开云体育

I think a torque wrench on a nanoVNA is overkill. The ringing I observed was well above the maximum frequency range.

The issue is getting *consistent* connections. Any time you change the sweep parameters you need to do a cal. I think that some means of ensuring more consistent connection torque is needed. But a "finger wrench" should be adequate.

There would be no way to answer your question except by repeating the same measurement many times.

I plan to knurl and slot a small disk of steel or brass rather than put plastic disks on all my SMA connectors. That's just personal preference. A small square or triangle of steel with an 8 mm hole drilled in the center and a slot 8 mm wide cut to the hole should be entirely satisfactory. A 4 mm lever arm is rather short and lots of SMA-M nuts are very smooth.

Have Fun!
Reg

This is a fantastic idea Ken. Just get your "reference" receive antenna as far away as you can and preferably in an open space. Make sure you are not picking up stray radiation from the CH0 "transmit" port" or that the stray signal you see with no antenna connected is overcome when you put the "test" antenna on the CH0 port.

Congratulations on presenting a creative use for the Nanovna. We need to hear more use cases here.

Warren Allgyer
WA8TOD

Ken, you are about to start off on a grand journey.

There is much rubbish physics bandied about regarding antennas. To

get a feel for what's going on permit me to suggest the A.R.R.L.
"Antenna Book", 15th Edition, 1988. The foreword is by John Kraus, W8JK;
if Kraus thinks it's alright...then it's alright. Don't settle for the
later editions, look around for that one. It has been valued for decades
so there will be plenty of them around at ham flea markets and out on
the web. I have even seen that book cited in learned discourse.

So far as an "A" to "B" comparison goes, just take screen grabs of

Rune's display. "Screenshot" is in use here on a Linux system and then
use G.I.M.P. or similar to overlay one graph upon another.

John

at radio station VE7AOV

+++++


On 2019-09-20 10:33 a.m., Ken Buscho wrote:

Hi, Folks,
My whole NanoVNA process started because I went out on eBay looking for an antenna analyzer for ham VHF/UHF use and got my white model because it intrigued me at what was being done at that price point. No prior personal experience with VNAs, although I've been aware of them for years. Big learning curve to get started, but it did almost everything I was looking for once I could see SWR and a Smith Chart. It's been well worth the $60, and I'm getting a VNA education to boot reading here.

I say almost because I would like to be able to get some values to at least compare HT Antenna A to HT Antenna B for gain. To get started, I put a test antenna on CH0 and a reference antenna on CH1. I can tell the CH1 antenna is "seeing" the CH0 antenna because logmag dB values change with/without something on CH0, and I can also see that dB values go up/down as antenna distances change.

What I'm looking for is suggestions on how to do this the right way, or at least a better way. Now I'm using a scanner-type antenna for reference, it's about 30cm/12" away from the test antenna. I'm looking for suggestions on ref antenna type/spacing, and also a calibration protocol to make this choice useful. Nothing really fancy, I just want to get some data so when someone shows up with what they think is an antenna that's cooler that what they (or someone else) already has, I want to have some numbers to avoid a food fight and/or be able to objectively evaluat/comapre the two. Suggestions? Issues?

Appreciate the input...

Ken Buscho
KB6KOB

--

Replacement.
You paid for a working unit.
Not your job to sort out their crap.
And you have no course of redress if you break your unit.

73 de Andy

The switch is very easy to remove and replace with same or you can do what I and a few others did - replace with surface mount buttons on the front cover (search my posts)
Essentially, use a needle tip iron and desolder the two pads under the switch at the outside edge of the PCB while gently pulling up on the switch. Then desolder the 3 other switch pins. Go slow and apply just enough heat to melt the solder.
Look at my PDF in the files section of alternat input buttons.

Regards
Larry

Ugggghhh, don’t mention near-field to me. For me it is the stuff from nightmares. A few times I was called in to investigate communication problems on ships and mobile command centers, where the HF antennas were separated by a few meters. What a nightmare, on certain frequencies the coupling was less than 2dB’s between 2 1kW stations. Taking into account that the PA’s could deliver 1kW into a VSWR of 2:1, you dont want to see what hit the receiver on the other antenna if the system was tuned to the same frequency....

In combination with FW ch.dfu (edy555_0.1.1.9):
I discovered today that with NanoVNA Saver v0.0.10 you may NOT set the LCD of the Nano to TDR. Otherwise, the screens in Saver 10 are not correct.
Well, if you want to measure TDR, you can only do that on the Nano LCD itself. If the NanoVNA is NOT set to TDR (transform), the screens in Saver 10 are correct. Thanks anyway for the good software Rune.

Hi All

I just got my NanoVNA from an Ebay seller who charged above average promissing better quality and construction. End result is that the unit came with a jammed/sticky and clearly faulty switch. The seller wants to send me a replacement switch. I noticed that its an SMT mount switch with very fine trances connecting to the switch. When i opened the case the switch just about crumbled in my hand. It looks like the plastic is totally crap like it was printed on a 3d printer very brittle. I doubt that even if I replaced it that it would last a long time.

