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Re: NanoVNA vs. MFJ-259B Antenna Analyzer

 

Dave:
What program do you favkr for the interconnect
Thanks.

Ed McCann
AG6CX
Re: Writing nanovna results to csv file #nanovna-saver

 

On 9/13/20 5:23 PM, WB2UAQ wrote:
I have been saving s1p and s2p files from Saver and then re-save them as .txt files. In Excel I import external data in the .txt format and delimit using spaces. This works well for using S21 Thru and S21 Shunt methods for calculating low impedances and high impedances. Having a great time with this little NanoVNA. BTW, when I was involved with hp network analyzers never heard the term VNA for them as it was assumed they could measure the amplitude and phase. They were referred to as network analyzers. Or scaler network analyzers for those that could not determine phase relationships (they used diode detectors only).
\
Well, Keysight (nee Agilent, nee HP) also has PNAs and XNAs these days, too <grin>

There are VNAs that use only diode detectors (look up 6-port analyzer) - they work sort of like the 3 meter technique for measuring impedance.


For what it's worth, there are libraries in Python to read "touchstone" files (i.e. s1p, s2p, etc.).




scikit-rf (aka skrf) is an Open Source, BSD-licensed package for RF/Microwave engineering implemented in the Python programming language. It provides a modern, object-oriented library which is both flexible and scalable. The documentation below is broken up into three sections; narrative tutorials, practical examples, and a reference API.


Does Smith Charts, complex plane, and various and sundry variable vs frequency plots.

And it can do transformations among types of networks (S,T, Y, Z, etc.)


It also does VNA calibration (12 term, 8 term, etc.) and things like arbitrary N-ports, cascades, and de-embedding.
Re: NanoVNA vs. MFJ-259B Antenna Analyzer

 

R&L electronics - bought on recommendations of people here. It worked
right out of the box (nicely packaged) within one week of purchase. I
bought on sale and got the 4" version.

Have tuned my 6M yagi after rebuilding it, am working on 2m yagi (also
rebuilding).

No issues at all.

Scott aka kb0fhp

On Sun, Sep 13, 2020, 20:23 K5TRP <trippsanders99@...> wrote:

R and L electronics at Randl.com is an authorized dealer in the us.

On Sun, Sep 13, 2020 at 7:14 PM Brandon Parker <bmanthug@...> wrote:

Sorry but that's not the case man. Don't get me wrong it's useful. But my

ability to understand it' is not the issue. My issues with it are the
lack

of morals by the people that sold it. I have a certain disgust with the

whole idea of it because the bad luck I've had buying them. And the lack
of

support from the crooked sellers. If I have to worry that bad about
whether

I'm gonna get a functional unit or not... "so far two out of two were
junk"

I managed to repair one of them and I use it for building transistor

circuits. So again I know how to use it. But to say it does more that's
not

true. It doesn't do the fault finding in coax the same. That alone is a

feature I'd gladly pay for. And I just prefer the ruggedness of the mfj.

I'm sure with time I'll revisit it. And I'm gonna ask folks on here about

where the right place to buy it is as in who are the reputable sellers. I

think I may have just been getting out some frstration with the
situation.

I guess I bought the mfj because I KNOW it will work and it will come
with

the correct parts. The situation with the nano vna actually caused me

problems with not getting a larger amplifier out on time. And the mfj
makes

it so easy to tune output coils. It generates all the info I need to do
my

job where as the nano vna is all kinds of little screen and if you have

sausage fingers you gotta use the little stylus thjng. Or hook it to the

computer. I figure for that part the mfj is worth what I spent on it. All

frustration aside I will be looking around a little before I buy another

nano vna. Matter of fact.... What's the larger better ones if anyone

doesn't mind... I actually would grab one but I'd like to know where I

should purchase it from so I have better experience with it this time.
Like

do you guys get em on ebay or is there some other outlet to buy them
from?



