I'm going mad trying to get Saver to load and run.
NanoVNA-F V2
Rev. C
Firmware v0.3.0
Build Aug 2021
Windows 10 - up to date. Running as Administrator
NanoVNASaver.x64
v0.4.0
I download, extract, run as administrator. Black window appears, fills with text, then closes, and then nothing (I've waited an hour!)
No doubt something I'm doing wrong, but what?!
David, G4YTL
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Re: Smith's book. free download
All, these sources of ¡°free books¡± most likely contain some current copyrighted material and despite a USA string in the URL are more likely Chinese or other offshore based entities. Just know what you are doing.
Oh and here¡¯s a quote from PCMag: ¡° PC Matic does install an ad blocker in your browsers, but there's no component to detect and avert malware-hosting URLs or phishing URLs¡±.
Just saying ...
Dan
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Re: At which point do we take the value of impedance to tune an antenna?
A lot of good discussion here, but I would like to answer the original question from Diane BONKOUNGOU: In my opinion you are not ready to match the antenna. You should bring the antenna to resonance at your desired frequency by shortening it to resonance first, then consider if the SWR is low enough to be finished or you need to match it. Be sure to measure the resonance with the antenna and the mounting the same as it will be in the finished product, metal parts and circuit boards will change the resonance if they change. Circuit board layout is critical at these frequencies. Be sure you have followed the chip manufacturer's layout recommendations EXACTLY in the RF areas of the circuit board, including trace widths and type of components used. Don't use zero ohm resistors as jumpers or to select a test connector versus the antenna circuit, since they are inductive at these frequencies, use SMD capacitors that are self resonant at your operating frequency. What SWR is low enough? Minimum 10 dB return loss or SWR = 2 or less was the value we used for consumer Wi-Fi and Bluetooth at the multi billion dollar company that I worked for. Trying to get it lower would usually lead to losses in the matching components wasting more power than was gained in signal strength.
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Re: At which point do we take the value of impedance to tune an antenna?
Hi, Jerry,
You're right that the lowest SWR may not occur at resonance, whichever definition of
resonance you use. For a particular combination of antenna and transmission line, 1:1
may not be possible as the resistance of the line may not pass through 50 ohms at
the same frequency where the reactance passes through zero ohms.
This may not matter much, if at all, in most cases. If you calculate what happens if you
don't achieve 1:1, but must settle for something "worse," the difference may not be
discernible during actual transmissions.
73,
Maynard
W6PAP
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On Monday, August 08, 2022 06:00:25 PM Jerry Stuckle wrote: Maynard,
True in this particular case. I was just trying to simplify matters. I
guess I didn't do so well.
My point is that the lowest SWR is NOT necessarily the resonant point.
In fact, very few antennas have an impedance of 50 ohms at resonance.
The lowest SWR may be above or below the resonant frequency.
On 8/3/2022 11:06 AM, Maynard Wright, P. E., W6PAP wrote:
SWR = Zt / Zo applies only when both impedances are resistive. When Zt =
40 + j30 ohms, the load is highly reactive. The coefficient of
reflection rho is:
rho = (Zt - Zo) / (Zt + Zo) = 0 + j0.3333 ...
SWR = (1 + abs(rho)) / (1 - abs(rho)) = 2.0
73,
Maynard
W6PAP
On Tuesday, August 02, 2022 05:26:38 PM Jerry Stuckle wrote:
Incorrect. The VSWR is based on impedance - which is a combination of
resistance and reactance. A vertical at resonance will have an impedance
of about 35 + 0j ohms or an impedance of 35 ohms and a 50/35 or 1.43:1
SWR.
However, slightly off resonance it could have an impedance of say 40 +
30j
ohms, which would have a total impedance of 50 ohms (just an example for
ease of calculations) and an SWR of 1:1. The antenna is non-resonant at
the lowest SWR reading. -----------------------------------------
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Re: At which point do we take the value of impedance to tune an antenna?
Maynard,
True in this particular case. I was just trying to simplify matters. I guess I didn't do so well.
My point is that the lowest SWR is NOT necessarily the resonant point. In fact, very few antennas have an impedance of 50 ohms at resonance. The lowest SWR may be above or below the resonant frequency.
toggle quoted message
Show quoted text
On 8/3/2022 11:06 AM, Maynard Wright, P. E., W6PAP wrote: SWR = Zt / Zo applies only when both impedances are resistive. When Zt = 40 +
j30 ohms, the load is highly reactive. The coefficient of reflection rho is:
rho = (Zt - Zo) / (Zt + Zo) = 0 + j0.3333 ...
