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Re: New owner of nanovna-H and H4, However pondering the next step in precision

 

I am happy with my LibreVNA, but I also bought a better calibration kit than was provided. The quality of the kit and accuracy of the standards' characterization will directly affect the accuracy of the results. I use it in my professional practice, most recently to characterize a MIL SATCOM IF processing unit I designed for a client for a client. Jan's software support is excellent and he is making ongoing improvements.
73, Don N2VGU
Re: New owner of nanovna-H and H4, However pondering the next step in precision

 

Oroot,
At frequencies up to 1GHz or so, it is certainly practical to make your own Open, Short, and Load. Ideally, the three standards should be the same length, which becomes more critical at higher frequencies because the wavelength gets shorter.
Search for something like "homemade 50 ohm load vna" to get some ideas on what others have done.
The QEX article is available online to ARRL members. Perhaps a nearby friend who is a member could print the article for you. Failing that, the author of the article is Gary Cobb, and his email is g3tmg@.... He might be willing to email you a copy of the article. The title is "Improved Low-loss Measurements with a NanoVNA".
--John Gord

On Wed, Aug 3, 2022 at 06:32 PM, 0root wrote:


Hi John

Good guess at both my range of interest(indeed below 900MHz) and the education
side... I have very limited techniques as im new to it all.

Im going to try and find that article you mention, if not il try to buy an old
hard copy of the mag on ebay.

Re the loads, you are referring to the three calibration connectors provided
correct?
Would making my own finer tuned ones be a realistic task? as in components,
pricing, and skill?
If not if you know anywhere to buy some finer tuned I would appreciate the
link

Thanks for the help!
Re: New owner of nanovna-H and H4, However pondering the next step in precision

 

Correction
Between 1400 and 4000
But that one goes to 20 gig hz!!!


Greetz sigi dg9bfc

Am 04.08.2022 06:30 schrieb Siegfried Jackstien <siegfried.jackstien@...>:




KC901
Different range (and so price) available
Between 1000 and 2000 bucks or so
Much more professional and accurate as all the Nanos... And still portable
use (with a bit bigger display)
So i recommend those if you really want to spent more for a better unit
Dg9bfc sigi



Am 04.08.2022 03:32 schrieb "0root via groups.io"
<hntpro@...>:






Hi John

Good guess at both my range of interest(indeed below 900MHz) and the
education side... I have very limited techniques as im new to it all.

Im going to try and find that article you mention, if not il try to buy
an
old hard copy of the mag on ebay.

Re the loads, you are referring to the three calibration connectors
provided correct?
Would making my own finer tuned ones be a realistic task? as in
components, pricing, and skill?
If not if you know anywhere to buy some finer tuned I would appreciate
the
link

Thanks for the help!
Re: New owner of nanovna-H and H4, However pondering the next step in precision

 

KC901
Different range (and so price) available
Between 1000 and 2000 bucks or so
Much more professional and accurate as all the Nanos... And still portable use (with a bit bigger display)
So i recommend those if you really want to spent more for a better unit
Dg9bfc sigi

Am 04.08.2022 03:32 schrieb "0root via groups.io" <hntpro@...>:




Hi John

Good guess at both my range of interest(indeed below 900MHz) and the
education side... I have very limited techniques as im new to it all.

Im going to try and find that article you mention, if not il try to buy an
old hard copy of the mag on ebay.

Re the loads, you are referring to the three calibration connectors
provided correct?
Would making my own finer tuned ones be a realistic task? as in
components, pricing, and skill?
If not if you know anywhere to buy some finer tuned I would appreciate the
link

Thanks for the help!
Re: Launch of a new product by Deepelec (DeepSDR 101)!

 

Hello,
I did a surch the project,
:
DeepSDR Radio DSP Digital Demodulation Shortwave AM FM MW SSB CW HAM Receiver

Clyde KC7BJE
Re: At which point do we take the value of impedance to tune an antenna?

 

On both charts, 25+j0 and 100+j0 need to be swapped. They are wrong as labeled.

On Wednesday, August 3, 2022, 06:42:32 PM EDT, Roger Need via groups.io <sailtamarack@...> wrote:

Time is well spent learning a bit about the Smith Chart.

You can plot a complex? impedance and then draw a circle that intersects the point and get the SWR.? You can also measure the distance and get the reflection coefficient and gamma.

A picture is worth a thousand words so here is a plot on a Smith Chart of several complex impedances that all result in a SWR of 2 and a reflection coefficient of 0.333 ( a Reflection Loss of 9.54 dB).? The 40 + j30 from the earlier discussion is one of these.