On Sun, Sep 13, 2020, 7:44 PM David Eckhardt <davearea51a@...>
wrote:



Sorry you had that experience. Likely, you did not take the time to
learn

how to use the NANOVNA!! It is a *FAR* more capable instrument than
anything MFJ offers at 4X the price, but it is not just an antenna
analyzer

which the MFJ product is. The NANOVNA's are not great just for the
price,

but for what they offer the user - IF, and only IF the user is willing
to

learn how to use the instrument. It's no toy!!!!!!!
Dave - W?LEV
On Sun, Sep 13, 2020 at 11:38 PM Brandon Parker <bmanthug@...>
wrote:
I own a Mano vna and I threw it in the toolbox and just paid the 360
bucks
for the mfj with the wall wart without hesitation. Nano vna is
junk. I

have had nothing but problems. I've boughten two now and they were
both

junk. The first one the person I bought it from got mad that I had
put

the
wrong address and sent me a returned item that was broken. I gave up
claiming the replacement because the seller was obviously a pos that
hates
life. And tokk their own hatred out on me. When I was just another
paying

customer. I needed it then and there and instead of just sending me a
good
one they told me to send it back and they would replace it. All set.
Next

one had issues too from an entire different seller. Goes to show the
quality you can expect from a stupid 50 dollar pc of test equipment.
Nope

I'll stick with the pros. And the fact is.... The Nano vna is used
for

different things. It's good for circuit analysis. Like for my
amplifiers

and testing my transformers impedance. But as far as big boy Jobs and
measuring inductance on my coils n such and my antenna tuning I'll
stick

with the mfj. People only speak highly of the Nano vna because it's a
cheap
way out to KIND OF do the job. And I've seen soooooo many bad
reviews
of

bad experiences with buying the nano vna. It's hit or miss. You MIGHT
get a
fully functional unit. But your odds of getting screwed with a junk
one....
Are JUST as good. I'll spend the money and get what the PROS use.
Forget

the nano vna
Just a cheap Chinese knock off type TOY
On Wed, Sep 9, 2020, 12:01 PM OneOfEleven <cmoss296@...>
wrote:

I just watched VE3OSO's comparison video and had a chuckled at the
end

lol.
I've been thinking for a while just how peed off MFJ must be now
that

we
have these extremely useful little VNA's, especially with how much
they

cost. MFJ's sales must have taken a hit I should imagine.
--
*Dave - W?LEV*
*Just Let Darwin Work*






--
73,
Tripp Sanders
K5TRP
Re: NanoVNA vs. MFJ-259B Antenna Analyzer

Brandon Parker
 

OK cool ty for the reply I'll check it out. Now that I've got that out of
my system... Lol I still have plenty of reasons to have both so I do want
to get a good functional nano vna

On Sun, Sep 13, 2020, 8:23 PM K5TRP <trippsanders99@...> wrote:

R and L electronics at Randl.com is an authorized dealer in the us.

On Sun, Sep 13, 2020 at 7:14 PM Brandon Parker <bmanthug@...> wrote:

Sorry but that's not the case man. Don't get me wrong it's useful. But my

ability to understand it' is not the issue. My issues with it are the
lack

of morals by the people that sold it. I have a certain disgust with the

whole idea of it because the bad luck I've had buying them. And the lack
of

support from the crooked sellers. If I have to worry that bad about
whether

I'm gonna get a functional unit or not... "so far two out of two were
junk"

I managed to repair one of them and I use it for building transistor

circuits. So again I know how to use it. But to say it does more that's
not

true. It doesn't do the fault finding in coax the same. That alone is a

feature I'd gladly pay for. And I just prefer the ruggedness of the mfj.

I'm sure with time I'll revisit it. And I'm gonna ask folks on here about

where the right place to buy it is as in who are the reputable sellers. I

think I may have just been getting out some frstration with the
situation.

