Ok sorry to be such a pain.
I really want to get this up and rolling for field day and some demonstrations coming up and I feel like a idiot for not catching on.
Thanks for being so patient with me.
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Mike,
Just set the start and stop frequencies to the widest approximate frequency range where you expect the antenna will be tuned to. For 10M try 25 to 32 MHz. The calibrate for this range. Set the yellow trace to read SWR and you should see a frequency where the SWR is at a minimum. Then use the rocker switch to move the marker to this point and you can read the frequency and SWR. Then slowly adjust your coil and you should see the SWR minimum move. You can "zoom in" by setting the start a bit higher and the stop a bit lower and the NanoVNA will interpolate the calibration.
Roger
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Ok Roger, ? I watched the video but didn't glean a lot of learning from it. I'm not understanding were he is reading his freq from ? ?
At the moment I'm trying to set the coil in the center of the 10m band so I have a reference point of were I need to start for the rest of the bands but I'm not understanding something ?
In very simple terms, is there a way to set the vna look at what freq the antenna is matched at (ok its off so I need to make the coil shorter or longer to get to my freq) move the coil check the reading (ok that was the wrong direction, move THE PICKUP a few clicks the other way on the coil)
This is frustrating me because I'm sure its a simple process but I'm totally flubbing it up ?
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Re: Firmware upgrade for original nanovna
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Re: NanoVNA-H not seen by windows11 (no com port)
#nanovna-h
Dear Roger,
thank you very much for reply. In the meanwhile problem solved, it was the usb cable which was interrupted inspite of looking like brand new.
That is why I thought that might be a W11 driver problem. Thank you again, wish you all the best.
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Firmware upgrade for original nanovna
Hi
I have a NanoVNA with version 0.8.0 firmware Dated June 2020. Is there a later version for this early NanoVna?
If so are ther some instructions somewhere. I did this in 2020 and it seemed straightforward but I seem to be struggling to find the right info at the moment.
regards
Don
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Mike G8GYW. This VA5 sounds pretty good from the write up in their web page. Is it good enough to be the only 1 in your kit for a while?
Ed
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Re: Estimating coaxial cable length - using TDR
Jim VE7RF
See / read the original post
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Re: Estimating coaxial cable length - using TDR
I don't know the OP's reasons for wanting to know but I'd think it useful
for knowing how much is used on a run, how much is left on a reel and for
tracking down faults to think of just a few.
"Precise" is of course variable by application, from back when 10b2
ethernet was a thing and dinosaurs roamed the earth within a metre was
excellent because I can eyeball and inspect for faults at that sort of
distance, YMMV.
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On Mon, 12 Jun 2023, 07:35 Jim VE7RF, <jim.thom@...> wrote: I'm trying to fathom the reason for knowing the exact physical length of
a piece of coax, or it's exact electrical length. What are you trying to
do here, phase yagis on 14 mhz.... or building a 4 square vertical array
for 80m ?
Even if building stacked yagis, and the coax is all coming off the same
reel, it's a moot point. All that is required is equal lengths of coax
from the L network, to each yagi.
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Re: Estimating coaxial cable length - using TDR
I'm trying to fathom the reason for knowing the exact physical length of a piece of coax, or it's exact electrical length. What are you trying to do here, phase yagis on 14 mhz.... or building a 4 square vertical array for 80m ?
Even if building stacked yagis, and the coax is all coming off the same reel, it's a moot point. All that is required is equal lengths of coax from the L network, to each yagi.
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Re: Anybody happens to know VF of this cable ?
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Thank you, Jim. Much appreciated. -- Rich WB2GXM------ Original message------From: Jim LuxDate: Sun, Jun 11, 2023 8:33 PMTo: [email protected];Roger Need via groups.io;Cc: Subject:Re: [nanovna-users] Anybody happens to know VF of this cable ?On 6/11/23 4:23 PM, Richard Spohn wrote: Ok, you said "there are several ways to determine the actual VF of a cable using a NanoVNA". WHY did you stop there? Dispense with the attitude and just TELL US what these methods are!!- 1) use the NanoVNA to sweep and find out where 1/4 wavelength is (i.e. peak in S11 magnitude). Knowing the frequency where it's 1/4 wavelength, you can compare to free space wavelength. 2) Use the NanoVNA to measure the phase shift of the reflection at multiple frequencies, and then fit a straight line to the measurements, after unwrapping the phase. 3) Use the TDR function of the NanoVNA. All of these use a known length of cable, then you measure the electrical length of that length, and the ratio is the VF.
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Thanks Roger and everyone else that is helping me learn on this journey. Eventually I'll get it all locked down and be able to pay it forward I hope ?
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Re: Anybody happens to know VF of this cable ?