Anyone had luck or experience replacing this switch, or should I just ask for a refund or replacement?

Thanks

On Fri, 20 Sep 2019 at 18:33, Ken Buscho <kb6kob@...> wrote:

Hi, Folks,
My whole NanoVNA process started because I went out on eBay looking for an
antenna analyzer for ham VHF/UHF use and got my white model because it
intrigued me at what was being done at that price point. No prior personal
experience with VNAs, although I've been aware of them for years. Big
learning curve to get started, but it did almost everything I was looking
for once I could see SWR and a Smith Chart. It's been well worth the $60,
and I'm getting a VNA education to boot reading here.

I say almost because I would like to be able to get some values to at
least compare HT Antenna A to HT Antenna B for gain. To get started, I put
a test antenna on CH0 and a reference antenna on CH1. I can tell the CH1
antenna is "seeing" the CH0 antenna because logmag dB values change
with/without something on CH0, and I can also see that dB values go up/down
as antenna distances change.

What I'm looking for is suggestions on how to do this the right way, or at
least a better way. . Suggestions? Issues?

Appreciate the input...

Ken Buscho
KB6KOB

I don’t think you will manage just using the NanoVNA. First understand that
as hams we are interested in the far field performance. If you are working
between a few hundred kHz, the near field maybe important, but generally
you are only interested in the far field properties.

There are two ways to measure the far field gain of an antenna.

1) *Far field* measurements usually made on an antenna test range. Only the
amplitude of signals need to be measured. Amateurs can do this.

2) *Near field *measurements made in an anechoic chamber measuring both
amplitude and phase. The receiving probe needs to scan over the whole
antenna. Amplitude and phase need to be measured, so a VNA or similar is
essential. Once you have the near field pattern, the far field can be
computed by a Fourier Transform of the near field. This is totally out of
the question for hams to do - it needs very specialist equipment.

*So you need to make far-field measurements. *

In order to make far field measurements, the antennas need to be
sufficiently far apart - a distance R of

R = 2 D^2 / lambda

where D is width of the antenna.



Assuming isotopic radiators, the loss is called the free space path loss
(FSPL)



What I believe you will find is that the free space path loss will be too
high to measure with the NanoVNA. The dynamic range of the NanoVNA will not
be high enough. I suggest that you work out the distance to the far field,
then work out the attenuation in dB to check this. Adding a power amplifier
after calibration could help, but you will still probably be unable to do
it.

A more practical way will be the power output from an amateur transceiver
and a calibrated power meter, which could be a receiver. *Much* greater
attenuations can be measured this way.

I am 99.9% sure that the dynamic range of the NanoVNA will be insufficient.

Dave




--
Dr. David Kirkby,
Kirkby Microwave Ltd,
drkirkby@...

Telephone 01621-680100./ +44 1621 680100

Registered in England & Wales.
Company number 08914892.
Registered office:
Stokes Hall Lodge,
Burnham Rd,
Althorne,
Chelmsford,
Essex,
CM3 6DT,
United Kingdom

See firmware folder

/g/nanovna-users/files/Firmware/NanoVNA%20firmware%20build%20by%20Erik/Release%200.1.1%20with%20added%20scan%20command%20and%202.1GHz.zip

On Sat, 21 Sep 2019 at 10:07, Andy G0FTD via Groups.Io <punkbiscuit=
[email protected]> wrote:

On Sat, Sep 21, 2019 at 01:20 AM, <qrp.ddc@...> wrote:

Yes, limiter diode will ruin measurement. There are two issues with

diode:

- it add parasitic reactance
- it add non-linear distortions of the signal

100% agree.

There is no simple way to protect RF device with no deterioration of it's
dynamic range.

Seems to be that way.

I had a brief research period last yesterday just to look up how others
deal with this issue.

It seems they don't, and simply practice safe procedure.

Spectrum Analysers on the other hand have much higher input levels, and do
have some
solutions, but are cannot be used in the case of a network analyser.

It obviously depends on individual instruments, but a quick check of mine
shows that the HP 8720D 20 GHz VNA I have, is *much* more tolerant of high
power & DC than my 22 GHz spectrum analyzer.

*8720D 50 MHz-20 GHz VNA*
* 40 V DC
* +30 dBm max
* No electrostatic discharge

*HP 70905A RF section of spectrum analyzer, 50 kHz to 22 GHz.*
* 0 V DC
* 15 to 30 dBm depending on the value of an internal attenuator.

Given that the attenuator in the SA is set by the the user from the
interface, I would say assuming it’s set to 0 dB is sensible, so the
maximum power is 15 dBm. That makes the power handling of the VNA 32 times
higher than the SA, and the VNA tolerating 40 V DC compared to 0 V of the
SA.

I remember my favourite instrument, a Hewlett Packard HP8594 SA having a
blown front end and getting a quote for repair.

73 de Andy

--
Dr. David Kirkby,
Kirkby Microwave Ltd,
drkirkby@...