I guess I bought the mfj because I KNOW it will work and it will come
with

the correct parts. The situation with the nano vna actually caused me

problems with not getting a larger amplifier out on time. And the mfj
makes

it so easy to tune output coils. It generates all the info I need to do
my

job where as the nano vna is all kinds of little screen and if you have

sausage fingers you gotta use the little stylus thjng. Or hook it to the

computer. I figure for that part the mfj is worth what I spent on it. All

frustration aside I will be looking around a little before I buy another

nano vna. Matter of fact.... What's the larger better ones if anyone

doesn't mind... I actually would grab one but I'd like to know where I

should purchase it from so I have better experience with it this time.
Like

do you guys get em on ebay or is there some other outlet to buy them
from?



On Sun, Sep 13, 2020, 7:44 PM David Eckhardt <davearea51a@...>
wrote:



Sorry you had that experience. Likely, you did not take the time to
learn

how to use the NANOVNA!! It is a *FAR* more capable instrument than
anything MFJ offers at 4X the price, but it is not just an antenna
analyzer

which the MFJ product is. The NANOVNA's are not great just for the
price,

but for what they offer the user - IF, and only IF the user is willing
to

learn how to use the instrument. It's no toy!!!!!!!
Dave - W?LEV
On Sun, Sep 13, 2020 at 11:38 PM Brandon Parker <bmanthug@...>
wrote:
I own a Mano vna and I threw it in the toolbox and just paid the 360
bucks
for the mfj with the wall wart without hesitation. Nano vna is
junk. I

have had nothing but problems. I've boughten two now and they were
both

junk. The first one the person I bought it from got mad that I had
put

the
wrong address and sent me a returned item that was broken. I gave up
claiming the replacement because the seller was obviously a pos that
hates
life. And tokk their own hatred out on me. When I was just another
paying

customer. I needed it then and there and instead of just sending me a
good
one they told me to send it back and they would replace it. All set.
Next

one had issues too from an entire different seller. Goes to show the
quality you can expect from a stupid 50 dollar pc of test equipment.
Nope

I'll stick with the pros. And the fact is.... The Nano vna is used
for

different things. It's good for circuit analysis. Like for my
amplifiers

and testing my transformers impedance. But as far as big boy Jobs and
measuring inductance on my coils n such and my antenna tuning I'll
stick

with the mfj. People only speak highly of the Nano vna because it's a
cheap
way out to KIND OF do the job. And I've seen soooooo many bad
reviews
of

bad experiences with buying the nano vna. It's hit or miss. You MIGHT
get a
fully functional unit. But your odds of getting screwed with a junk
one....
Are JUST as good. I'll spend the money and get what the PROS use.
Forget

the nano vna
Just a cheap Chinese knock off type TOY
On Wed, Sep 9, 2020, 12:01 PM OneOfEleven <cmoss296@...>
wrote:

I just watched VE3OSO's comparison video and had a chuckled at the
end

lol.
I've been thinking for a while just how peed off MFJ must be now
that

we
have these extremely useful little VNA's, especially with how much
they

cost. MFJ's sales must have taken a hit I should imagine.
--
*Dave - W?LEV*
*Just Let Darwin Work*






--
73,
Tripp Sanders
K5TRP
Re: NanoVNA vs. MFJ-259B Antenna Analyzer

 

R and L electronics at Randl.com is an authorized dealer in the us.

On Sun, Sep 13, 2020 at 7:14 PM Brandon Parker <bmanthug@...> wrote:

Sorry but that's not the case man. Don't get me wrong it's useful. But my

ability to understand it' is not the issue. My issues with it are the lack

of morals by the people that sold it. I have a certain disgust with the

whole idea of it because the bad luck I've had buying them. And the lack of

support from the crooked sellers. If I have to worry that bad about whether

I'm gonna get a functional unit or not... "so far two out of two were junk"

I managed to repair one of them and I use it for building transistor

circuits. So again I know how to use it. But to say it does more that's not

true. It doesn't do the fault finding in coax the same. That alone is a

feature I'd gladly pay for. And I just prefer the ruggedness of the mfj.

