Hello everyone,

Sorry for the wrong translation.

I am new and I am French. I have 68 years old, and I have been interested in radio since the 1970s.
I would like to buy a Nanovna for my HF, VHF and UHF antennas but in front of the number of version and clones, I do not know what to take.
I would like a closed box if possible because I can be brought to transport it.

I live in the center France and my name is Pascal

Amicably to everyone
Pascal :)

Hi Pascal,
considering your age, which is more or less mine, I recommend a model that has a screen of at least 4 inches. Those with smaller screens are difficult to read at a certain age. :)

Hello,

I got the V2 Plus4 from the official store on Tindie, which is the latest version with a 4 inch display. Even below a gigahertz the noise improvements are worth it to upgrade from a NanoVNA.

https://www.tindie.com/products/hcxqsgroup/nanovna-v2-plus4/

Regards

On 28/02/2021 18:51, pcast.fr@gmail.com wrote:
> Hello everyone,
> Sorry for the wrong translation.
> I am new and I am French. I have 68 years old, and I have been
> interested in radio since the 1970s.
> I would like to buy a Nanovna for my HF, VHF and UHF antennas but in
> front of the number of version and clones, I do not know what to take.
> I would like a closed box if possible because I can be brought to
> transport it.
> I live in the center France and my name is Pascal
> Amicably to everyone
> Pascal :)

Pascal,

I would recommend the larger screen device, and my most recent one seems
to work very well to 4 GHz, but it's out of stock:

https://www.tindie.com/products/hcxqsgroup/4-nanovna-v2-plus4/

I also have a 1.5 GHz version which may also suit if you don't need
above 1296 MHz. It's also boxed.

https://www.passion-radio.com/meter/nanovnaf-945.html

Measuring antennas can be difficult, so seek advice here if the results
are not quite what you expect!

Cheers,
David GM8ARV
--
SatSignal Software - Quality software for you
Web: https://www.satsignal.eu
Email: david-taylor@blueyonder.co.uk
Twitter: @gm8arv

In my opinion, the NanoVNA is a great, useful, and educational instrument
for BENCH use.
But since it has ZERO input ESD and static protection, I question the
usefulness of this tool
for outdoor antenna measurements.

There are more than a few people on this forum that have blown up their
NanoVNA, even
using it on the workbench, who likely did not understand ESD precautions,
and/or did not
understand that the NanoVNA has no (or very weak) ESD protection on the
inputs.

A slight breeze outdoors, passing your antenna, can generate over several
thousand volts of
static electricity. I personally use a device purposely built as an
antenna analyzer, and
it has protection built in, but of course, we get what we pay for.

While the nanoVNA has all the proper measurement functions and capability
to be used
for antenna measurements, it does NOT have the protections that formal
antenna analyzers
do. It was not purpose built as an antenna analyzer, with those specific
functions. Rather,
it was designed as a general purpose educational tool, toward a price
point, which precluded
inclusion of significant input protection devices.

My personal opinion? I am only connecting my antennas to my Rig Expert
analyzer.
I am using my nanoVNA on the bench, and I use an ESD bench surface pad and
an
ESD wrist-strap connected to an ESD monitor alarm. Not that expensive,
but since I
keep reading about people blowing these nanoVNA's up, I am not taking
chances with
mine.

Your mileage may vary. Your preferences may vary. If you wish to keep
your NanoVNA working
for more than half a season, I'd suggest the below short reading.

REF:

https://www.ece.ubc.ca/~robertor/Links_files/Files/understanding_esd.pdf

https://www.electronics-notes.com/articles/constructional_techniques/electrostatic-discharge/esd-basics.php

Cheers,

Neal

Hello Neal,

You scare me. I don't know what to think, let alone what to buy. Yes, this is the external antenna for me, especially UHF.

Yes, occasionally, but it's quite rare when I deal with my PL259 or N, which happens when I have a small ESD. If my future nano is connected to a coaxial line, it will burn out.
I'm not going to buy the equipment for more than I can afford. Besides, I'm useless. I set myself a price of up to $150. But if I'm going to lose them randomly in an electrostatic wave, I'll think many times, as cheaply as possible, even if I have to look at the results with a magnifying glass;)

Thank you all for replying to me and I'll see all the links.