SWR = (1 + abs(rho)) / (1 - abs(rho)) = 2.0
73,
Maynard
W6PAP
On Tuesday, August 02, 2022 05:26:38 PM Jerry Stuckle wrote:
Incorrect. The VSWR is based on impedance - which is a combination of
resistance and reactance. A vertical at resonance will have an impedance
of about 35 + 0j ohms or an impedance of 35 ohms and a 50/35 or 1.43:1 SWR.
However, slightly off resonance it could have an impedance of say 40 + 30j
ohms, which would have a total impedance of 50 ohms (just an example for
ease of calculations) and an SWR of 1:1. The antenna is non-resonant at
the lowest SWR reading.
-----------------------------------------
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Re: At which point do we take the value of impedance to tune an antenna?
VSWR is measured in voltage but the cause is the difference in impedance (if there is one) between two items - in this case the feedline and the antenna.
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Re: At which point do we take the value of impedance to tune an antenna?
First of all, there is no SWR of 1:2. SWR is always X:1.
And a 50 ohm cable feeding a 50 ohm load is by definition an SWR of 1:1.
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Re: Smith's book. free download
For those that don't like strange download sites, the book is now on archive.org
Give the page a couple of hours to populate all the options. The pdf is available now, in browser read later.
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Re: Modify Original Nanovna for easy DFU mode like the H4
#dfu
#mods
On Wed, Jan 22, 2020 at 03:03 PM, Larry Rothman wrote: - Change R5 to 1K ohm (same as H4) One remark regarding the -H versions: If you look at Hugen's schematics, you will see that R5 has the same value of 1 kOhm as for the -H4 version. Therefore Larry's modification can be simplified. No need to change R5, just add one wire from P1/BOOT0 to the centre pin of the jog switch and you are on the very safe side regarding the HI potential.
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Re: Smith's book. free download
I have a collection of maybe a dozen Smith Chart variations that I keep as masters to make copies/scans as needed.
73, Don N2VGU
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Re: Smith's book. free download
One alternative that I use is the software, 3D Smith Chart: 3dsmithchart.com. Inexpensive. No color crayons necessary, ?
Frank
K4FMH
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Re: Smith's book. free download
Justin,
If you follow these things enough, sometimes with the more difficult to understand first, make the later simpler explanations just pop out at you and make sense. There is no wasted perusing of all this stuff we have access to. Keep perusing on¡..
Dave K8WPE
David J. Wilcox¡¯s iPad
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On Aug 7, 2022, at 11:55 AM, Justin Bowser - KI5GKD <justin.bowser@...> wrote:
?TNX, just downloaded it. Pretty hefty PDF @ 21 MB!
Not sure I'll understand anything in it... :-\
73,
Justin B.
KI5GKD
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Re: How find crystal filter terminaison resistor and capacitor
Hi again, and basic principle of the output impedance measurement. [image: image.png] Step 1. measure outpunt voltage V1 with no load (open circuit) Step 2 terminate ouput with the known resistor Step 3 Calculate Zout / Rout [image: image.png] 73 Predrag , 9a3qv On Mon, 8 Aug 2022 at 11:26, Predrag Pavo?evi? via groups.io <ppavosevic= [email protected]> wrote: Hi all,
this might be helpful.
[image: image.png]
[image: image.png]
R should be ~ 1 - 2 kOhm, noniductive.
73
Predrag, 9A3QV
On Mon, 8 Aug 2022 at 10:37, Arie Kleingeld PA3A <pa3a@...> wrote:
Thanks for this comment Gerard.
I upgraded to from DiSlord 1.1 to DiSlord 1.2.00 on an H4.3 and it seems
to work.
I tried 300 ohm as Zo and it moved the 50 ohm load to the place it
should be on a 300 ohm Smith Chart.
So far so good.
73
Arie PA3A
Op 8-8-2022 om 03:40 schreef John Gord via groups.io:
Gerard,
It looks like the latest H and H4 firmware from DiSlord also has the Port-Z rescaling.
--John Gord
On Sun, Aug 7, 2022 at 11:34 AM, John Gord wrote:
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Re: How find crystal filter terminaison resistor and capacitor
Hi all,
this might be helpful.
[image: image.png]
[image: image.png]
R should be ~ 1 - 2 kOhm, noniductive.
73
Predrag, 9A3QV
toggle quoted message
Show quoted text
On Mon, 8 Aug 2022 at 10:37, Arie Kleingeld PA3A <pa3a@...> wrote: Thanks for this comment Gerard.
I upgraded to from DiSlord 1.1 to DiSlord 1.2.00 on an H4.3 and it seems
to work.
I tried 300 ohm as Zo and it moved the 50 ohm load to the place it
should be on a 300 ohm Smith Chart.
So far so good.