I'm sure with time I'll revisit it. And I'm gonna ask folks on here about

where the right place to buy it is as in who are the reputable sellers. I

think I may have just been getting out some frstration with the situation.

I guess I bought the mfj because I KNOW it will work and it will come with

the correct parts. The situation with the nano vna actually caused me

problems with not getting a larger amplifier out on time. And the mfj makes

it so easy to tune output coils. It generates all the info I need to do my

job where as the nano vna is all kinds of little screen and if you have

sausage fingers you gotta use the little stylus thjng. Or hook it to the

computer. I figure for that part the mfj is worth what I spent on it. All

frustration aside I will be looking around a little before I buy another

nano vna. Matter of fact.... What's the larger better ones if anyone

doesn't mind... I actually would grab one but I'd like to know where I

should purchase it from so I have better experience with it this time. Like

do you guys get em on ebay or is there some other outlet to buy them from?



On Sun, Sep 13, 2020, 7:44 PM David Eckhardt <davearea51a@...>
wrote:



Sorry you had that experience. Likely, you did not take the time to
learn

how to use the NANOVNA!! It is a *FAR* more capable instrument than
anything MFJ offers at 4X the price, but it is not just an antenna
analyzer

which the MFJ product is. The NANOVNA's are not great just for the
price,

but for what they offer the user - IF, and only IF the user is willing to
learn how to use the instrument. It's no toy!!!!!!!
Dave - W?LEV
On Sun, Sep 13, 2020 at 11:38 PM Brandon Parker <bmanthug@...>
wrote:
I own a Mano vna and I threw it in the toolbox and just paid the 360
bucks
for the mfj with the wall wart without hesitation. Nano vna is junk. I
have had nothing but problems. I've boughten two now and they were both
junk. The first one the person I bought it from got mad that I had put
the
wrong address and sent me a returned item that was broken. I gave up
claiming the replacement because the seller was obviously a pos that
hates
life. And tokk their own hatred out on me. When I was just another
paying

customer. I needed it then and there and instead of just sending me a
good
one they told me to send it back and they would replace it. All set.
Next

one had issues too from an entire different seller. Goes to show the
quality you can expect from a stupid 50 dollar pc of test equipment.
Nope

I'll stick with the pros. And the fact is.... The Nano vna is used for
different things. It's good for circuit analysis. Like for my
amplifiers

and testing my transformers impedance. But as far as big boy Jobs and
measuring inductance on my coils n such and my antenna tuning I'll
stick

with the mfj. People only speak highly of the Nano vna because it's a
cheap
way out to KIND OF do the job. And I've seen soooooo many bad reviews
of

bad experiences with buying the nano vna. It's hit or miss. You MIGHT
get a
fully functional unit. But your odds of getting screwed with a junk
one....
Are JUST as good. I'll spend the money and get what the PROS use.
Forget

the nano vna
Just a cheap Chinese knock off type TOY
On Wed, Sep 9, 2020, 12:01 PM OneOfEleven <cmoss296@...> wrote:
I just watched VE3OSO's comparison video and had a chuckled at the
end

lol.
I've been thinking for a while just how peed off MFJ must be now that
we
have these extremely useful little VNA's, especially with how much
they

cost. MFJ's sales must have taken a hit I should imagine.
--
*Dave - W?LEV*
*Just Let Darwin Work*






--
73,
Tripp Sanders
K5TRP
Re: Writing nanovna results to csv file #nanovna-saver

 

I have been saving s1p and s2p files from Saver and then re-save them as .txt files. In Excel I import external data in the .txt format and delimit using spaces. This works well for using S21 Thru and S21 Shunt methods for calculating low impedances and high impedances. Having a great time with this little NanoVNA. BTW, when I was involved with hp network analyzers never heard the term VNA for them as it was assumed they could measure the amplitude and phase. They were referred to as network analyzers. Or scaler network analyzers for those that could not determine phase relationships (they used diode detectors only).
Re: NanoVNA vs. MFJ-259B Antenna Analyzer

