had also checked the box to use the connection by default.
On my Lenovo ideapad running Win 10 and the NanoVNA-app 1.1.208 I connected to the phone and could run a continuous feed without problem. I'd call that a victory.
This functionality is pretty cool. I do get my house wifi through most of my yard so the connectivity issue would only really come up during field day setups. I'm still going to tinker and see what I can. Creating a wifi hotspot should be do-able I'd think.
Thanks all,
Andy
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Re: where is the end fed natural resonance
QUOTE (Jim Lux): .....short antennas have a different pattern than full
size antenna, but their "efficiency" isn't intrinsically different).
Jim, if we address small tuned loops on transmit, the efficiency over a
dipole radiator is considerably less, in round numbers, -20 dB.
In the limit of a point radiator (if it could radiate) - a true isotropic
source, the efficiency is zip, zero.
Dave - W?LEV
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On Mon, Mar 4, 2024 at 7:28?PM Jim Lux <jimlux@...> wrote: This is using resonance as a choke, not resonance of the entire antenna.
You want your choke to be high Z, so that currents don't flow on the
outside of the coax.
As far as the antenna goes, if you can drive it or couple power to/from
it, whether it's resonant or not makes no difference on the performance.
(aside from any other length related issues - short antennas have a
different pattern than full size antenna, but their "efficiency" isn't
intrinsically different).
-----Original Message-----
From: <[email protected]>
Sent: Mar 4, 2024 9:54 AM
To: <[email protected]>
Subject: Re: [nanovna-users] where is the end fed natural resonance
But then ARRL Antenna book says resonance has no affect on antenna
performance. Hams like to operate antennas at or near resonance as
that’s where drive point impedance is at its lowest value so
it’s easier to match,
Ray
-- *Dave - W?LEV*
--
Dave - W?LEV
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Re: Question on remote use of NanoVNA
The TCPUART app enables a simple TCP connection to the IP network, so it should work with any method of getting your phone and the computer on a network with the same IP address space, ad-hoc or peer-to-peer or whatever. I just used my home wifi because that was easiest (my computer already was on that network). Using hotspot mode may work, but some phones require a cellular connection to get the phone to activate a hotspot (since the normal intent of hotspot software is to bridge the wifi to the cell connection to the network).
And correct, my OTG adaptor is for the phone, not the nano. It is an old one I used with an old Samsung tablet I had, to attach external devices.
Good luck, and let us know what you find out.
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Re: where is the end fed natural resonance
This is using resonance as a choke, not resonance of the entire antenna.
You want your choke to be high Z, so that currents don't flow on the outside of the coax.
As far as the antenna goes, if you can drive it or couple power to/from it, whether it's resonant or not makes no difference on the performance. (aside from any other length related issues - short antennas have a different pattern than full size antenna, but their "efficiency" isn't intrinsically different).
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-----Original Message----- From: < [email protected]> Sent: Mar 4, 2024 9:54 AM To: < [email protected]> Subject: Re: [nanovna-users] where is the end fed natural resonance But then ARRL Antenna book says resonance has no affect on antenna performance. Hams like to operate antennas at or near resonance as that’s where drive point impedance is at its lowest value so it’s easier to match, Ray
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Re: DFU drivers not loading
On Sun, Mar 3, 2024 at 01:58 PM, John Mazzone wrote:
I cant get the DFU driver to work. WIN11 opsys.
I tried all the procedures in the "absolute beginner guide" but no dice.
/g/nanovna-users/message/33097Roger
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Re: Question on remote use of NanoVNA
Yes, if it has the ability to be a hotspot that would work.
An advantage of "connecting both to a network hot spot" as opposed to making the phone a hotspot/AP is that your computer can then hit other places on the network (like the web, or your file server, or email, or...) while you're connected to the NanoVNA.
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-----Original Message----- From: < [email protected]> Sent: Mar 4, 2024 10:39 AM To: < [email protected]> Subject: Re: [nanovna-users] Question on remote use of NanoVNA Jim, I agree. I use the terms access point and hot spot interchangeably. Android or at least the old 5.0.1 version I'm looking at on these ancient Samsung S4's have the ability to turn the phone into a mobile Hotspot. Allowing sharing and file and data transfer would also have to be turned on. So it sounds promising I just need time to play and confirm how that will pair with TCPUART. Andy
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Re: Question on remote use of NanoVNA
Jim,
I agree. I use the terms access point and hot spot interchangeably. Android or at least the old 5.0.1 version I'm looking at on these ancient Samsung S4's have the ability to turn the phone into a mobile Hotspot. Allowing sharing and file and data transfer would also have to be turned on. So it sounds promising I just need time to play and confirm how that will pair with TCPUART.