Roger
Re: Launch of a new product by Deepelec (DeepSDR 101)!

 

Kadir, what does it offer that nanovna-h doesnt?
Re: New owner of nanovna-H and H4, However pondering the next step in precision

 

Hi John

Good guess at both my range of interest(indeed below 900MHz) and the education side... I have very limited techniques as im new to it all.

Im going to try and find that article you mention, if not il try to buy an old hard copy of the mag on ebay.

Re the loads, you are referring to the three calibration connectors provided correct?
Would making my own finer tuned ones be a realistic task? as in components, pricing, and skill?
If not if you know anywhere to buy some finer tuned I would appreciate the link

Thanks for the help!
Re: Launch of a new product by Deepelec (DeepSDR 101)!

Doug
 

I, for one, really appreciated hearing about this new product although it may have been in the wrong forum.

I don't know where else Kadir might have announced it that I would have seen it. Perhaps there is an SDR forum for such news.

Doug.

On 03/08/2022 21:13, Kadir Mari?o Abreu wrote:
I apologize for the inconvenience caused, it will not be repeated, thank you.



--
*/If you forward this email, please delete the forwarding history which also includes my email address. When sending emails, please BCC so as to hide all addresses. Thanks for helping to prevent Scammers and Spammers from mining addresses and spreading viruses./

73

Doug Kearney VA3DKA

*

*Ottawa, ON *
--
This email has been checked for viruses by Avast antivirus software.
Re: Launch of a new product by Deepelec (DeepSDR 101)!

 

I apologize for the inconvenience caused, it will not be repeated, thank you.
Re: New owner of nanovna-H and H4, However pondering the next step in precision

 

Oroot,
Assuming the frequency range of interest is 900MHz and below, your best investment for better accuracy in RL/VSWR and attenuation is probably educating yourself in best technique.
As an example, the recent QEX magazine (July/Aug 2022) has an article on using the NanoVNA to accurately measure low loss devices like short cables and RF relays.
Another investment might be in a better Load standard for the connector type you use most. The supplied standard load is fine for most purposes, but for measuring very high RL the NanoVNA is capable of taking advantage of a better load. You can probably make your own Short and Open for any connector type you use at HF/VHF/UHF frequencies.
--John Gord

On Wed, Aug 3, 2022 at 04:55 PM, 0root wrote:


Hey all, first post here.

I currently own and love the nanovna-h and h4, I was sure to buy them from the
alibaba store zeenko as this is apparantly hugens chosen manufacturer.

However, if I wanted to get more precision - specifically in the areas of
Return Loss / VSWR and attenuation readings - what would be the next device up
to get - within the region of $100 - $2000 and no higher...

I see alot of siglent stuff, but the reviews are not too appetizing

Re: At which point do we take the value of impedance to tune an antenna?

 

An excellent learning tool by just jumping in is SimSmith:



There is also an excellent tutorial (and a lot more) by W?QE at:



Dave - W?LEV

On Wed, Aug 3, 2022 at 10:42 PM Roger Need via groups.io <sailtamarack=
[email protected]> wrote:

Time is well spent learning a bit about the Smith Chart.

You can plot a complex impedance and then draw a circle that intersects
the point and get the SWR. You can also measure the distance and get the
reflection coefficient and gamma.

A picture is worth a thousand words so here is a plot on a Smith Chart of
several complex impedances that all result in a SWR of 2 and a reflection
coefficient of 0.333 ( a Reflection Loss of 9.54 dB). The 40 + j30 from
the earlier discussion is one of these.

Roger





--
*Dave - W?LEV*
*Just Let Darwin Work*


--
Dave - W?LEV
New owner of nanovna-H and H4, However pondering the next step in precision

 

Hey all, first post here.

I currently own and love the nanovna-h and h4, I was sure to buy them from the alibaba store zeenko as this is apparantly hugens chosen manufacturer.

However, if I wanted to get more precision - specifically in the areas of Return Loss / VSWR and attenuation readings - what would be the next device up to get - within the region of $100 - $2000 and no higher...

I see alot of siglent stuff, but the reviews are not too appetizing
Re: At which point do we take the value of impedance to tune an antenna?

 

Time is well spent learning a bit about the Smith Chart.

You can plot a complex impedance and then draw a circle that intersects the point and get the SWR. You can also measure the distance and get the reflection coefficient and gamma.