Brandon Parker
 

Sorry but that's not the case man. Don't get me wrong it's useful. But my
ability to understand it' is not the issue. My issues with it are the lack
of morals by the people that sold it. I have a certain disgust with the
whole idea of it because the bad luck I've had buying them. And the lack of
support from the crooked sellers. If I have to worry that bad about whether
I'm gonna get a functional unit or not... "so far two out of two were junk"
I managed to repair one of them and I use it for building transistor
circuits. So again I know how to use it. But to say it does more that's not
true. It doesn't do the fault finding in coax the same. That alone is a
feature I'd gladly pay for. And I just prefer the ruggedness of the mfj.
I'm sure with time I'll revisit it. And I'm gonna ask folks on here about
where the right place to buy it is as in who are the reputable sellers. I
think I may have just been getting out some frstration with the situation.
I guess I bought the mfj because I KNOW it will work and it will come with
the correct parts. The situation with the nano vna actually caused me
problems with not getting a larger amplifier out on time. And the mfj makes
it so easy to tune output coils. It generates all the info I need to do my
job where as the nano vna is all kinds of little screen and if you have
sausage fingers you gotta use the little stylus thjng. Or hook it to the
computer. I figure for that part the mfj is worth what I spent on it. All
frustration aside I will be looking around a little before I buy another
nano vna. Matter of fact.... What's the larger better ones if anyone
doesn't mind... I actually would grab one but I'd like to know where I
should purchase it from so I have better experience with it this time. Like
do you guys get em on ebay or is there some other outlet to buy them from?

On Sun, Sep 13, 2020, 7:44 PM David Eckhardt <davearea51a@...> wrote:

Sorry you had that experience. Likely, you did not take the time to learn
how to use the NANOVNA!! It is a *FAR* more capable instrument than
anything MFJ offers at 4X the price, but it is not just an antenna analyzer
which the MFJ product is. The NANOVNA's are not great just for the price,
but for what they offer the user - IF, and only IF the user is willing to
learn how to use the instrument. It's no toy!!!!!!!

Dave - W?LEV

On Sun, Sep 13, 2020 at 11:38 PM Brandon Parker <bmanthug@...>
wrote:

I own a Mano vna and I threw it in the toolbox and just paid the 360
bucks
for the mfj with the wall wart without hesitation. Nano vna is junk. I
have had nothing but problems. I've boughten two now and they were both
junk. The first one the person I bought it from got mad that I had put
the
wrong address and sent me a returned item that was broken. I gave up
claiming the replacement because the seller was obviously a pos that
hates
life. And tokk their own hatred out on me. When I was just another paying
customer. I needed it then and there and instead of just sending me a
good
one they told me to send it back and they would replace it. All set. Next
one had issues too from an entire different seller. Goes to show the
quality you can expect from a stupid 50 dollar pc of test equipment. Nope
I'll stick with the pros. And the fact is.... The Nano vna is used for
different things. It's good for circuit analysis. Like for my amplifiers
and testing my transformers impedance. But as far as big boy Jobs and
measuring inductance on my coils n such and my antenna tuning I'll stick
with the mfj. People only speak highly of the Nano vna because it's a
cheap
way out to KIND OF do the job. And I've seen soooooo many bad reviews of
bad experiences with buying the nano vna. It's hit or miss. You MIGHT
get a
fully functional unit. But your odds of getting screwed with a junk
one....
Are JUST as good. I'll spend the money and get what the PROS use. Forget
the nano vna
Just a cheap Chinese knock off type TOY

On Wed, Sep 9, 2020, 12:01 PM OneOfEleven <cmoss296@...> wrote:

I just watched VE3OSO's comparison video and had a chuckled at the end
lol.