On 6/11/23 4:23 PM, Richard Spohn wrote: Ok, you said "there are several ways to determine the actual VF of a cable using a NanoVNA". WHY did you stop there? Dispense with the attitude and just TELL US what these methods are!!- 1) use the NanoVNA to sweep and find out where 1/4 wavelength is (i.e. peak in S11 magnitude). Knowing the frequency where it's 1/4 wavelength, you can compare to free space wavelength. 2) Use the NanoVNA to measure the phase shift of the reflection at multiple frequencies, and then fit a straight line to the measurements, after unwrapping the phase. 3) Use the TDR function of the NanoVNA. All of these use a known length of cable, then you measure the electrical length of that length, and the ratio is the VF.
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On Sun, Jun 11, 2023 at 12:28 PM, Mike Anderson/KF?AWL wrote:
Ok now, is there a easy way to figure out the resonance of the antenna?
I'm useing a different whip and ground plane so the factory (height) on the
coil is going to be off so I'm wondering if there is a easy way to get a idea
of where the coil is setting the antenna up at.
Mike, W2AEW has an excellent series of videos on how to use the NanoVNA to measure and adjust antennas. I think you will find this one worth watching. Roger
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Re: NanoVNA-H not seen by windows11 (no com port)
#nanovna-h
On Sun, Jun 11, 2023 at 12:22 PM, <ciungan.marius@...> wrote: I have a NanoVNA-H wich used to work under W10 with Nanosaver app. After
upgrade to W11, when I connect the NanoVNA to usb port nothing happens, no new
com port is seen under device manager.
Wonder if anyone had the same problem. Any help its welcome.
thank you.
If you can't see the NanoVNA-H as a COM port in Windows 11 after plugging it in that means that the driver is not installed. Windows 11 should install it automatically but sometimes it fails to load. It could be sitting in your "Optional Updates" and you need to select it for installation. Use the search box to find "Windows Update" and select it. Then go to "Advanced Settings" and select "Optional Updates" (see screenshot below). You may find the driver is there waiting to be installed. Some drivers will not install in Windows 11 because "Memory Integrity" is on and the driver does not meet Microsoft safety standards. If you turn off Memory Integrity the driver can then be installed. Roger
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Re: Anybody happens to know VF of this cable ?
Very good point about actual VF vs published VF. There are several ways to quickly get the actual VF of the cable using a NanoVNA but the OP ("Anne") doesn't like posts that go beyond specifically answering her question.
OK, humor me and tel me TWO of several ways to ":get the actual VF of the cable using a NanoVNA"
PS
According to last test - my " digital ( other superlatives intentionally removed ) RG6" VF is .66 !
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Re: Estimating coaxial cable length - using TDR
Roy J. Tellason, Sr
It looks as "this TDR" subject has life of its own,,,
The Agilent article will take me some time to digest...
At present I am trying to "run the source code of nanoVNASaver" in Qt debug mode.
Tentatively I will try to make "TDR" and "TDR display " to match...
My last test - finding known length of my "fancy digital RG6" of VF . 82 ( VF value thanks to the group replies, appreciate that )
matches my inch stick when I set the VF to .66 !
So... is it real or Memorex?
Is my fancy RG6 mislabeled and it is really plain RG6 of .66 VF?
Where is the problem ?
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Re: Anybody happens to know VF of this cable ?
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Ok, you said "there are several ways to determine the actual VF of a cable using a NanoVNA". WHY did you stop there? Dispense with the attitude and just TELL US what these methods are!!------ Original message------From: Roger Need via groups.ioDate: Sun, Jun 11, 2023 3:05 PMTo: [email protected];Cc: Subject:Re: [nanovna-users] Anybody happens to know VF of this cable ?On Sun, Jun 11, 2023 at 11:59 AM, Joe WB9SBD wrote:
Now something to remember,
The VF can be FAR from that spec.
I have seen Brand New cables that were different THAN THE SPECIFIED VALUE.
And as cables age, and it seems this stuff is OLD, that it changes
sometimes a LOT as it gets older!
Joe, Very good point about actual VF vs published VF. There are several ways to quickly get the actual VF of the cable using a NanoVNA but the OP ("Anne") doesn't like posts that go beyond specifically answering her question. Roger
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Re: Estimating coaxial cable length - using TDR
On Saturday 10 June 2023 02:04:13 pm Roger Need via groups.io wrote: For more details on how the S11/IFFT method of TDR works this tutorial by Agilent is quite informative. ?It includes details on why "windowing" the data is necessary, how to determine the upper stop frequency required based on estimated cable length, why the lower start frequency should be close to DC and other considerations.
Some intersting reading, there. -- 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: When I connect NanoVNA Saa-2N to the USB-port
Sorry, it was the USB-cable. Should have used the one included.
-Oddleiv
s?n. 11. juni 2023 kl. 14:33 skrev Oddleiv Tungland <oddleiv@...>:
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s?n. 11. juni 2023 kl. 14:27 skrev Oddleiv Tungland <oddleiv@...>:
the display starts to flicker.
-Oddleiv
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Mike Anderson/KF?AWL
Roger Need
