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The proper instrument to use for this application would be the TinySA
Ultra, a spectrum analyzer. The input power is still a problem. Typically
less than 0 dBm (1 mW) at 50-ohms non-reactive.

Dave - W?LEV

--
Dave - W?LEV

Exist different HC-05 modules, my old allow stable work on 460800, but last ordered allow only on 115200.

Yes tou can use Serial->WiFi converter, it allow more faster speed (up to 3M) and autor NanoVNA-App add it support (but this converer can increase noise floor in S21 measures, but not critical in S11 like SWR)

AT commands can executed over nanoVNA (NanoVNA in USB mode, use NanoVNA-App and nanoVNA usart comm button for console, select current device speed and send AT commands)

Many thanks to all.

Phil

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-----Original Message-----
From: [email protected] <[email protected]> On Behalf Of Philip Stevens
Sent: Thursday, December 1, 2022 8:24 AM
To: [email protected]
Subject: Re: [nanovna-users] Updated Wiki Page: Home #wiki-notice

How does one start a new topic?
I see no link to enable this need below all correspondence.
Phil

On Thu, 1 Dec 2022 at 12:39, Group Notification <[email protected]> wrote:

The wiki page Home ( /g/nanovna-users/wiki/12336/177482
) has been updated by Larry Rothman <nlroth@...>.

*Reason:* updated info on DiSlord's modified NanoVNA-App for LiteVNA

Compare Revisions (
/g/nanovna-users/wiki/12336/history?dataid=177482&dataid=176843
)

On Thu, Dec 1, 2022 at 02:24 PM, Philip Stevens wrote:

How does one start a new topic?

On the left of the messages you can select "New Topic".

On 11/30/22 4:28 PM, Christian Cowell wrote:

Hello fellow techies,
I'm currently in the process of changing a test method for two similar communications antennas. The Tx antennae output 908MHz and 922MHz respectively at ~6.4mW^3. my current test setup is extremely drawn out and is slight overkill. Testing for only power levels, could the nanoVNA be of any help and here as I'm switching to a free space radiation procedure to quickly provide a functional check of these antennae.
My concerns are;
1.Will the power levels damage the nanoVNA?
2. Can this be attached to a receiver with a straight connection to the nanoVNA via RF cable to measure power levels?
3. How accurate are the measurements over distances of ~40ft.
4. Is this even viable?
Very Respectfully,
Christian C. Cowell

I would suggest that the TinySA ( a small spectrum analyzer) might be a better way to measure your radiated RF power at a distance. As to accuracy, what you're talking about is setting up a small antenna range. What you'll need to worry about is reflections off the ground between the Device under test and the probe antenna connected to the measurement receiver (the TinySA or other).

How does one start a new topic?
I see no link to enable this need below all correspondence.
Phil

Fran?ois,


I highly appreciate the clarification and feared this would be the case. I recently stumbled across the nanoVNA in another forum. After lightly researching the product through Amazon I wasn't entirely sure of the capabilities as many are sold with some thorough modifications.

Nonetheless I'm highly impressed by the product and the community of users!

Merci de bien vouloir,
Christian

The wiki page Home ( /g/nanovna-users/wiki/12336/177482 ) has been updated by Larry Rothman <nlroth@...>.

*Reason:* updated info on DiSlord's modified NanoVNA-App for LiteVNA

Compare Revisions ( /g/nanovna-users/wiki/12336/history?dataid=177482&dataid=176843 )

In the current firmware there is an option to control the device through the serial port, instead of the usb port. (Menu/Config/Connection/Serial and Serial Speed)
I used a Serial/Bluetooth HC-05 converter, which I connected to the NanoVNA pcb and connected to this converter from the PC via Bluetooth, and in the operating system I could see the serial port of the converter, which I pointed to in the NanoVNA-App. It worked.
The HC-05 converter required configuration with AT commands. I no longer remember how it was done, but it worked. I was not satisfied with the communication speed, despite the 115200 setting. At higher speeds there were transmission errors.
I read somewhere that there are Serial/Wifi converters on which higher speeds can be achieved, but I don't have one and haven't tried it. In NanoVNA-App there is an option to specify ip address and port. Probably it is to support such a Serial/Wifi converter, but I am not sure.

With the jet lag, I dare an answer

My concerns are;

1.Will the power levels damage the nanoVNA?

*Yes

2. Can this be attached to a receiver with a straight connection to the nanoVNA via RF

cable to measure power levels?

