Re: Different SWR readouts between NanoVNA-H and NanoVNA Saver
I'm finding this conversation very interesting. I'm just getting
up-to-speed with the nanoVNA and thought I understood that the best place
to calibrate for SWR measurement would be close to the transceiver,
including all cabling. What would be the advantage of bypassing the
feedline from the calibration?
In summary, it sounds like if one has a 30m feedline, calibration should be
performed in smaller ranges for the best results, right?
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On Thu, Aug 3, 2023 at 8:59?AM Jim Lux <jimlux@...> wrote: On 8/3/23 5:06 AM, Barry K3EUI wrote:
Steven
Did you do a CALIBRATION for each band, over a fairly narrow frequency range?
I do that, and SAVE the file: 80m CAL, 40m CAL, etc.
I also did one for HF CAL covering 1-30 MHz with with SAVER I can use thousands of cal points and when I save the file, it is maybe 200 kB.
If your SAVER readings are different from the internal readings, I would
first check your CAL files on SAVER.
As mentioned, put the 50 ohm dummy load on and see if the SWR is low
(1:1) on each band you test.
2m and 440 MHz has some additional challenges for the leads and adapters.
de k3eui
Just a comment on Calibration - if you are calibrating at the NanoVNA,
or with short jumpers, then a single wide band cal is probably
sufficient - the interpolation algorithm will find the right values when
you're making narrow sweep range measurements.
BUT, if you're calibrating at the end of long coax (e.g. measuring an
antenna through the feedline), then you might need narrower calibration
ranges, or more properly, more closely spaced calibration points.]
For example if you have 100 ft of coax (call it 30 meters) equivalent
free space length, the feedline puts dips and peaks into the reflection
values that are spaced every 5 MHz.
A 0-500 MHz sweep with 100 points only measures every 5 MHz, so the
interpolation won't necessarily return the right values.
As Barry comments, with NanoVNA Saver (and other tools) you can do a
thousand or more points in your cal, so then it works ok.
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Re: Different SWR readouts between NanoVNA-H and NanoVNA Saver
On 8/3/23 5:06 AM, Barry K3EUI wrote: Steven
Did you do a CALIBRATION for each band, over a fairly narrow frequency range?
I do that, and SAVE the file: 80m CAL, 40m CAL, etc.
I also did one for HF CAL covering 1-30 MHz with with SAVER I can use thousands of cal points and when I save the file, it is maybe 200 kB.
If your SAVER readings are different from the internal readings, I would first check your CAL files on SAVER.
As mentioned, put the 50 ohm dummy load on and see if the SWR is low (1:1) on each band you test.
2m and 440 MHz has some additional challenges for the leads and adapters.
de k3eui
Just a comment on Calibration - if you are calibrating at the NanoVNA, or with short jumpers, then a single wide band cal is probably sufficient - the interpolation algorithm will find the right values when you're making narrow sweep range measurements. BUT, if you're calibrating at the end of long coax (e.g. measuring an antenna through the feedline), then you might need narrower calibration ranges, or more properly, more closely spaced calibration points.] For example if you have 100 ft of coax (call it 30 meters) equivalent free space length, the feedline puts dips and peaks into the reflection values that are spaced every 5 MHz. A 0-500 MHz sweep with 100 points only measures every 5 MHz, so the interpolation won't necessarily return the right values. As Barry comments, with NanoVNA Saver (and other tools) you can do a thousand or more points in your cal, so then it works ok.
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Re: Different SWR readouts between NanoVNA-H and NanoVNA Saver
Steven
Did you do a CALIBRATION for each band, over a fairly narrow frequency range?
I do that, and SAVE the file: 80m CAL, 40m CAL, etc.
I also did one for HF CAL covering 1-30 MHz with with SAVER I can use thousands of cal points and when I save the file, it is maybe 200 kB.
If your SAVER readings are different from the internal readings, I would first check your CAL files on SAVER.
As mentioned, put the 50 ohm dummy load on and see if the SWR is low (1:1) on each band you test.
2m and 440 MHz has some additional challenges for the leads and adapters.
de k3eui
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I am surprised some folk on this group have rubbished Moonraker Antennas.
I know Moonraker HF antennas are used on some Australian Navy ships, so I don't think they are really "Dollar Shop junk."
I don't have any connection with either Moonraker or the the Australian Navy.
So perhaps those with complaints may need to examine their installation practices.
Or contact Moonraker or their dealer for support.
Just my 2c worth.
Cheers...Bob VK2ZRE
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On 3/08/2023 2:33 am, Clyde Spencer wrote: one has to consider the environment, not discussed prior in this thread. If
there were any metal or other electrically conductive material near the
antenna when tested that could be a possible cause for the difference in
measurement data and that which is published.