Ciao, Pascal

The ports on the V2 plus4 are rated for ESD up to 1000V (human body
model), but only 100V (machine model). In my tests it's susceptible to
static discharge through a long transmission line, but not susceptible
to slow charge buildup (that gets clamped very easily). If you discharge
antennas and cable before connecting to the VNA it should be safe.

best thing to buy ... a v2plus4 (v2 with metal case and 4 inch screen
and improved pcb design)

do not buy the normal older nanovna ... get a v2 (or a "good" clone)

dg9bfc sigi


Am 02.03.2021 um 02:09 schrieb Pascal CASTRATARO:

> Hello Dragan Milivojevic
>
> thanks for the advice :)
> Where do you find in stock?
>
>
> Le mar. 2 mars 2021 à 02:46, Dragan Milivojevic
> <d.milivojevic@gmail.com <mailto:d.milivojevic@gmail.com>> a écrit :
>
> Just buy a NanoVNA H4 (around $50). You do not need anything better
> than that.
>
> On Tue, 2 Mar 2021 at 00:17, <pcast.fr@gmail.com
> <mailto:pcast.fr@gmail.com>> wrote:
>
> Hello Neal,
> You scare me. I don't know what to think, let alone what to
> buy. Yes, this is the external antenna for me, especially UHF.
> Yes, occasionally, but it's quite rare when I deal with my
> PL259 or N, which happens when I have a small ESD. If my
> future nano is connected to a coaxial line, it will burn out.
> I'm not going to buy the equipment for more than I can afford.
> Besides, I'm useless. I set myself a price of up to $150. But
> if I'm going to lose them randomly in an electrostatic wave,
> I'll think many times, as cheaply as possible, even if I have
> to look at the results with a magnifying glass;)
> Thank you all for replying to me and I'll see all the links.
>
> Ciao, Pascal
>
>

As fas as I know, the el cheapo vnas cannot do TDR.

w.

tdr? you mean to measure a cable length?

dg9bfc sigi

Am 02.03.2021 um 05:52 schrieb Helmut Wabnig:

> On Tue, 2 Mar 2021 02:46:00 +0100, you wrote:
>
>> Just buy a NanoVNA H4 (around $50). You do not need anything better
>> than that.
>>
> As fas as I know, the el cheapo vnas cannot do TDR.
>
> w.
>
>
>
>
>

On Tue, 2 Mar 2021 06:09:53 +0000, you wrote:

>tdr? you mean to measure a cable length?
>
>dg9bfc sigi
>

Lenght and quality.
My -F can do it.

w.

all v2 also can do it

and ... a lot more :-)

dg9bfc sigi

ps ... i did not real calibrate it and did not set velocity factor exact
... just wanted to show it works!

Am 02.03.2021 um 06:24 schrieb Helmut Wabnig:

> On Tue, 2 Mar 2021 06:09:53 +0000, you wrote:
>
>> i would buy a v2plus4 or an saa2n
>>
>> tdr? you mean to measure a cable length?
>>
>> dg9bfc sigi
>>
> Lenght and quality.
> My -F can do it.
>
> w.
>
>
>
>
>

Does the v2 versions do interpolation of the calibration? By interpolation I mean you can calibrate for a range of 1 to 30 Mhz. You can then examine a narrower range, such as 14-15Mhz with reasonable accuracy.

Mike N2MS

> On 03/02/2021 4:13 AM Siegfried Jackstien <siegfried.jackstien@freenet.de> wrote:
>
>
> all v2 also can do it
>
> and ... a lot more :-)
>
> dg9bfc sigi
>
>

Latest V2 firmware now supports interpolation calibration.

Also see https://nanorfe.com/nanovna-versions.html. New firmware efforts
are mainly focused on the plus and plus4 versions. There are too many
clones of V2_2 that differ subtly in parts used, and I can't guarantee
support for those. To be most future proof, either go for V1 or the
plus/plus4 versions of V2.

The plus4 is always out of stock. I know chinese new year and so on...
How about a possibility to preorder?