*No

3. How accurate are the measurements over distances of ~40ft.

*Measure a power at 100 times the wavelength can be significant but how to calibrate your probe. You can only make comparative measures

4. Is this even viable?

*It seems to me that what you want to do is not in the field of a VNA which is only a measurement bridge. You can use your VNA in transition between your trial antenna and a probe placed at 40ft. The field can be sufficient but you will lack dynamics



73

--

F1AMM Fran?ois

-----Message d'origine-----

De la part de Christian Cowell

jeudi 1 décembre 2022 01:28

Hello fellow techies,

I'm currently in the process of changing a test method for two similar communications antennas. The Tx antennae output 908MHz and 922MHz respectively at ~6.4mW^3. my current test setup is extremely drawn out and is slight overkill. Testing for only power levels, could the nanoVNA be of any help and here as I'm switching to a free space radiation procedure to quickly provide a functional check of these antennae.
My concerns are;
1.Will the power levels damage the nanoVNA?
2. Can this be attached to a receiver with a straight connection to the nanoVNA via RF cable to measure power levels?
3. How accurate are the measurements over distances of ~40ft.
4. Is this even viable?

Very Respectfully,
Christian C. Cowell

It's been almost 3 years since the previous posting.
Anyone made any progress yet?
--
Doug, K8RFT

On Tue, Nov 29, 2022 at 11:03 AM, <dalerheaume@...> wrote:

...given that the phase measurement is
reflected, is 1 degree phase difference between cables actually 2 degrees.

Other way around. 2 degrees measured in reflection (out and back) is 1 deg one way.

Yes, that technique should work fine.


On Tue, Nov 29, 2022 at 10:03 AM dalerheaume via groups.io <dalerheaume=
[email protected]> wrote:

Hi Stan,

Thank you very much for your very informative and thorough response.

I'm finally back at this and would appreciate your thoughts on what I did
to achieve phase matching although somewhat different from what you shared
at the end of your reply.

I setup the stimulus close to my target frequency of 1.1 GHz.
Start Stimulus 1.098 GHz
Stop Stimulus 1.108 GHz
The smith circle is just over half a circle in this case.

I formatted S11 as SMITH LIN to measure phase angle.

I physically measured the following two cables then measured the phase
angle with marker set at 1.1 GHz:
CBL-1 20FT 0.50IN -33.1deg
CBL-2 20FT 0.63IN -54.8deg

After trimming CBL-2 by approximately 0.25IN, I measured the phase angle
for CBL-2 at -35.8deg...a difference of 2.7 from CBL-1 and within the
specification of +/-5 degrees.

Is this method acceptable, also, given that the phase measurement is
reflected, is 1 degree phase difference between cables actually 2 degrees.

Thanks,
Dale

On Tue, Nov 15, 2022 at 02:52 PM, Stan Dye wrote:

Another perhaps better way is to not use the TDR mode, but (if your
firmware has it) the Measure / Cable function. Leave the cable open at

the

end. Set the top frequency of the vna such that the smith chart trace is
just over a half-circle. Then note the length of the cable shown. Trim
the other cable to show that same length. You can ignore the velocity
factor and whether or not the length is correct to measured length, since
you only need them to match electrically. This method is usually more
accurate, because it measures the quarter-wavelength resonance of the

cable

by finding the phase crossing, using excellent interpolation between
measured frequency points.

Good luck.

Stan

Just a quick update. I received several new SA602AD chips just before Thanksgiving. I ordered the "602" because that's what was in there originally.
The unit calmed down considerably but still not responsive to any input. (connected to a 50 ohm dummy load or antenna.
I did a reset as well as several complete calibrations but still no input response.
I made sure there was contact to the board on all 8 legs of the 602 chip. No bridges between legs.
I checked the components prior to the chip and they show normal values. Mostly tiny SMD resistors.
So, something is really hosed.
Thanks.

John / K7RLD

Hi Stan,

Thank you very much for your very informative and thorough response.

I'm finally back at this and would appreciate your thoughts on what I did to achieve phase matching although somewhat different from what you shared at the end of your reply.

I setup the stimulus close to my target frequency of 1.1 GHz.
Start Stimulus 1.098 GHz
Stop Stimulus 1.108 GHz
The smith circle is just over half a circle in this case.

I formatted S11 as SMITH LIN to measure phase angle.

I physically measured the following two cables then measured the phase angle with marker set at 1.1 GHz:
CBL-1 20FT 0.50IN -33.1deg
CBL-2 20FT 0.63IN -54.8deg

After trimming CBL-2 by approximately 0.25IN, I measured the phase angle for CBL-2 at -35.8deg...a difference of 2.7 from CBL-1 and within the specification of +/-5 degrees.

Is this method acceptable, also, given that the phase measurement is reflected, is 1 degree phase difference between cables actually 2 degrees.