I've been thinking for a while just how peed off MFJ must be now that
we
have these extremely useful little VNA's, especially with how much they
cost. MFJ's sales must have taken a hit I should imagine.







--
*Dave - W?LEV*
*Just Let Darwin Work*
Re: NanoVNA vs. MFJ-259B Antenna Analyzer

 

Sorry you had that experience. Likely, you did not take the time to learn
how to use the NANOVNA!! It is a *FAR* more capable instrument than
anything MFJ offers at 4X the price, but it is not just an antenna analyzer
which the MFJ product is. The NANOVNA's are not great just for the price,
but for what they offer the user - IF, and only IF the user is willing to
learn how to use the instrument. It's no toy!!!!!!!

Dave - W?LEV

On Sun, Sep 13, 2020 at 11:38 PM Brandon Parker <bmanthug@...> wrote:

I own a Mano vna and I threw it in the toolbox and just paid the 360 bucks
for the mfj with the wall wart without hesitation. Nano vna is junk. I
have had nothing but problems. I've boughten two now and they were both
junk. The first one the person I bought it from got mad that I had put the
wrong address and sent me a returned item that was broken. I gave up
claiming the replacement because the seller was obviously a pos that hates
life. And tokk their own hatred out on me. When I was just another paying
customer. I needed it then and there and instead of just sending me a good
one they told me to send it back and they would replace it. All set. Next
one had issues too from an entire different seller. Goes to show the
quality you can expect from a stupid 50 dollar pc of test equipment. Nope
I'll stick with the pros. And the fact is.... The Nano vna is used for
different things. It's good for circuit analysis. Like for my amplifiers
and testing my transformers impedance. But as far as big boy Jobs and
measuring inductance on my coils n such and my antenna tuning I'll stick
with the mfj. People only speak highly of the Nano vna because it's a cheap
way out to KIND OF do the job. And I've seen soooooo many bad reviews of
bad experiences with buying the nano vna. It's hit or miss. You MIGHT get a
fully functional unit. But your odds of getting screwed with a junk one....
Are JUST as good. I'll spend the money and get what the PROS use. Forget
the nano vna
Just a cheap Chinese knock off type TOY

On Wed, Sep 9, 2020, 12:01 PM OneOfEleven <cmoss296@...> wrote:

I just watched VE3OSO's comparison video and had a chuckled at the end
lol.

I've been thinking for a while just how peed off MFJ must be now that we
have these extremely useful little VNA's, especially with how much they
cost. MFJ's sales must have taken a hit I should imagine.







--
*Dave - W?LEV*
*Just Let Darwin Work*
Re: NanoVNA vs. MFJ-259B Antenna Analyzer

[email protected]
 

I own a Mano vna and I threw it in the toolbox and just paid the 360 bucks
for the mfj with the wall wart without hesitation. Nano vna is junk. I
have had nothing but problems. I've boughten two now and they were both
junk. The first one the person I bought it from got mad that I had put the
wrong address and sent me a returned item that was broken. I gave up
claiming the replacement because the seller was obviously a pos that hates
life. And tokk their own hatred out on me. When I was just another paying
customer. I needed it then and there and instead of just sending me a good
one they told me to send it back and they would replace it. All set. Next
one had issues too from an entire different seller. Goes to show the
quality you can expect from a stupid 50 dollar pc of test equipment. Nope
I'll stick with the pros. And the fact is.... The Nano vna is used for
different things. It's good for circuit analysis. Like for my amplifiers
and testing my transformers impedance. But as far as big boy Jobs and
measuring inductance on my coils n such and my antenna tuning I'll stick
with the mfj. People only speak highly of the Nano vna because it's a cheap
way out to KIND OF do the job. And I've seen soooooo many bad reviews of
bad experiences with buying the nano vna. It's hit or miss. You MIGHT get a
fully functional unit. But your odds of getting screwed with a junk one....
Are JUST as good. I'll spend the money and get what the PROS use. Forget
the nano vna
Just a cheap Chinese knock off type TOY

On Wed, Sep 9, 2020, 12:01 PM OneOfEleven <cmoss296@...> wrote:

I just watched VE3OSO's comparison video and had a chuckled at the end lol.