*Clyde K. Spencer*
On Wed, Aug 2, 2023 at 11:09?AM Jim via groups.io <teotwaki=
[email protected]> wrote:
This antenna is related to what antenna design literature calls a
“产颈肠辞苍颈肠补濒“
- - Biconical antennas have dipole characteristics. The double cone
elements structure contributes to their wider bandwidth. The antenna
becomes more broadband as the cone angle increases. - -
Search on that name for design and results discussions
Jim
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Re: Different SWR readouts between NanoVNA-H and NanoVNA Saver
Wow, Thanks Dave.
I did not realize I could do that. Just like verifying calibration on the Nano without connecting to the computer.
Steven/kc3dow
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Re: Different SWR readouts between NanoVNA-H and NanoVNA Saver
QUOTE: I don't see any way to verify calibration with Saver but what I do is setup the frequencies that I want to check before doing calibration. .......................................................................................................................... You are correct in setting up your frequency span before doing the cal. in Saver. However, it is easy to check cal. once it is run in Saver. Use the same standards you used for cal. and sweep each one at a time. The short should show a short - extreme left of the Smith Chart. The open should show an open - extreme right of the smith Chart. The 50-ohm standard should be bullseye in the center of the Smith Chart. It's that simple. Dave - W?LEV On Wed, Aug 2, 2023 at 7:53?PM Steven KC3DOW via groups.io <treasurebox7762= [email protected]> wrote: Hi Barry,
Not a 'J' pole. It is a Diamond X-50A. My previous antenna was a 'J' pole
but did not reach an area that I needed to reach.
This Diamond does the job but I am trying to train myself to use the
NanoVNA-H and learn Saver when I ran into the problem. I was trying to
check swr to see if it was within specs.
By the way. I did the calibration correctly and by the book and also did
the verification which was successful.
I don't see any way to verify calibration with Saver but what I do is
setup the frequencies that I want to check before doing calibration.
Thanks for your help,
Steven/kc3dow
-- *Dave - W?LEV* -- Dave - W?LEV
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If the antenna is supported by a metal mast, make sure the lower discone elements (those closest to the mast) are connected to the coax OUTER SHIELD, and the top elements to the coax INNER. If the connections are reversed, the mast interferes with the antenna impedance. Regards, Joe L On Tue, Aug 1, 2023 at 12:26 MarcoFI <marcofigroupsio@...> wrote: Hi Team,
I try to measure VSWR of the following antenna:
NanoVNA is calibrated to antenna side of RG58. I had to use N-F/SMA-M +
SMA-F/SMA-F adapters in front of SOL kit, but tried to subtract it with
edelay.
On the product page someone wrote "Swr on 2m is 1.5 to 1.7.1 on 446 it's
1.0.1". I can't seem to get even close, something wrong with me setup. Any
suggestions what am I missing?
Best Regards,
MarcoFI
-- __Joe Leizerowicz 6424 34 Avenue NW, Calgary, AB T3B 1N1 403-604-7791
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Re: Different SWR readouts between NanoVNA-H and NanoVNA Saver
Hi Barry,
Not a 'J' pole. It is a Diamond X-50A. My previous antenna was a 'J' pole but did not reach an area that I needed to reach.
This Diamond does the job but I am trying to train myself to use the NanoVNA-H and learn Saver when I ran into the problem. I was trying to check swr to see if it was within specs.
By the way. I did the calibration correctly and by the book and also did the verification which was successful.
I don't see any way to verify calibration with Saver but what I do is setup the frequencies that I want to check before doing calibration.
Thanks for your help,
Steven/kc3dow
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one has to consider the environment, not discussed prior in this thread. If there were any metal or other electrically conductive material near the antenna when tested that could be a possible cause for the difference in measurement data and that which is published. *Clyde K. Spencer* On Wed, Aug 2, 2023 at 11:09?AM Jim via groups.io <teotwaki= [email protected]> wrote: This antenna is related to what antenna design literature calls a
“产颈肠辞苍颈肠补濒“
- - Biconical antennas have dipole characteristics. The double cone
elements structure contributes to their wider bandwidth. The antenna
becomes more broadband as the cone angle increases. - -
Search on that name for design and results discussions
Jim
|
This antenna is related to what antenna design literature calls a “产颈肠辞苍颈肠补濒“
- - Biconical antennas have dipole characteristics. The double cone elements structure contributes to their wider bandwidth. The antenna becomes more broadband as the cone angle increases. - -
Search on that name for design and results discussions
Jim
|
Fully configured tinyPFA for sale at Eleshop.
--
For more info on the tinyPFA go to
Erik, PD0EK
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Thanks for your comments. I bought the antenna from local radio store that has a good reputation and it's a shame if they sell crap as it's starting to look like.
I tried to model the antenna in 4nec2 and its output curve looks a bit similar to NanoVNA measurement. NanoVNA shows higher SWR though, not sure why?
Based on both results it seems that this antenna could not be used for TX at least not in the advertised lower 130-175 MHz range and therefor I think I own 16 pieces of nice stainless steel skewers.
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Re: Different SWR readouts between NanoVNA-H and NanoVNA Saver
Oh…. I just saw you said a VHF antenna.