73
Arie PA3A
Op 8-8-2022 om 03:40 schreef John Gord via groups.io:
Gerard,
It looks like the latest H and H4 firmware from DiSlord also has the Port-Z rescaling.
--John Gord
On Sun, Aug 7, 2022 at 11:34 AM, John Gord wrote:
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Re: How find crystal filter terminaison resistor and capacitor
Thanks for this comment Gerard.
I upgraded to from DiSlord 1.1 to DiSlord 1.2.00 on an H4.3 and it seems to work.
I tried 300 ohm as Zo and it moved the 50 ohm load to the place it should be on a 300 ohm Smith Chart.
So far so good.
73
Arie PA3A
Op 8-8-2022 om 03:40 schreef John Gord via groups.io:
toggle quoted message
Show quoted text
Gerard,
It looks like the latest H and H4 firmware from DiSlord also has the Port-Z rescaling.
--John Gord
On Sun, Aug 7, 2022 at 11:34 AM, John Gord wrote:
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Re: How find crystal filter terminaison resistor and capacitor
Gerard,
It looks like the latest H and H4 firmware from DiSlord also has the Port-Z rescaling.
--John Gord
toggle quoted message
Show quoted text
On Sun, Aug 7, 2022 at 11:34 AM, John Gord wrote:
Gerard,
In addition to the variable resistance fixture method, there is provision in
some firmware versions to mathematically modify the displayed data to show
what the response would be in a system with Z0 other than 50 ohms.
I think that this feature is available only for the V2 and later versions
because of the memory limitations in the original NanoVNA.
You can set Z0 to say, 330 ohms for typical 10.7 MHz ceramic filters. I don't
know how well this would work at 4kohm.
The DiSlord firmware has the Port-Z setting in the DISPLAY menu. The
ojisankoubou firmware has the Port-Z setting in the DISPLAY/SIMULATE menu.
--John Gord
On Sun, Aug 7, 2022 at 03:04 AM, Gerard wrote:
Hello,
I have a lot of 2 poles filters 20J26 Motorola and 45R15AZ.
I can¡¯t find the datasheet of these filters on the net, except on a site
that tells me that the 45R15AZ is a 3rd harmonic filter, but no datasheet.
So I have no value of termination resistance and capacity.
In addition, if you take a common model like a 45M15A, you find different
values depending on the manufacturer, it ranges from 560 Ohm/1pf to 4KOhm
-1pf.
My question is whether we can measure these values with a nanovna or some
other method.
and if you have the datasheet, put it.
Thank you
|
Re: How find crystal filter terminaison resistor and capacitor
Gerard,
In addition to the variable resistance fixture method, there is provision in some firmware versions to mathematically modify the displayed data to show what the response would be in a system with Z0 other than 50 ohms.
I think that this feature is available only for the V2 and later versions because of the memory limitations in the original NanoVNA.
You can set Z0 to say, 330 ohms for typical 10.7 MHz ceramic filters. I don't know how well this would work at 4kohm.
The DiSlord firmware has the Port-Z setting in the DISPLAY menu. The ojisankoubou firmware has the Port-Z setting in the DISPLAY/SIMULATE menu.
--John Gord
toggle quoted message
Show quoted text
On Sun, Aug 7, 2022 at 03:04 AM, Gerard wrote:
Hello,
I have a lot of 2 poles filters 20J26 Motorola and 45R15AZ.
I can¡¯t find the datasheet of these filters on the net, except on a site
that tells me that the 45R15AZ is a 3rd harmonic filter, but no datasheet.
So I have no value of termination resistance and capacity.
In addition, if you take a common model like a 45M15A, you find different
values depending on the manufacturer, it ranges from 560 Ohm/1pf to 4KOhm
-1pf.
My question is whether we can measure these values with a nanovna or some
other method.
and if you have the datasheet, put it.
Thank you
|
Re: Smith's book. free download
You can create your own by printing or phocopying a blank chart onto A4 transparency film.- Michael (GW7BBY)
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On 06/08/2022 21:46, alan victor wrote: That book text site has a GOLDMINE of super books. Thanks for the link!
The Smith applications text comes with a dozen or so plastic overlays that are used in the text as a means of solving designs. You use a grease pencil.
Almost as munch fun as fooling with the vna. I have the originals and some where I stored away some clear plastic copies that I used in analog powerpoint
presentations!
Alan
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Re: Smith's book. free download
Interesting! I use PCmatic anti-virus and it's perfectly happy with that site?? Rudy N6LF
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Re: Smith's book. free download
Oops, 27 MB!
73,
Justin B.
KI5GKD
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Ho-Ro
Donald S Brant Jr
Frank K4FMH
David Wilcox K8WPE
Arie Kleingeld PA3A