I've been thinking for a while just how peed off MFJ must be now that we
have these extremely useful little VNA's, especially with how much they
cost. MFJ's sales must have taken a hit I should imagine.
Re: NanoVNA vs. MFJ-259B Antenna Analyzer

 

Don't forget, the NANOVNA also connects to a PC as does the Rig Expert
units. I usually use mine connected to the PC.

Dave - W?LEV

On Sun, Sep 13, 2020 at 10:59 PM Roger Need via groups.io <sailtamarack=
[email protected]> wrote:

On Sun, Sep 13, 2020 at 12:27 PM, ve3zt wrote:


Not just MFJ. RigExpert too!
I have a MFJ-259B, A Rig-Expert AA-55 Zoom and a nanoVNA-H.

Each one is useful depending on the task at hand. I use the MFJ-259B when
adjusting my manual tuner because the needles quickly respond to
adjustments. It also has a nice frequency counter built-in and works well
as signal generator up to 170 MHz. It also is handy when I want to do a
quick SWR measurement.

The Rig-Expert is actually one port VNA and it has a lot of features which
make it better for antenna tuning than a NanoVNA. The multi-band screens
are nice when tuning fan dipoles or antennas like a G5RV. You can save
sweeps for later reference and it has built-in calibration but you can
calibrate a reference plane. Also is fairly accurate when measuring
inductors or capacitors. The ability yo hook it up to a PC and use
AntScope software to download saved data at the antenna is a nice feature.
I use it a lot.

The NanoVNA goes much higher in frequency than either of the other two and
that is one of the biggest advantages for me. The other is that it is a 2
port device so I can measure coax cable attenuation, filter characteristics
and network sweeps. I mainly use it with NanoVNA Saver for the added
features and big screen plots.

In summary each device has its place on my workbench...

Roger



--
*Dave - W?LEV*
*Just Let Darwin Work*
Re: NanoVNA vs. MFJ-259B Antenna Analyzer

 

On Sun, Sep 13, 2020 at 12:27 PM, ve3zt wrote:


Not just MFJ. RigExpert too!
I have a MFJ-259B, A Rig-Expert AA-55 Zoom and a nanoVNA-H.

Each one is useful depending on the task at hand. I use the MFJ-259B when adjusting my manual tuner because the needles quickly respond to adjustments. It also has a nice frequency counter built-in and works well as signal generator up to 170 MHz. It also is handy when I want to do a quick SWR measurement.

The Rig-Expert is actually one port VNA and it has a lot of features which make it better for antenna tuning than a NanoVNA. The multi-band screens are nice when tuning fan dipoles or antennas like a G5RV. You can save sweeps for later reference and it has built-in calibration but you can calibrate a reference plane. Also is fairly accurate when measuring inductors or capacitors. The ability yo hook it up to a PC and use AntScope software to download saved data at the antenna is a nice feature. I use it a lot.

The NanoVNA goes much higher in frequency than either of the other two and that is one of the biggest advantages for me. The other is that it is a 2 port device so I can measure coax cable attenuation, filter characteristics and network sweeps. I mainly use it with NanoVNA Saver for the added features and big screen plots.

In summary each device has its place on my workbench...