Telephone 01621-680100./ +44 1621 680100

Registered in England & Wales.
Company number 08914892.
Registered office:
Stokes Hall Lodge,
Burnham Rd,
Althorne,
Chelmsford,
Essex,
CM3 6DT,
United Kingdom

Hi Rune
V0.0.10 works fine, thank you.
May I suggest that the selection dots for the markers had a toggle function such that when these was not marked the were locked and when marked the marker was moveable. Alternative a further line called lock markers. My eager right hand fingers hit very often the left mouse key and the active marker is suddenly somewhere else.
Also if the vertical unit were scaleable would be nice e.g. to have selectable dB ranges in steps or freely selectable. Same applies for polar plot to e.g. to be able to study a load close in if inductive or capacitive or both.
Kind regards
Kurt

-----Oprindelig meddelelse-----
Fra: [email protected] <[email protected]> P? vegne af Rune Broberg
Sendt: 18. september 2019 22:36
Til: [email protected]
Emne: Re: [nanovna-users] NanoVNA Saver

I just released 0.0.10:


It's not the most exciting release, but it offers some quality of life improvements, such as the ability to choose the font size (particularly useful for Linux users, whose default is a massive 11 pt font).

It also adds debug logging: -d to get log messages to the terminal, or -D filename.txt to log to a file. Useful if you see crashes!

Additionally, it now supports importing magnitude/angle touchstone files, and there's been a number of little bugfixes.

As ever, I look forward to hearing what bugs you find, and what new features you want! :-)

--
Rune / 5Q5R

Hello,

We just uploaded the Agenda of 31st ANAMET Meeting:


and changed [.htaccess]:


Sincerely,

yin&pez@arg

1

Hi Erik
May I add the short should have a pin sitting directly onto a shorting disk which mates with the calibration plane
Kind regards
Kurt

-----Oprindelig meddelelse-----
Fra: [email protected] <[email protected]> P? vegne af erik@...
Sendt: 21. september 2019 08:30
Til: [email protected]
Emne: Re: [nanovna-users] What options should I look for?

The dummy guide to buying a nanoVNA:

This is the shop of the person that started all this and he delivers good product in excellent packaging.


But if you want to go cheaper these are your options:
Getting the calibration loads is good.
Look for those where the "open" has a hole where the "short" has a pin The cables are also nice as they allow you to have an identical test configuration as many people in this group.
Testing has shown the shielding does not realy make a difference.
Battery is very useful for testing antennas on places where you do not dare to bring a computer.
For the rest, one it arrives, test it and if you are not able to calibrate, request a refund.

On Sat, Sep 21, 2019 at 01:20 AM, <qrp.ddc@...> wrote:

Yes, limiter diode will ruin measurement. There are two issues with diode:
- it add parasitic reactance
- it add non-linear distortions of the signal

100% agree.

There is no simple way to protect RF device with no deterioration of it's
dynamic range.

Seems to be that way.

I had a brief research period last yesterday just to look up how others deal with this issue.

It seems they don't, and simply practice safe procedure.

Spectrum Analysers on the other hand have much higher input levels, and do have some
solutions, but are cannot be used in the case of a network analyser.

I remember my favourite instrument, a Hewlett Packard HP8594 SA having a blown front end and getting a quote for repair.

You could build a aircraft carrier at those prices, whence why the company was always known as High Price ;-)

In the end, I just used a buffer amplifier for general sniffing around as a precaution when it was suitable.

73 de Andy

Hi all,


There are several similar Nanovna clones on the market.
I would like to know what I have (or what perhaps not).

How do I read out my NanoVNA's firmware version?

Is there perhaps a list with info about the different versions?

Is there perhaps also a list with hardware versions?

Anything exhaustive?

Or is there no system perhaps, just chaos, as every producer does what
seems good to him without coordination with other manufacturers?

If so: Did someone try to collect all such info and make it available?


Hans, DJ7BA


---
Diese E-Mail wurde von Avast Antivirus-Software auf Viren geprüft.

Can you publish or send me your "experimental" firmware? I would like to run some tests on it.

Hi Nick,
thanks for the suggestions! Currently, I have no plans to separate the
plots from the main window, as I see them as a main feature of the
application, and want them there. The code doesn't have anything preventing
it, but I'm not personally going to work on a design that does that, as a
matter of prioritizing what time I have to work on it :-)

File pickers for load/save calibration really should have been in already,
I agree. I'll look at it :-)

And yes, you should definitely get a bigger monitor. ;-)

--
Rune / 5Q5R

The dummy guide to buying a nanoVNA:

This is the shop of the person that started all this and he delivers good product in excellent packaging.


But if you want to go cheaper these are your options:
Getting the calibration loads is good.
Look for those where the "open" has a hole where the "short" has a pin
The cables are also nice as they allow you to have an identical test configuration as many people in this group.
Testing has shown the shielding does not realy make a difference.
Battery is very useful for testing antennas on places where you do not dare to bring a computer.
For the rest, one it arrives, test it and if you are not able to calibrate, request a refund.

There are so many nanovna versions out there and the price varies quite a bit.To get the "best bang for the buck" what should I consider?
1- input shielding2- Calibration loads3- battery4- short m-m cables5- ?????
Thanks for any advice.