Andy
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Re: where is the end fed natural resonance
But then ARRL Antenna book says resonance has no affect on antenna performance. Hams like to operate antennas at or near resonance as that¡¯s where drive point impedance is at its lowest value so it¡¯s easier to match,
Ray
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Re: Question on remote use of NanoVNA
It would be a ¡°IP network connection¡±, so both ends need to be ¡°on the network¡±, whether by WiFi or wired.
If you could set up one end as an ¡°access point¡± and the other could connect to it, that would work.
It¡¯s been a long time since I¡¯ve seen WiFi in ad-hoc mode, rather than in ¡°infrastructure¡± mode (access point). However, if both ends are set up that way (which might also require assigning static IP addresses) no reason it shouldn¡¯t work.
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On Mar 4, 2024, at 4:35?AM, Andrew Harman <Nexus9d9@...> wrote:
?Stan,
I pulled out an assortment of cell phones last night. Three were Samsung Galaxy S4's, an LTE A910. The S4's should work even though Android 5, the TCPUART program says its good back to 3.5. You do have an unusual OTG there. I've had similar connection issues with a dirty port.
With this software the OTG goes to the cell side of the cable (as you've shown) and throws the phone from being a peripheral to being into a host. I believe your wording indicated that your connection was dependent on your home wifi and not a peer-peer. I have to look at that.
Andy
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Re: Question on remote use of NanoVNA
Stan,
I pulled out an assortment of cell phones last night. Three were Samsung Galaxy S4's, an LTE A910. The S4's should work even though Android 5, the TCPUART program says its good back to 3.5. You do have an unusual OTG there. I've had similar connection issues with a dirty port.
With this software the OTG goes to the cell side of the cable (as you've shown) and throws the phone from being a peripheral to being into a host. I believe your wording indicated that your connection was dependent on your home wifi and not a peer-peer. I have to look at that.
Andy
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Re: Which version of the firmware supports rotary encoders
This was discussed 4 years ago and the developer(s) decided not to implement it since you also have the touch screen and at the time, code storage on the original devices was at a premium. A few owners decided to add push buttons instead. Have a look in the WIKI: /g/nanovna-users/wiki/13194#Buttons-and-switchesAlso have a look in the FILES area under mods.
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Re: NanoVNA-H4 | SWR spikes non only at 300MHz, but also around 500 MHz
Hi Bob,
It is now at 295 and working good. Default it was slightly (100Hz) above 300MHz.
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Re: Question on remote use of NanoVNA
I hope you can make it work as easily as I did. My cable was a bit flaky, so the first few times I tries to connect to the vna, it said it couldn't connect, unknown device. But then I plugged the cable into the phone better, and it worked just fine. Here is a photo of my simple setup.
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I cant get the DFU driver to work. WIN11 opsys.
I tried all the procedures in the "absolute beginner guide" but no dice.
Any suggestions?
--
John Mazzone
AMVETS Post 826, Life Member.
American Legion Post 150.
jmazzone@...
john.mazzone@...
Cell 845-389-2874 text or voice
--
This email has been checked for viruses by Avast antivirus software.
www.avast.com
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Re: where is the end fed natural resonance
Parallel resonance yields the most isolation between the antenna and the coax feedline. SHUNT PARALLEL RESONANCE = HIGH-Z OPEN SHUNT SERIES RESONANCE = LOW-Z SHORT Use your NANOVNA to prove that. Dave - W?LEV On Sun, Mar 3, 2024 at 7:53?PM Ray W8LYJ via groups.io <rcbenedict1545= [email protected]> wrote: Why resonate???
Ray
w8LYJ
-- *Dave - W?LEV* -- Dave - W?LEV
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Re: Question on remote use of NanoVNA
Stan Dye,
Thank you so much for that feed back. It helps. I have a few older cell's here to play with.
Andy
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Re: where is the end fed natural resonance
On Sun, Mar 3, 2024 at 11:04 AM, W0LEV wrote:
But given the small difference between the S21 and the Y21 method, I'll
continue with the S21 method.
It's not always small, Dave. The first plot shows VNA R & X for data from a ground probe using a two-port series measurement. The second plot shows the resulting ground permittivity and conductivity. Dim traces are for the S21 method, normal traces are for Y21. The Y21 permittivity and conductivity traces are similar to those derived from a single-port S11 measurement. The traces for the S21 method are in left field. In this application, common-mode current arises because the unknown (ground) is distributed and easily couples to the VNA cables and the VNA itself. It manifests itself as rather large stray shunt impedances. The Y21 method effectively null them. Brian
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Jason Burchell
Roger Need
ErnestB