Thanks,
Dale

Hello to All,

This story points out something that I have been trying to point out for years.? Many of us have been trying to get youngsters to get their tickets and get on the air.? This is important, but more important in my experience has been to "plant the seed" about amateur radio.? Many hams have gotten their tickets later in life.? Many have done this due to the seed being planted years ago.? Sometimes we just have to be patient.

73, Joe, K1ike

I got into radio at the tender age of four years old, when my dad and I
built a crystal set together that he got me for Christmas. I learned a lot
about radio then that never left me, and as I grew up through the hifi era
and building stereos and playing with CB radios, I really began to take my
knowledge of radio for granted. I told myself one day I’d take my ticket.
One day. Decades later, after a career in information technology, I
realized I really knew quite a bit about radio, and now approaching 60
years old, I really probably ought to take that technician’s ticket if I
was ever going to.

So I spent the time until I could get a test doing the practice exams. I
never failed one, and taking the exam for my ticket felt like a formality.

I’m still not transmitting; I got super busy with work (full stack python
development; I’m the project architect/lead dev), and it just hasn’t left
me much time for radio. I’m not concerned though, I’ve got my o scope, vna,
meters, soldering station and breadboards all near to hand, alongside a
pretty fair collection of parts, hookup wire and magnet wire, and they’ll
be right there the next time I get ready to build a new vackar oscillator.

I guess the tl;dr is, radio isn’t a hobby for me, more like a facet of my
existence, and I reckon after I die I’ll just be a dead radio guy. Until
then, the most interesting tool is the one I don’t have and don’t know how
to use : D

Cheers, and thanks for the conversation!

On Tue, Nov 29, 2022 at 7:30 AM David Wilcox K8WPE via groups.io
<Djwilcox01@...> wrote:

sparseMatrix,

While I agree with your thoughts the level of todays technician licensee
is super low. They don’t want to study any more than the question pool and
think their license will give them the wonderful shack full of neat things
that I and others have collected over many years of study. What I see
mostly is sad disappointed folks who buy things because they are impressive
in others hands but who don’t stay long enough in the hobby to obtain the
same (equipment and experience). You either have the true interest to dig
further or you don’t have it. I hand out an eyeball QSL card to all new
hams and interested folks I meet and rarely does anyone contact me to learn
more. I am a VE and am in touch with many “interested” prospective hams
and see real little interest after getting their tech license. The two I
am mentoring now are 52 and 82 years old and they are a hoot….. always
asking questions I can’t answer but making me re learn more to help them
understand. After the first buying fever is over then we can tell who will
really be in this hobby a year from now.

They should ALL buy a NanoVNA right away so I can buy it from them later
(much cheaper) to GIVE to a truly interested ham.

Dave K8WPE since 1960

David J. Wilcox’s iPad

On Nov 29, 2022, at 7:05 AM, sparseMatrix <james.stallings@...>

wrote:

?You guys finally chased me out of my dark lurking corner.

The nano VNA is a brilliant tool that can be succinctly described in as
little language as it takes to give advice. Same with any VNA really.

The VNA measures electrical potential, either in terms of electrical
potential stored as a magnetic field (inductance) or as a surface charge

on

a conductor (capacitance). It is because of this that the device is so
useful in tuning antennae, as it can measure both independently, as well

as

their interaction and related products.

This device cost me around 60$. It’s half the cost of a night out. Buy

the

damn thing, and immediately open the package, get the thing out, and
calibrate it. You’ll learn enough from this to get a proper understanding
of what the device does.

Now concerning what it is used for and how it is used to do specific
things, e.g., tuning antennae, measuring the impedance of a coil or the
capacitance of a capacitor, that is a bit different.

The ‘N’ in VNA is for ‘network’, and refers to the classical
resistor/capacitor network so often employed in radio frequency tuners.

The thing that makes these applications challenging is that the

performance

of these devices is non-static. One does not simply take a meter and

read a

value off a capacitor; how it functions over time, or how it ‘cycles’ is

a

key feature; especially when combined into a network.

Consequently, one needs a device that can plot these measurements in real
time.

The point is, you probably need this and don’t yet know it. There will

come

a time, though when you will need it and know it, and when you do reach

for

such a device, it will be with purpose. You will seek out documentation

and

learn to take the measurements you need to take to refine the design to
your tuner or adjust your antennae or to assess the condition of all

those

salvaged caps you fell into.

This is how and why I got it, to make certain that the dipole antenna I
built in the rafters in my attic was doing what I thought it was doing.

So you’re not an active Ham yet, just studying theory and trying to learn
all the things? If you have the 60$ to spare, get one. It might be a good
thing to build yourself, but if you want it to be ‘right’ as a tool,

maybe

not. I guess it depends on your fabrication fu. I’m damn good with solder
and pen, but I opted to purchase one assembled and tested.