Am 2021-03-02 um 17:13 schrieb OwO:

> Latest V2 firmware now supports interpolation calibration.
>
> Also see https://nanorfe.com/nanovna-versions.html. New firmware efforts
> are mainly focused on the plus and plus4 versions. There are too many
> clones of V2_2 that differ subtly in parts used, and I can't guarantee
> support for those. To be most future proof, either go for V1 or the
> plus/plus4 versions of V2.
>
>

There is a shortage of LCD displays right now, but I think it will be
solved in 2 weeks or so. Everything else (main board, enclosures) are
ready. You can add your email to the waitlist or wait for an
announcement here.

On the TDR topic - what resolution (in distance) is feasible with which of the nanovna variations?
I'm hoping to use this to locate bad connections in house wiring as well as do antenna work.  This
would require a resolution of a couple of inches in a few hundred feet - of branch circuit wiring - i.e.
disconnect wires at panel, and short/open at load-outlet end - testing from panel end - and looking
for bad junction box connections between panel and outlet ...
Thanks,
A relative newbie

the problem is in house wiring you do not have 50 ohms ... and from
panel it goes to first junction box (somewhere in the wall) and from
there it may go to several rooms (depending how much rooms share same fuse)

i would say it will not work well for house wiring ... and now guess
what does happen with an antenna analyzer (and the User!!) when somehow
line voltage gets into play

but for antenna work?? it does work superb ... be it cutting antenna
wires (quarterwave transformers or stubs as notch filters as an example)
... or be it cutting a dipole to resonance ... or whatever

for antenna work such a device is the best you can add to your shack ...
for house wiring ... not so

greetz sigi dg9bfc

ps locating a fault in a network cable (around 100 ohms) should work ...
those have no star connections like house wiring

Am 13.06.2021 um 07:34 schrieb win7hslaw@gmail.com:

> On the TDR topic - what resolution (in distance) is feasible with
> which of the nanovna variations?
> I'm hoping to use this to locate bad connections in house wiring as
> well as do antenna work.  This
> would require a resolution of a couple of inches in a few hundred feet
> - of branch circuit wiring - i.e.
> disconnect wires at panel, and short/open at load-outlet end - testing
> from panel end - and looking
> for bad junction box connections between panel and outlet ...
> Thanks,
> A relative newbie
>

On 13/06/2021 06:34, win7hslaw@gmail.com wrote:
> On the TDR topic - what resolution (in distance) is feasible with which
> of the nanovna variations?
> I'm hoping to use this to locate bad connections in house wiring as well
> as do antenna work.  This
> would require a resolution of a couple of inches in a few hundred feet -
> of branch circuit wiring - i.e.
> disconnect wires at panel, and short/open at load-outlet end - testing
> from panel end - and looking
> for bad junction box connections between panel and outlet ...
> Thanks,
> A relative newbie

Here's the result from a NanoVNA-F sweeping 50 kHz to 1 GHz. As a rough
guide, resolution depends on the maximum frequency, and length limit on
the lowest. 1 GHz has a 30 cm wavelength, which is /very/ approximately
the resolution you see in the attached screenshot. Two inches - 50mm -
6 GHz?

Doubtless someone can give a much more robust explanation.

House wiring? Your guess is as good as mine (and Sigi's is better!).

Cheers,
David
--
SatSignal Software - Quality software for you
Web: https://www.satsignal.eu
Email: david-taylor@blueyonder.co.uk
Twitter: @gm8arv

On 6/12/21 10:34 PM, win7hslaw@gmail.com wrote:
> On the TDR topic - what resolution (in distance) is feasible with
> which of the nanovna variations?
> I'm hoping to use this to locate bad connections in house wiring as
> well as do antenna work.  This
> would require a resolution of a couple of inches in a few hundred feet
> - of branch circuit wiring - i.e.
> disconnect wires at panel, and short/open at load-outlet end - testing
> from panel end - and looking
> for bad junction box connections between panel and outlet ...
> Thanks,
> A relative newbie

The impedance of house wiring isn't 50 ohms (probably more like 100 or
more), but that's no problem, with TDR, what you're looking for is
"discontinuity"

Resolution is more about the frequency span over which you're sweeping -
100 MHz is about a meter (depending on prop velocity) - the max
unambiguous length is determined by the lowest frequency.

j

FWIW: The nanoVNA does not do TDR.  You set a frequency sweep and based on the how the phase of the reflected signal varies over that sweep, in can calculate the electrical distance to the discontinuity that's causing the reflection.  I haven't it tried it in complicated situations where there are multiple discontinuities along the transmission line so don't know how well it would work in situations like that.  Actual TDRs work great for that.