Roger
Re: NanoVNA vs. MFJ-259B Antenna Analyzer

 

Not just MFJ. RigExpert too!
Re: Two (joined) cable calibrate and DFU firmware upgrade

 

Ted I struggled with trying to get dfu-util to see my device even though it installed the device drivers. I couldn¡¯t get it to work on a mac but was able to on windows 7 (should also work on 10) using the Zadig utility to install additional drivers needed. Check out this write up. Note: I still can¡¯t access terminal mode to run a ¡°clearconfig¡±. I have the gecko classic.
Re: Resonate frequency of lossy networks... Simple One... #circuit

 

Strictly speaking, there should be bounds on the R,C,L terms so they are less than one. Otherwise a second order system, a tuned network which must posses two memory components vanishes. Consider if R is very large, L is neglected and we have a parallel RC network. No peaking in itself exists. At low frequency and C is no linger a factor and the network is dominate R. At very high frequency, C dominates and the phase shift approaches -90 degrees. So the phase response is one sided, 0 to -90. We never see the so called tuned response of a 2 - element memory (storage) electrical system.
Re: Resonate frequency of lossy networks... Simple One... #circuit

 

What will happen with resonant frequency when R>C/L and value under SQRT becomes negative? Will that create a black hole and the world as we know it will collapse in it? :)

SPICE simulation shows phase approaching zero phase going to the left, but in "aggressive pace" - quite non-asymptotic

Capture2.PNG

Re: Resonate frequency of lossy networks... Simple One... #circuit

 

Alan said:
Here you go Miro. I set the generator to a large value, 1 Meg.
With very large resistance you effectively have current generator so you can plot voltage on the RLC circuit :) In my simulation, I used ideal voltage source and plotted the current - "shapes are the same, but inverted :)

After reading the rest of your response

It is best to look at PHASE and the crossover at zero degree.
I redid my simulation (still with voltage gen and Rg=0), but left PHASE diagram visible - results fully resemble yours - phase lines crossing 0 are visibly shifted to the left indicating change in resonance(as the math says) :)

Honestly I did NOT expect that peaks of amplitude won't be aligned with phase crossing zero (the "real" resonance)! Well, like in some other recent threads (resonance of a dipole antenna), it's important to start with the valid definition - in both cases it's the frequency where phase crosses zero (jX=0), regardless of what amplitude (here) or SWR in the antenna cases might say :)

Great exercise!

Miro
Re: Resonate frequency of lossy networks... Simple One... #circuit

 

And of interest, peak magnitude and zero phase do not always align except for the infinite Q case... It is best to observe the definition as the imaginary part of the function goes to zero implies the phase shift of the network goes to zero. Hence, inspection of the amplitude response only is problematic.
Re: Two (joined) cable calibrate and DFU firmware upgrade

 

I've purchased some well made cables with SMA males on each end from Amazon to replace the jumper cables that come with a typical basic NanoVNA - as others have mentioned on here, the quality control varies with the cables included with the basic NanoVNA kit - I own three (basic "H" version) NanoVNA's, and over time, two of the cables have become intermittent. I have also shopped around trying different vendors that make the double-female SMA connector (the "Thru" connector) as I found a few that get intermittent with use - you'll know something is not right after you complete a calibration session and discovered what looks like a 3 year old had scribbled on the smith chart of the NanoVNA display - that's a warning sign that you have an intermittent cable, connector or thru adapter - you'll then need to isolate which item is intermittent, replace it and then re-do your calibration process.

Brian - KI8KY
Re: Resonate frequency of lossy networks... Simple One... #circuit

 

So on the plot shown you can see the migration in resonant frequency from 15.9 MHz readily down to 12 MHz and still marching downward. I said infinite Q.... nah! Actually quite finite, maybe 50 or something can't recall, but large enough that you get the point...

Alan
Re: Resonate frequency of lossy networks... Simple One... #circuit

 

Here you go Miro. I set the generator to a large value, 1 Meg.

It is best to look at PHASE and the crossover at zero degree.

You will see zero degree phase point in the plot as a RED crossover X. It is centered on the ideal infinite Q point to start. Note with progressive increase in RL... the series loss of the shunt inductor, there is a significant shift LEFT as marked by the dotted sweeps of phase.

Alan

The LC tuned ckt exp with loss.jpg

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