The big thing about this device is that it is tiny and stuffed with

digital

conveniences, e.g., it has builtin analytical capabilities and a fairly
high resolution screen on which to plot measurements.

Until this device was delivered, the nearest similar tool was industrial,
hundreds of times the size of the nano, and a thousand times the price,

and

probably didn’t do half as much.

Truth be told, that’s why the technical specifics of proper use and
operation are so scarce; most of us, in decades past, simply wouldn’t

have

access to such a device, except MAYBE a few of us, at work.

Just my .02c, but don’t let people mystify things for you. Don’t respect
‘learning curves’. Those ‘curves’ are meant to be flattened. If you hold

a

technician’s ticket or better, you should already know everything you

need

to know to quickly take up and use this tool.

Good luck, stay chill and hack the planet!

KI5SMN/EL29kl

On Tue, Nov 29, 2022 at 5:18 AM David Wilcox K8WPE via groups.io
<Djwilcox01@...> wrote:

I agree with this response. So many ham friends bought nanoVNAs because
they were cheap but few have taken the time to learn what they were for

or

how to use them. It’s a fantastic tool even if just used for antenna
tuning but there is a learning curve. If you can find someone who has

one

and will come to your shack and test your antenna with it AND explain

what

he is doing in the process.

I too have used an SWR bridge and a noise bridge for years before these
low cost analyzers came out. They both worked for what I needed. Do a

lot

of reading before spending your money. Watch many Youtube videos about
them. That should tell you if you are willing to climb the learning

curve

and know what and why. Otherwise if you are a newbie it will just be
another box sitting in a cupboard in your shack. The most important

part

of your shack will be outside, the antenna. Have another ham advise and
assist you in getting your first antenna up and tuned. Once that is done
you are ready for whatever goes on and into your shack.

I am available if you have questions. As for antenna tuning borrow
someone’s antenna analyzer first and if possible have them come an show

you

what it does and how to use it. Most hams I know would do better
purchasing a good antenna analyzer instead of the NanoVNA . It’s just

that

the NanoVNA is very low cost and that causes many hams to buy one but

not

spend the time to learn how to use it.

Dave K8WPE since 1960

David J. Wilcox’s iPad

On Nov 29, 2022, at 6:05 AM, tuckvk3cca <tuckvk3cca@...> wrote:

?Never buy in haste. For an instrument like this try buying a cheap

second hand one and familiarise yourself first. In fact I build my own

nano

vna, works up to 60MHz ok. Even have all the bells and whistles like
Bluetooth and mobile apps. But the real issue is whether you understand
enough about vnas, S parameters measurements to make owning such a

piece if

gear worthwhile. I lived with an swt meter and a noise bridge for eons

when

I first started. Still using them.

--

?? ? ?? ????? ? ? ??
KI5SMN

--

?? ? ?? ????? ? ? ??
KI5SMN

On Mon, Nov 28, 2022 at 07:23 AM, <forum@...> wrote:

Doug, is there an obvious way I can identify which version VNA I have via
inspection of the circuit board? I have a 2.8” that is probably 3 years old.
I do know that there is no “config” menu choice thus I must short the pins
when I do get around to upgrading the firmware. I just do not know if I have a
“H” edition.

No, I do not know of any circuit board reference that you could use.
My 3 year old 2.8 inch model was an early "copy" or clone versioin, with no shielding on the PC boards. it has the 2 terminals to short together for putting it into DFU mode for firmware update. But this Nano still works fine, and runs the latest firmware. Newer firmware, DisLord in particular, now have a menu choice for going to DFU mode for firmware update and then the "short the pins" step is not needed. NanoVNA-APP can update the firmware "all by itself" from a menu choice in the program.f

I would say "Get a Nano soon! Try it, learn it, and if you don't like it, then sell it and get a better one." Any nanovna is FAR, far better than having no nanovna.
Warning - you may need MANY connector adapters! I think I have spend as much money on adapters as I did for the first Nano (about $45).
My old, early, cheaply-made clone or copy, poor as it may be, still makes the antennas tests for me, and I use it a lot.
Later, I bought a NanoVNA-F, so that I would be able to read the display screen while outdoors. But for indoor measurements, and for measuring while connected to the computer, the 2.8 inch cheap clone is good - because the new DisLord firmwares have so many useful features.

Don't wait - jump in. It's not a "once in a lifetime" opportunity. You can change your mind later, and upgrade to any other model - if you need to. Personally, I like having the two different models - and I plan to soon order a -H with the v4.3 hardware, to have the clock/calendar and SD card slot. (No, I don't "need" it, but I do want it.)
-
Doug

--
Doug, K8RFT