On 6/13/21 7:34 AM, Lou W7HV via groups.io wrote:
> FWIW: The nanoVNA does not do TDR.  You set a frequency sweep and
> based on the how the phase of the reflected signal varies over that
> sweep, in can calculate the electrical distance to the discontinuity
> that's causing the reflection.  I haven't it tried it in complicated
> situations where there are multiple discontinuities along the
> transmission line so don't know how well it would work in situations
> like that.  Actual TDRs work great for that.
> _._,


It will work fine - What the VNA TDR is doing is measuring in the
frequency domain, then doing a Fourier transform to the time domain.

You'll be able to find multiple discontinuities just fine. Attached is a
picture of a (synthetic) TDR with a Keysight Fieldfox sweeping a S-band
feedline and antenna. There's two kinds of coax with different loss in
the feed line, and the actual feed. It's easy to see the coax transitions.

Thanks for all the experience and input.  Yes, Jim, I was thinking that the inverse fft would make this into a tdr, but with some tradeoffs, given its $200-ish not $20k-ish.  I'm still not sure I correctly understand the time domain accuracy and precision. I'm thinking that's a function of step as well as stop frequency?  I'll keep reading, and hope to learn enough to 'jump in' so to speak... 73, kb7efz

Nice.  It'll be interesting to see how a nanoVNA compares to what they Fieldfox can do.

On 6/13/21 9:58 AM, Lou W7HV via groups.io wrote:
> Nice.  It'll be interesting to see how a nanoVNA compares to what they
> Fieldfox can do.
> _._


No reason to think it would be much different. They're comparable in
terms of dynamic range (particularly for this kind of measurement) - the
NanoVNA has somewhat less bandwidth, so it won't have the time
resolution (proportional to 1/BW).

Hmm. If you've got some old coax laying around -  hook it up, sweep it,
hit it with a hammer in a couple places to damage it, and see what it
looks like.  You can easily see things like loose connectors when you
wiggle it.

The time step is 1/frequency span. The unambiguous range is the time step multiplied by the number of frequency samples.

> On Jun 14, 2021, at 05:21, win7hslaw@gmail.com wrote:
>
> Thanks for all the experience and input. Yes, Jim, I was thinking that the inverse fft would make this into a tdr, but with some tradeoffs, given its $200-ish not $20k-ish. I'm still not sure I correctly understand the time domain accuracy and precision. I'm thinking that's a function of step as well as stop frequency? I'll keep reading, and hope to learn enough to 'jump in' so to speak... 73, kb7efz
>

On 6/13/21 8:40 AM, win7hslaw@gmail.com wrote:
> Thanks for all the experience and input.  Yes, Jim, I was thinking
> that the inverse fft would make this into a tdr, but with some
> tradeoffs, given its $200-ish not $20k-ish.  I'm still not sure I
> correctly understand the time domain accuracy and precision. I'm
> thinking that's a function of step as well as stop frequency? I'll
> keep reading, and hope to learn enough to 'jump in' so to speak... 73,
> kb7efz

The bandwidth (# of steps * step frequency) gives the position
resolution. The lowest frequency gives the maximum unambiguous range.

You can also think of it in terms of  Max distance/(# of steps) for the
resolultion - so if you have 101 points, you have coarser resolution (as
displayed) than if you have 401 points.

Interestingly, if you question is "exactly where is the discontinuity" -
you can find that even if it's between points. The typical TDR display
is the magnitude of the Fourier Transform, but there is also phase
information in the transform output (well, not exactly phase, because
it's time domain, but a similar kind of thing)


The accuracy of measurements (as opposed to precision) is really
determined mostly by SNR and consistency of measurement.