I’m going to guess —-
Any chance this VHF antenna is a J-Pole?
If so, when measuring SWR with your Nano VNA, rub your hand up/down the coax near the VNA jack and see if the SWR changes as you move your hand over a 1 meter length.
If the SWR changes, we know the problem.
Current on the outside of the coax.
barry
k3eui
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Take a look at the published gain specifications by MoonRacker of their CB
antennas. You'll rapidly convince yourself anything MoonRacker publishes
for their antennas is total rubbish. They are not a reputable supplier for
the amateur radio world, RX only and/or RX/TX.
Dave - W?LEV
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On Tue, Aug 1, 2023 at 6:26?PM MarcoFI <marcofigroupsio@...> wrote: Hi Team,
I try to measure VSWR of the following antenna:
NanoVNA is calibrated to antenna side of RG58. I had to use N-F/SMA-M +
SMA-F/SMA-F adapters in front of SOL kit, but tried to subtract it with
edelay.
On the product page someone wrote "Swr on 2m is 1.5 to 1.7.1 on 446 it's
1.0.1". I can't seem to get even close, something wrong with me setup. Any
suggestions what am I missing?
Best Regards,
MarcoFI
-- *Dave - W?LEV*
--
Dave - W?LEV
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You might be missing the fact that the antenna isn't what it is cracked up to be. Your SWR "someone wrote" is malarki... There isn't any manufacture data (not that I would believe it if there was...)
So... depending how it is wired it may just in fact be a simple dipole rather than a discone...
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Hi Team,
I try to measure VSWR of the following antenna:
NanoVNA is calibrated to antenna side of RG58. I had to use N-F/SMA-M + SMA-F/SMA-F adapters in front of SOL kit, but tried to subtract it with edelay.
On the product page someone wrote "Swr on 2m is 1.5 to 1.7.1 on 446 it's 1.0.1". I can't seem to get even close, something wrong with me setup. Any suggestions what am I missing?
Best Regards,
MarcoFI
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Re: Different SWR readouts between NanoVNA-H and NanoVNA Saver
That is very odd indeed, Steven.
Try this:
Connect a 50 ohm dummy load and do an SWR sweep when Nano VNA is not on SAVER.
Take a look at SWR, reflection coefficient, return loss, and Smith Chart.
Then do the same tests with the same dummy load with Nano VNA SAVER software running.
The graphs should be identical
If not, I suspect a “calibration” error when you were doing the Nano SAVE calibrations.
If they are identical with a dummy load - then there is no problem with SAVER.
Then I would check the coax for something “odd”.
Let us know if the dummy load produces a SWR of 1:1 across the band you are testing.
BTW - what antenna ? and what frequencies?
If this is your “end fed” then I would look for RFI leaking back on the outside shield of the coax.
That is often an issue with “end-fed, one-half wave” 130 ft wires with a 49:1 UNUN.
Put some kind of “choke” in the feed line.
The outside shield may be acting like your “counterpoise” inadvertently.
give me a call when you figure it out
k3euibarry@...
barry
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Re: color of correct load, short, and open caps
Thanks everyone, that worked.
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Re: Measuring the SRF of a capacitor ?
You may find these two videos from W0QE interesting:
He discusses three different methods to test components, and why you might want to use each one for components of various values. I used to use his fixturing methods well above the frequencies at which you will be testing doorknob capacitors.
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Hi David, I just checked the gitHub site, and the latest version 0.6.1, as of ~10 hours ago, only has three assets listed for the latest revision all of which appear to be Linux-based. However, if you scroll down the page a bit to the previous version, Version 0.5.5, under the 05-March block titled ‘Core is spinning’, and go down to the bottom of that block, you should see the word “Assets” just below the ‘Contributors’ section. Click on “Assets”, and that should open another listing from which you can download either the 32-bit or 64-bit Windows executables for Version 0.5.5. With any luck, someone will compile the Windows executables for the latest Version 0.6.1. Good luck. 73 Ken -- WB?OCV From: Paul Braun Sent: Monday, July 31, 2023 06:02 PM To: [email protected]Subject: Re: [nanovna-users] releases Hmm. There are notes about the Windows version having issues and they were also wondering if Windows is no longer supported. Paul Braun WD9GCO Anchor, Amateur Radio Newsline Certified Music Junkie "Never follow anyone. Be your own hero." -- Neil Peart
"Music washes from the soul the dust of everyday life." -- Berthold Auerbach
"The Fountain of Youth is a state of mind" -- The Ides of March, "Age Before Beauty"
"Deep inside we're all the same." -- Dennis DeYoung/Styx On Jul 31, 2023, at 16:41, David Rodriguez Martin <dr8297@...> wrote:
?Hi Team,
I have been trying to download a windows installer from . The windows installer have been changed to text rather than links and I am wondering if the nanovna has stopped supporting the windows release.
David, M0KGE
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Barry K3EUI
Dentron
Jim Allyn - N7JA