A picture is worth a thousand words so here is a plot on a Smith Chart of several complex impedances that all result in a SWR of 2 and a reflection coefficient of 0.333 ( a Reflection Loss of 9.54 dB). The 40 + j30 from the earlier discussion is one of these.

Roger

Smith Chart 2.0.png
Smith Chart 2.0 zoom.png

Re: Launch of a new product by Deepelec (DeepSDR 101)!

 

As long as it is free and open source, I don't mind the announcements for related projects.
If it is a product you have to pay for, I am all for every bit of censorship.

On Wednesday, August 3, 2022, 03:48:35 PM EDT, Dave Daniel <kc0wjn@...> wrote:

Kadir,

Please do not post messages on this forum that contain only marketing information that is not specifically related to the NanoVNA product concerned with this particular group.

I have deleted the message.

DaveD, co-owner

On Aug 3, 2022, at 14:55, Kadir Mari?o Abreu <cm3kma@...> wrote:

?New product release !
DeepSDR 101 Software Defined Radio DSP Digital Demodulation Shortwave CW SSB AM FM Broadcast Receiver
Re: Launch of a new product by Deepelec (DeepSDR 101)!

 

Kadir,

Please do not post messages on this forum that contain only marketing information that is not specifically related to the NanoVNA product concerned with this particular group.

I have deleted the message.

DaveD, co-owner

On Aug 3, 2022, at 14:55, Kadir Mari?o Abreu <cm3kma@...> wrote:

?New product release !
DeepSDR 101 Software Defined Radio DSP Digital Demodulation Shortwave CW SSB AM FM Broadcast Receiver
Re: At which point do we take the value of impedance to tune an antenna?

 

Yes!!! Learn the Smith Chart!!!! Also, learn and internalize Ohm's
Law!!!! Both will serve you well with all things RF.

SWR can be measured as current, or voltage standing wave ratios.

A good test for all this confusion is to establish a system which measures
1:1 SWR at a known frequency. Then add an electrical 1/8 to 1/4-wavelength
of transmission line to the system. If the SWR remains 1:1 with the added
transmission line in place, indeed, the SWR is 1:1. If the measurement
with the additional line length measures something other than 1:1, the
original 1:1 measurement is in error. This is the primary reason
S-parameters deal strictly with power, the product of voltage and current
for a sine wave. With SWR on the transmission line, voltage and current
along the line changes as measured at single points along the line.
However, power remains the same along the line - it's just Ohm's law with a
little very simple algebra.

Dave - W?LEV

On Wed, Aug 3, 2022 at 4:10 PM Kenneth Hendrickson via groups.io <dsp_stap=
[email protected]> wrote:

Russ,

If the load is not perfectly matched to the source, there will be a
voltage standing wave ratio (VSWR) because of the mismatch.

Learn the Smith chart.

On Wednesday, August 3, 2022, 11:52:31 AM EDT, Russ <
u.rusty@...> wrote:

On Tue, Aug 2, 2022 at 05:26 PM, Jerry Stuckle wrote:


The VSWR is based on impedance - which is a combination of resistance and
reactance.
Can you explain this in more detail. I thought VSWR was based on voltage.











--
*Dave - W?LEV*
*Just Let Darwin Work*


--
Dave - W?LEV
Re: At which point do we take the value of impedance to tune an antenna?

 

Helpful document:

On 8/3/2022 9:10 AM, Kenneth Hendrickson via groups.io wrote:
Russ,

If the load is not perfectly matched to the source, there will be a voltage standing wave ratio (VSWR) because of the mismatch.

Learn the Smith chart.

On Wednesday, August 3, 2022, 11:52:31 AM EDT, Russ <u.rusty@...> wrote:
On Tue, Aug? 2, 2022 at 05:26 PM, Jerry Stuckle wrote:

The VSWR is based on impedance - which is a combination of resistance and
reactance.
Can you explain this in more detail. I thought VSWR was based on voltage.
Re: At which point do we take the value of impedance to tune an antenna?

 

Russ,

If the load is not perfectly matched to the source, there will be a voltage standing wave ratio (VSWR) because of the mismatch.

Learn the Smith chart.

On Wednesday, August 3, 2022, 11:52:31 AM EDT, Russ <u.rusty@...> wrote:

On Tue, Aug? 2, 2022 at 05:26 PM, Jerry Stuckle wrote:


The VSWR is based on impedance - which is a combination of resistance and
reactance.
Can you explain this in more detail. I thought VSWR was based on voltage.
Re: At which point do we take the value of impedance to tune an antenna?

 

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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